Adobe confirms PDF zero-day, urges users to kill JavaScript

Computerworld - Adobe Systems Inc. late yesterday acknowledged that all versions of its popular PDF software, including editions for Windows, the Mac and Linux, contain at least one, and possibly two, critical vulnerabilities.

"All currently supported shipping versions of Adobe Reader and Acrobat, [Versions] 9.1, 8.1.4 and 7.1.1 and earlier, are vulnerable to this issue," said David Lenoe, the company's security program manager, in a blog entry yesterday. Lenoe was referring to a bug in Adobe's implementation of JavaScript that went public early Tuesday.

"Adobe is also currently investigating the issue posted on SecurityFocus as BID 34740," Lenoe added. That "Bugtraq ID," or BID number has been assigned to a second JavaScript vulnerability in Adobe's Reader.

Proof-of-concept attack code for both bugs has already been published on the Web.

According to Lenoe, Adobe will patch Reader and Acrobat, though he did not spell out a timetable for the fixes. "We are working on a development schedule for these updates and will post a timeline as soon as possible," he said.

In lieu of a patch, Lenoe recommended that users disable JavaScript in Reader and Acrobat by selecting Preferences from the Edit menu, choosing "JavaScript," then unchecking the "Enable Acrobat JavaScript" option. (On the Mac, Preferences is under the "Adobe Reader" or "Adobe Acrobat" menus.) That recommendation is identical to what he offered two months ago when Adobe owned up to a different critical vulnerability, one that was already being used by attackers at the time.

This week, however, Adobe reacted faster to reports that its software was vulnerable. In February, Adobe acknowledged the bug on Feb. 19, but waited until Feb. 24 to recommend disabling JavaScript.

If Adobe's patching pace for the newest bugs matches that of the February incident, it should have a fix available during the week of May 18.

Andrew Storms, director of security operations at nCircle Network Security Inc., who yesterday blasted Adobe for its long-running "rash" of JavaScript vulnerabilities, today applauded the company for reacting faster -- even as he again criticized its buggy software.

"Getting mitigations and work-around information out in front of the people in the security trenches is key," Storms said in an instant message. "Unfortunately, for Adobe, disabling JavaScript is a broken record, [and] similar to what we've seen in the past with Microsoft on ActiveX bugs."

Some security experts have urged users to switch PDF viewers. Finnish security company F-Secure Corp. repeated that recommendation today. "We've said it before, but it's worth repeating -- use an alternative to Adobe Acrobat Reader," said Patrik Runald, a security response manager at F-Secure, in a notice on the company's site. "[And] if you can't change from Adobe Reader, we strongly recommend that you disable its ability to run JavaScript."

More information will be posted to Adobe's security site as it becomes available, said Lenoe.