Reports are emerging that Adobe's PDF Reader contains a critical vulnerability, and the company has confirmed it is investigating.
The bug was first disclosed Monday on the SecurityFocus site, which posted a link to proof-of-concept attack code. "An attacker can exploit this issue to execute arbitrary code with the privileges of the user running the application," said the advisory.
According to SecurityFocus, the most up-to-date versions, Reader 9.1 and Reader 8.1.4, are vulnerable. The Linux versions definitely have the bug, and other platforms - Adobe also provides Reader for Windows and the Mac - may be at risk as well.
For its part, Adobe's acknowledgement was brief. "Adobe is aware of reports of a potential vulnerability in Adobe Reader 9.1 and 8.1.4," said David Lenoe, the company's security program manager, in a security blog entry. "We are currently investigating, and will have an update once we get more information."
An Adobe spokesman declined to answer questions about the bug, saying that all the company had to offer at the moment was Lenoe's comments. More information, he promised, would be published to the blog, or to Adobe's security advisory page.
The short confirmation was reminiscent of Adobe's admission two months ago when it said Reader contained one or more bugs. In that incident, attackers had been exploiting the vulnerability for as many as six weeks, possibly more.
Adobe patched that flaw, and several others, starting on 10 March, fixing first Reader 9, then working its way down to Reader 8 and even older versions at one-week intervals.
"It's time that Adobe stepped up to the challenge," he said, adding that Adobe was a good example of a company that should try to emulate Microsoft's approach to security. "This is another proof-of-concept that's been made public," Storms said. "It's in stark contrast to Microsoft, which somehow manages to get most people to report vulnerabilities responsibly."
While some security experts have recommended users switch to alternate PDF viewers - Mikko Hypponen, F-Secure's chief research officer, is perhaps the most prominent - Storms was unwilling to name a replacement. "There's always an up side and a down side," he said. "The Adobe line is really intended for the enterprise, and you may not get that in other products. But with the long rash of vulnerabilities with Adobe products, you have to ask yourself, 'Is it worth it to support Adobe?'"
Symantec, which had discovered in-the-wild exploits targeting that earlier vulnerability more than a week before Adobe owned up to the bug, was not able to immediately respond to questions about whether its honeypot network had found any rigged PDFs leveraging this new flaw.