10 - TA09-088A

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

I. Description

Home users can apply a simple test for the presence of a Conficker/Downadup infection on their home computers. The presence of a Conficker/Downadup infection may be detected if a user is unable to surf to their security solution website or if they are unable to connect to the websites, by downloading detection/removal tools available free from those sites:

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

* http ://www.microsoft.com/protect/computer/viruses/worms/conficker.mspx

* http ://www.mcafee.com

If a user is unable to reach any of these websites, it may indicate a Conficker/Downadup infection. The most recent variant of Conficker/Downadup interferes with queries for these sites, preventing a user from visiting them. If a Conficker/Downadup infection is suspected, the system or computer should be removed from the network or unplugged from the Internet - in the case for home users.

II. Impact

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

III. Solution

Instructions, support and more information on how to manually remove a Conficker/Downadup infection from a system have been published by major security vendors. Please see below for a few of those sites. Each of these vendors offers free tools that can verify the presence of a Conficker/Downadup infection and remove the worm:

Symantec:
http://www.symantec.com/business/security_response/writeup.jsp?docid=2009-011316-0247-99

Microsoft:
http://support.microsoft.com/kb/962007

http://www.microsoft.com/protect/computer/viruses/worms/conficker.mspx

Microsoft PC Safety hotline at 1-866-PCSAFETY, for assistance.

US-CERT encourages users to prevent a Conficker/Downadup infection by ensuring all systems have the MS08-067 patch (see http://www.microsoft.com/technet/security/Bulletin/MS08-067.mspx), disabling AutoRun functionality (see http://www.us-cert.gov/cas/techalerts/TA09-020A.html), and maintaining up-to-date anti-virus software.