Many corporations spent last weekend playing “Whack-a-Worm”, attempting to eradicate the “Here You Have” worm. The major problem with viruses and worms is that once you think you have removed them from your network, another outbreak pops up. Nessus plugin 49211, “Here You Have Email Worm Detection”, has been added to the plugin feed and is available for both ProfessionalFeed and HomeFeed users. This plugin examines a Microsoft Windows system to detect the presence of the “Here You Have” worm. Note that you will need credentials on the target system for this plugin to work.
Security professionals first observed the worm on Thursday or Friday. Over the weekend, the worm spread considerably, infecting organizations such as the Florida Department of Transportation, ABC, Comcast, AIG, Disney and Proctor & Gamble. The worm primarily spreads via e-mail and requires a user to click a link in the e-mail. This action loads a web page that prompts the user to open a file that appears to be a PDF, WMV or other presumably “safe” file type. In reality, the file is a .scr file (screensaver) and once executed, will infect the system. While known as the “Here You Have” worm, based on the subject of the e-mail that propagates the worm, it may also use “Just for you” and “Hi” as the subject. Microsoft labeled the worm “Worm:Win32/Visal.B” and carries other designations, depending on the antivirus vendor.
Written in Visual Basic, the worm will infect the host and promptly disable any antivirus software on the system. It will then use contacts from Microsoft Outlook and Yahoo! Messenger to send copies of itself to as many users as possible. Locally, it will attempt to spread via removable media (e.g., USB drives) and network shares.
Nessus plugin 49211 detects the worm’s presence by examining several files on the system for indication that they were placed there by the worm. If detected, Tenable recommends you follow Microsoft’s directions for the safe removal of the malicious software. While Nessus does not focus on anti-malware, it can help provide a layered approach to dealing with virus and worm outbreaks by verifying that remediation measures have been comprehensive. No one wants to spend another weekend playing “Whack-a-Worm.”
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