A day after Adobe patched a serious security hole in its Reader and Acrobat programs, miscreants are flooding email inboxes with malware-tainted PDF files that try to remotely hijack vulnerable computers.

The malware, identified by Symantec researchers as Trojan.Pidief.A, is included in PDF files attached to a "fair number of emails," according to this blog entry (http://www.symantec.com/enterprise/security_response/weblog/2007/10/when_pdfs_attack_again.html). The spam typically targets specific businesses or organizations.

Adobe issued a patch for the vulnerability on Monday. The revelation of in-the-wild exploits underscores the importance of updating immediately. A patch for Reader is available here (http://www.adobe.com/support/downloads/detail.jsp?ftpID=3806); an Acrobat update is available here (http://www.adobe.com/support/downloads/product.jsp?product=1&platform=Windows).

Emails typically arrive bearing subjects such as "invoice," "statement" or "bill" and contain no text in the body. If the attached PDF is opened using a vulnerable version of Adobe software, the machine will execute code that lowers Windows security settings and installs a bevy of nasty malware, according to the SANS Internet Storm Center.

At least some of the spam comes courtesy of the Russian Business Network, a St. Petersburg-based service provider that offers bullet-proof hosting to criminals engaged in child pornography, identity theft and spam, according to Ken Dunham, director of global response at iSIGHT Partners. "The code and servers used in the attack are nearly identical to September 2006 Vector Markup Language (VML) zero-day attacks that took place one year ago," he wrote in an email.

For more information about the Russian Business Network and how it operates, check out this article (http://www.washingtonpost.com/wp-dyn/content/article/2007/10/12/AR2007101202461.html) published by The Washington Post. ®

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