GEN:SID 1:2056
Message WEB-MISC TRACE attempt
Summary This event is generated when an attempt is made to exploit a known
vulnerability in a web server using the TRACE command.
Impact Possible disclosure of information.
Detailed Information The TRACE method is used when debugging a webserver to ensure that
server returns information to the client correctly. When used with other
vulnerabilities it is possible to use the TRACE method to return
sensitive information from a webserver such as authentication data and
cookies.

This is known as a Cross Site Tracing (XST) attack.
Affected Systems All platforms running a webserver that responds to the TRACE method.
Attack Scenarios The attacker needs to perform a TRACE request to a vulnerable server.
Ease of Attack Simple
Corrective Action Disable the webserver from responding to TRACE requests.
Additional References CERT:
http://www.kb.cert.org/vuls/id/867593

Nessus:
http://cgi.nessus.org/plugins/dump.php3?id=11213

RFC:
http://www.ietf.org/rfc/rfc2616.txt
Rule References bugtraq: 9561
nessus: 11213
url: www.whitehatsec.com/press_releases/WH-PR-20030120.pdf