Today we saw another malicious PDF attempting to exploit the new zero-day vulnerability in Adobe Reader and Acrobat [CVE-2009-0658, APSA09-01]. The Sophos advisory for this vulnerability can be found here. This latest sample is also proactively detected, as Mal/JSShell-B.
I quickly fired up a goat machine, intentionally disabling this detection in the Sophos product to see how the buffer overflow protection (BOPs) would fare. Success! BOPs triggered shortly after loading the malicious PDF in Adobe Reader 9.0.0 (freshly downloaded and installed).
Whilst we wait for a patch from Adobe, to help protect yourselves from attacks:
- Ensure you keep your products correctly updated
- Enable runtime protection (HIPs and BOPs) - not just in alert-only mode
- Consider some of the mitigation steps outlined in my previous post.