XSS, Reflected Cross Site Scripting, CWE-79, CAPEC-86, DORK, GHDB, nist.gov

The value of the Referer HTTP header is copied into an HTML comment. The payload 37ba9--><script>alert(1)</script>c42eb69629a 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 HTML comment tags does not prevent XSS attacks if the user is able to close the comment or use other techniques to introduce scripts within the comment context.

Issue background

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.

Request

GET /cgi-bin/exit_nist.cgi HTTP/1.1
Host: www.nist.gov
Accept: */*
Accept-Language: en
User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0)
Connection: close
Cookie: fsr.s={"v":1,"rid":"1304125248634_871119"}; CFTOKEN=89200427; fsr.a=1304125245932; CFID=17042989;
Referer: http://www.google.com/search?hl=en&q=37ba9--><script>alert(1)</script>c42eb69629a

Response

HTTP/1.1 200 OK
Date: Sat, 30 Apr 2011 12:39:42 GMT
Server: Apache
NIST: g3
Connection: close
Content-Type: text/html; charset=ISO-8859-1
Content-Length: 535

<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" lang="en-US" xml:lang="en-US">
<
...[SNIP]...
<script>alert(1)</script>c42eb69629a-->
...[SNIP]...

2. Cookie without HttpOnly flag set previous next

Summary

Severity:	Low
Confidence:	Firm
Host:	http://www.nist.gov
Path:	/search-results.cfm

Issue detail

The following cookies were issued by the application and do not have the HttpOnly flag set:

CFID=17042990;path=/
CFTOKEN=54636047;path=/

The 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.

Issue background

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.

Request

GET /search-results.cfm?q=xss.cx&btng=Search&num=10&sortType=L&scopeType=0&datefrom=&dateto= HTTP/1.1
Host: www.nist.gov
Proxy-Connection: keep-alive
Referer: http://www.nist.gov/srd/onlinelist.htm
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.205 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

Response

HTTP/1.1 200 OK
Date: Sat, 30 Apr 2011 01:00:13 GMT
Server: Apache
Set-Cookie: CFID=17042990;path=/
Set-Cookie: CFTOKEN=54636047;path=/
Last-Modified: Tue, 4 Jan 2011 22:32:06 GMT
NIST: g3
Content-Type: text/html; charset=iso-8859-1
Content-Length: 18308

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> <!-- Conte
...[SNIP]...

3. Cross-domain POST previous next
There are 2 instances of this issue:

/search-results.cfm
/srd/onlinelist.htm

Issue background

The POSTing of data between domains does not necessarily constitute a security vulnerability. You should review the contents of the information that is being transmitted between domains, and determine whether the originating application should be trusting the receiving domain with this information.

3.1. http://www.nist.gov/search-results.cfm next

Summary

Severity:	Information
Confidence:	Certain
Host:	http://www.nist.gov
Path:	/search-results.cfm

Issue detail

The page contains a form which POSTs data to the domain service.govdelivery.com. The form contains the following fields:

origin
login
code
signupbutton

Request

Response

3.2. http://www.nist.gov/srd/onlinelist.htm previous next

Summary

Severity:	Information
Confidence:	Certain
Host:	http://www.nist.gov
Path:	/srd/onlinelist.htm

Issue detail

The page contains a form which POSTs data to the domain service.govdelivery.com. The form contains the following fields:

origin
login
code
signupbutton

Request

GET /srd/onlinelist.htm HTTP/1.1
Host: www.nist.gov
Proxy-Connection: keep-alive
Referer: http://data.osbm.state.nc.us/pls/pbis/dyn_osbmweb_libdatalinks.show?p_arg_names=context&p_arg_values=facts
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.205 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

Response

HTTP/1.1 200 OK
Date: Sat, 30 Apr 2011 01:00:05 GMT
Server: Apache
NIST: g3
Content-Type: text/html; charset=UTF-8
Content-Length: 13113

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<!-- Con
...[SNIP]...
<div class="social20Wrapper">
<form method="post" action="https://service.govdelivery.com/service/multi_subscribe.html">
<input value="http://www.nist.gov/" name="origin" type="hidden" />
...[SNIP]...

4. Cross-domain Referer leakage previous next

Summary

Severity:	Information
Confidence:	Certain
Host:	http://www.nist.gov
Path:	/search-results.cfm

Issue detail

The page was loaded from a URL containing a query string:

http://www.nist.gov/search-results.cfm?q=xss.cx&btng=Search&num=10&sortType=L&scopeType=0&datefrom=&dateto=

The response contains the following links to other domains:

http://www.expectmore.gov/
http://www.time.gov/

Issue background

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

Response

5. Cross-domain script include previous next

Summary

Severity:	Information
Confidence:	Certain
Host:	http://www.nist.gov
Path:	/srd/onlinelist.htm

Issue detail

The response dynamically includes the following script from another domain:

http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js

Issue background

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.

Request

Response

HTTP/1.1 200 OK
Date: Sat, 30 Apr 2011 01:00:05 GMT
Server: Apache
NIST: g3
Content-Type: text/html; charset=UTF-8
Content-Length: 13113

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<!-- Con
...[SNIP]...
</title>
<script language="JavaScript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js" type="text/javascript"></script>
...[SNIP]...

