Adobe Systems has pushed out an emergency update that patches at least 17 holes in its Reader and Acrobat applications, including two serious bugs that are being used by online criminals to install malware on end-users' machines.
The fixes address a vulnerability in Windows, Mac, and Linux versions of the reader that allows hackers to remotely install malware on end-users' machines by tricking them into opening a booby-trapped document. The same flaw was patched 18 days ago in Adobe's Flash Player, also in an unscheduled release because of in-the-wild attacks. The flaw resided in the authplay.dll, AuthPlayLib.bundle, or libauthplay.so.0.0.0 files on Windows, Mac, and Linux machines respectively.
The update also fixes a vulnerability first demonstrated by researcher Didier Stevens. By misusing a feature contained in the PDF specification, his proof-of-concept attack showed how hackers could embed a malicious payload in a document and trick Adobe's Reader and Acrobat applications — as well as the competing FoxIT Reader — into executing it. Adobe said it has added code to block any attempts to launch an executable file by default. Engineers have also altered the way the existing warning dialog works to thwart known social-engineering attacks.
Adobe wasn't scheduled to release patches until July 13, but because the critical vulnerabilities were actively being exploited, the company decided to push out the fixes ahead of time. The update fixes at least 15 other security bugs. The next security update for Reader and Acrobat is scheduled for October 12.
In a blog post accompanying the update, Adobe said a new mechanism that automatically updates Reader and Acrobat, which was unveiled for Windows and Mac users in April, is already seeing results. Adobe's April 13 update was adopted about three times faster than previous updates, the company said.