New Adobe Reader, Acrobat Vulnerability Comes Under Attack

A new zero-day bug affecting Adobe Reader and Acrobat is being exploited in the wild. Though the vulnerability affects the products on Unix, Mac and Windows systems, the exploit observed in the wild is focused on Microsoft Windows for the moment.

Adobe is warning users about a critical vulnerability in versions of Adobe Reader and Acrobat that is being exploited in targeted attacks.

While little information has been made available about the exact nature of the vulnerability, it has been described by VUPEN Security as a memory corruption error. According to the advisory from VUPEN, the bug can be exploited remotely to compromise a vulnerable system.

Though the bug is known to affect Adobe Reader and Acrobat versions 9.1.3 and earlier on Windows, Mac and Unix systems, the exploit found in the wild is only targeting Windows.

"Adobe plans to resolve this issue as part of the upcoming Adobe Reader and Acrobat quarterly security update, scheduled for release on October 13," blogged David Lenoe of the Adobe Product Security Incident Response Team. "Adobe Reader and Acrobat 9.1.3 customers with DEP (Data Execution Prevention) enabled on Windows Vista will be protected from this exploit."

Adobe's products have become a favorite target of attackers, most likely due to the prevalence of the company's PDF reader and Adobe Flash Player. In response Adobe opted to change its patching process, aligning the release of security updates with Microsoft's Patch Tuesday. The company also began reviewing legacy code as part of its development process when it updated its software.

As a workaround for this specific exploit, users can disable JavaScript. However, Adobe pointed out that a variant could be created that does not rely on JavaScript, so users should keep their antivirus definitions up-to-date.

Johannes Ullrich, a researcher with the SANS Institute, said users can also clean PDF documents by converting them into another format, such as Postscript, and then back into PDF.

"However, this is not 100 percent certain to remove the exploit and you may infect the machine that does the conversion as it will likely still use the vulnerable libraries to convert the document," he blogged. "But the likelihood of this happening is quite low."