6. Email addresses disclosed previous next
There are 2 instances of this issue:

/search-results.cfm
/srd/onlinelist.htm

Issue background

The presence of email addresses within application responses does not necessarily constitute a security vulnerability. Email addresses may appear intentionally within contact information, and many applications (such as web mail) include arbitrary third-party email addresses within their core content.

However, email addresses of developers and other individuals (whether appearing on-screen or hidden within page source) may disclose information that is useful to an attacker; for example, they may represent usernames that can be used at the application's login, and they may be used in social engineering attacks against the organisation's personnel. Unnecessary or excessive disclosure of email addresses may also lead to an increase in the volume of spam email received.

Issue remediation

You should review the email addresses being disclosed by the application, and consider removing any that are unnecessary, or replacing personal addresses with anonymous mailbox addresses (such as helpdesk@example.com).

6.1. http://www.nist.gov/search-results.cfm previous next

Summary

Severity:	Information
Confidence:	Certain
Host:	http://www.nist.gov
Path:	/search-results.cfm

Issue detail

The following email address was disclosed in the response:

DO-webmaster@nist.gov

Request

Response

6.2. http://www.nist.gov/srd/onlinelist.htm previous next

Summary

Severity:	Information
Confidence:	Certain
Host:	http://www.nist.gov
Path:	/srd/onlinelist.htm

Issue detail

The following email addresses were disclosed in the response:

DO-webmaster@nist.gov
inquiries@nist.gov

Request

Response

HTTP/1.1 200 OK
Date: Sat, 30 Apr 2011 01:00:05 GMT
Server: Apache
NIST: g3
Content-Type: text/html; charset=UTF-8
Content-Length: 13113

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<!-- Con
...[SNIP]...
<a href="mailto:inquiries@nist.gov">
...[SNIP]...
<a href="mailto:DO-webmaster@nist.gov">DO-webmaster@nist.gov</a>
...[SNIP]...
<a href="mailto:inquiries@nist.gov">inquiries@nist.gov</a>
...[SNIP]...

7. Content type incorrectly stated previous
There are 2 instances of this issue:

/favicon.ico
/style/web_fonts/functionpro_medium_macroman/FunctionPro-Medium-webfont.woff

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.

7.1. http://www.nist.gov/favicon.ico previous next

Summary

Severity:	Information
Confidence:	Firm
Host:	http://www.nist.gov
Path:	/favicon.ico

Issue detail

The response contains the following Content-type statement:

Content-Type: text/plain

The response states that it contains plain text. However, it actually appears to contain unrecognised content.

Request

GET /favicon.ico HTTP/1.1
Host: www.nist.gov
Proxy-Connection: keep-alive
Accept: */*
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.205 Safari/534.16
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

Response

HTTP/1.1 200 OK
Date: Sat, 30 Apr 2011 01:00:13 GMT
Server: Apache
Last-Modified: Thu, 30 Sep 2010 13:17:01 GMT
ETag: "3568017-13e-49179e4b54d40"
Accept-Ranges: bytes
Content-Length: 318
NIST: g3
Content-Type: text/plain

..............(.......(....... .........................................................................................................................................................................
...[SNIP]...

7.2. http://www.nist.gov/style/web_fonts/functionpro_medium_macroman/FunctionPro-Medium-webfont.woff previous

Summary

Severity:	Information
Confidence:	Firm
Host:	http://www.nist.gov
Path:	/style/web_fonts/functionpro_medium_macroman/FunctionPro-Medium-webfont.woff

Issue detail

The response contains the following Content-type statement:

Content-Type: text/plain

The response states that it contains plain text. However, it actually appears to contain unrecognised content.

Request

GET /style/web_fonts/functionpro_medium_macroman/FunctionPro-Medium-webfont.woff HTTP/1.1
Host: www.nist.gov
Proxy-Connection: keep-alive
Referer: http://www.nist.gov/srd/onlinelist.htm
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.16 (KHTML, like Gecko) Chrome/10.0.648.205 Safari/534.16
Accept: */*
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

Response

HTTP/1.1 200 OK
Date: Sat, 30 Apr 2011 01:00:08 GMT
Server: Apache
Last-Modified: Mon, 09 Aug 2010 19:57:20 GMT
ETag: "cfc91e-7e34-48d696c9aa800"
Accept-Ranges: bytes
Content-Length: 32308
NIST: g3
Content-Type: text/plain

wOFF......~4.......0........................FFTM..~.........SF.GGDEF..]....(...,.0..GPOS.._\......Q...s.GSUB..].........Z(L.OS/2.......[...`.V..cmap...l...z......A.cvt .......8...8....fpgm...........e
...[SNIP]...

Report generated by XSS.CX at Sat Apr 30 17:23:15 CDT 2011.

XSS, Reflected Cross Site Scripting, CWE-79, CAPEC-86, DORK, GHDB, nist.gov

Hoyt LLC Research investigates and reports on security vulnerabilities embedded in Web Applications and Products used in wide-scale deployment.

Contents

Public Domain Vulnerability Information, Security Articles, Vulnerability Reports, GHDB, DORK Search

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