Rule: 

--
Sid: 
2925

-- 
Summary: 
This event is generated when an image fitting the profile of a web bug
has been detected in network traffic.

-- 

Impact: 
Information disclosure.

--
Detailed Information:
Web bugs are 1x1 pixel image files that are found in web pages or HTML
email. These are often used to monitor and track a users activity on the
web. Information such as the browsers IP address, cookie information,
time, browser version and other user identifiable charateristics can be
collected using web bugs.

This rule identifies an image that conforms to the usual size and format
of a web bug.

--
Affected Systems:
	All.

--
Attack Scenarios: 
An attacker can use this type of image in an HTML email or on a web
page to gather information about the host and user. Since these images
can be not only small but transparent, they are almost undetectable in
HTML pages.

-- 
Ease of Attack: 
Simple.

-- 
False Positives:
None known.

--
False Negatives:
None known.

-- 
Corrective Action: 
Disallow the use of HTML email

Use a web proxy server to strip all web bug images from server
responses.

--
Contributors: 
Sourcefire Vulnerability Research Team
Alex Kirk <alex.kirk@sourcefire.com>
Nigel Houghton <nigel.houghton@sourcefire.com>

-- 
Additional References:


--
