- This vulnerability affects: Adobe Reader and Acrobat 9.3.4 and earlier, on Windows, Mac, and UNIX computers
- How an attacker exploits it: Typically, by enticing your users into viewing a maliciously crafted PDF document
- Impact: An attacker can execute code on your computer, potentially gaining control of it
- What to do: Install Adobe’s Reader and Acrobat 9.4 updates as soon as possible (or let Adobe’s Updater do it for you).
About two weeks ago, we released an alert warning you of an Adobe Flash update that fixed a zero day vulnerability that attackers were exploiting in the wild. In that alert, we also mentioned that Adobe Reader was susceptible to the zero day flaw as well, but Adobe had not had time to patch it, and were planning to release a Reader update during the week of October 4th. As promised, yesterday Adobe released an update for Reader and Acrobat that fixes that flaw, and many others. Specifically, the update fixes 23 security vulnerabilities (number based on CVE-IDs) in Adobe’s popular PDF reader.
The 23 flaws differ technically, but many of them consist of memory corruption vulnerabilities that share the same general scope and impact. If an attacker can entice one of your users into downloading and opening a maliciously crafted PDF document (.pdf), many of these vulnerabilities can be exploited to execute code on that user’s computer, with that user’s privileges. If your user has local administrative privileges, the attacker gains full control of the user’s machine.
This update fixes many serious flaws, including one that attackers have exploited in the wild. We greatly encourage you to download and install this Reader update as soon as possible. Also note, Adobe typically sticks to a quarterly patch cycle that falls on the same day as Microsoft Patch Day (the second Tuesday of the month). However, since they chose to release this Reader update early due to its critical nature, they will not release any Reader updates on their normally scheduled patch day, October 12. Their next Reader update is due February 8th, 2011.
Adobe has released Reader and Acrobat 9.4 updates to fix these vulnerabilities on all platforms. You should download and deploy the corresponding updates immediately, or let the Adobe Software Updater program do it for you.
- Adobe Reader 9.4
- Adobe Acrobat
Does My Firewall Help?
Many firewalls can block incoming PDF files. However, most administrators prefer to allow these file types for business purposes. Nonetheless, if PDF files are not absolutely necessary to your business, you may consider blocking them using the firewall’s HTTP and SMTP proxy until the patch has been installed.
Adobe has released patches that correct these vulnerabilities.
This alert was researched and written by Corey Nachreiner, CISSP.