US-CERT Technical Cyber Security Alert TA09-088A -- Conficker Worm Targets Microsoft Windows Systems

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National Cyber Alert System

Technical Cyber Security Alert TA09-088A

Conficker Worm Targets Microsoft Windows Systems

Original release date: March 29, 2009
Last revised: --
Source: US-CERT

Systems Affected

* Microsoft Windows

Overview

US-CERT is aware of public reports indicating a widespread
infection of the Conficker worm, which can infect a Microsoft
Windows system from a thumb drive, a network share, or directly
across a network if the host is not patched with MS08-067.

I. Description

The presence of a Conficker infection may be detected if a user is
unable to surf to the following websites:

* http://www.symantec.com/norton/theme.jsp?themeid=conficker_worm&inid=us_ghp_link_conficker_worm
* http://www.mcafee.com

If a user is unable to reach either of these websites, a Conficker
infection may be indicated (the most current variant of Conficker
interferes with queries for these sites, preventing a user from
visiting them). If a Conficker infection is suspected, the
infected system should be removed from the network. Major
anti-virus vendors and Microsoft have released several free tools
that can verify the presence of a Conficker infection and remove
the worm. Instructions for manually removing a Conficker infection
from a system have been published by Microsoft in
http://support.microsoft.com/kb/962007.

II. Impact

A remote, unauthenticated attacker could execute arbitrary code on
a vulnerable system.

III. Solution

US-CERT encourages users to prevent a Conficker infection by
ensuring all systems have the MS08-067 patch (part of Security
Update KB958644, which was published by Miscrosoft in October
2008), disabling AutoRun functionality (see
http://www.us-cert.gov/cas/techalerts/TA09-020A.html), and
maintaining up-to-date anti-virus software.

IV. References

* Virus alert about the Win32/Conficker.B worm -
<http://support.microsoft.com/kb/962007>

* Microsoft Security Bulletin MS08-067 - Critical -
<http://www.microsoft.com/technet/security/Bulletin/MS08-067.mspx>

* Microsoft Windows Does Not Disable AutoRun Properly -
<http://www.us-cert.gov/cas/techalerts/TA09-020A.html>

* MS08-067: Vulnerability in Server service could allow remote code
execution -
<http://support.microsoft.com/kb/958644>

* The Conficker Worm -
<http://www.symantec.com/norton/theme.jsp?themeid=conficker_worm>

* W32/Conficker.worm -
<http://us.mcafee.com/root/campaign.asp?cid=54857>

____________________________________________________________________

The most recent version of this document can be found at:

<http://www.us-cert.gov/cas/techalerts/TA09-088A.html>
____________________________________________________________________

Feedback can be directed to US-CERT Technical Staff. Please send
email to <cert@cert.org> with "TA09-088A Feedback VU#827267" in
the subject.
____________________________________________________________________

For instructions on subscribing to or unsubscribing from this
mailing list, visit <http://www.us-cert.gov/cas/signup.html>.
____________________________________________________________________

Produced 2009 by US-CERT, a government organization.

Terms of use:

<http://www.us-cert.gov/legal.html>
____________________________________________________________________

Revision History

March 29, 2009: Initial release

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