List, I've completed the second paper in my series analyzing Sophos
Antivirus internals, titled "Practical Attacks against Sophos
Antivirus". As the name suggests, this paper describes realistic
attacks against networks using Sophos products.
The paper includes a working pre-authentication remote root exploit
that requires zero-interation, and could be wormed within the next few
days. I would suggest administrators deploying Sophos products study
my results urgently, and implement the recommendations.
I've also included a section on best practices for Sophos users,
intended to help administrators of high-value networks minimise the
potential damage to their assets caused by Sophos.
The paper is available to download at the link below.
https://lock.cmpxchg8b.com/sophailv2.pdf
A working exploit for Sophos 8.0.6 on Mac is available, however the
techniques used in the exploit easily transfer to Windows and Linux,
due to multiple critical implementation flaws described in the paper.
Testcases for the other flaws described in the paper are available on
request.
https://lock.cmpxchg8b.com/sophail-rev3-exploit.tar.gz
It is my understanding that Sophos plan to publish their own advice to
their customers today. I have not been given an opportunity to review
the advice in advance, so cannot comment on it's accuracy.
I have had a working exploit since September, but Sophos requested I
give them two months to prepare for this publication before discussing
it. A timeline of our interactions is included in the paper. I believe
CERT are also preparing an advisory. I'm currently working on the
third paper in the series, which I'll announce at a later date. Please
contact me if you would like to be a reviewer. I will add any last
minute updates to twitter, at http://twitter.com/taviso.
If you would like to learn more about Sophos internals, you can read
my previous paper in the series here
https://lock.cmpxchg8b.com/sophail.pdf
I've reproduced a section of the conclusion below.
Tavis.
Conclusion