Adobe released an unscheduled update to Reader and Acrobat on Tuesday that addresses a variety of security bugs in its PDF software, including an unpatched flaw that has become the subject of hacking attacks over recent weeks.
Updates of Adobe Reader and Acrobat 9.4 for Windows, Macintosh and Unix address a critical flaw in the way the PDF software renders Flash files, as explained in an advisory here.
The security vulnerability has been used in attacks against Adobe Reader users, so it's just as well Adobe has launched the update now rather than waited until its next scheduled quarterly patch batch, which isn't due until February. The software manufacturer released a fix for the same bug in stand-alone versions of Flash Player late last month, in time for its autumn patch batch.
Earlier version 8 installations of Reader and Acrobat are not vulnerable to the bug and therefore don't need patching. The latest version of Adobe Acrobat, version X, released earlier this week, is likewise immune. Version X contains much-vaunted Protected Mode (sandboxing) technology that aims to make Adobe's software more resistant to abuse by malware pedlars and miscreants. Early thoughts on whether or not this is likely to be effective can be found in a blog post by Paul Ducklin of net security firm Sophos here.
Adobe Reader X is not out until around the end of the month.
This staggered release schedule has created more than a little confusion, which has been exploited by hackers with offers of fake updates that actually offer malware. In response, Adobe advises users to ignore scams emails and to only download software from its website.
Updates to Adobe software are important because its software (particularly its PDF software) has been a number two target for hackers for some years. It only lags behind attacks on Microsoft applications and operating systems.
Adobe is applying a lot of effort to remedy this situation, but its efforts thus far have largely failed to impress. Part of its problem stems from the extravagantly open nature of the PDF specification, which supports all manner of scripting and embedded functionality that isn't needed in day-to-day use of the technologies, while offering opportunities for all manner of security exploits. Alternative PDF viewing applications, such as FoxIT, have also had problems on this score. ®