Following last week's announcement of a zero-day vulnerability for PowerPoint (CVE-2014-4114), we suspected it would not be too long before we saw this attack being used via email attachments. So when this email with a PowerPoint attachment appeared in our spam traps, it kinda stuck out, as we don't typically see a lot of PowerPoint attachments.
A quick look at the unpack tree from our Secure Email Gateway showed the presence of a couple of OLEObject bin files. Hmm, definitely worth a look.
A quick look at these bin files in an editor confirmed the presence of code attempting to download two files from an external source. The files in this case 37.59.5.18\11\test.gif and 37.59.5.18\11\test.inf
Unfortunately, by the time we looked, these files were no longer available on the remote server and we could not analyze them further. However, the VirusTotal result for the PowerPoint file can be seen here. In the comments, you can see another party has identified test.gif as an executable with its VirusTotal result suggesting some kind of downloader. The point here is that any executable file can be downloaded and automatically executed if this PowerPoint file was opened on a vulnerable system.
Analysis of the email suggests it originated from a variant of the Cutwail spambot, as the message shared characteristics with other Cutwail malicious spam campaigns we have seen recently, including those with zipped executables, and Word macro malware. Our Trustwave Secure Email Gateway (SEG) blocked these messages based on Cutwail-related rules. The messages were also sent to honeypot addresses meaning this was not a targeted attack like other reported cases to date. It's more of a broad brush experiment by the spam botmasters with a new tool--CVE-2014-4114.
Given the relative simplicity and effectiveness of this attack, we would expect a lot more email-borne PowerPoint files of this nature in the near future. If you haven't patched your systems yet, we recommend you do so immediately.
Customers of Trustwave Secure Web Gateway were also protected against this vulnerability out-of-box by the policy rule "Block MS Office Documents Containing Macros/Embedded Files". Additional protection targeting this particular vulnerability was also released as part of "Security Update 173."
