July 2010 Threat Report: Zero-days attacked in the wild, Obfuscated emails circulate

Our July 2010 Threat Report has been posted, below are some findings from the activity recap:

Global detected malware volume continued its rise from last report, reaching levels observed earlier in the year. One major contributor to this was the Sasfis botnet, as it continued its strong run. Eight Sasfis variants landed in our Top 10 Malware listing this report. This is a recurring theme, as developers and their very own creations continue to roll out updated copies of themselves. Earlier in the year, the Sasfis botnet was dedicated to downloading and executing software (primarily FakeAV) on infected systems. This period, we observed Sasfis to heavily spam as it downloaded updated spamming modules. Typical examples of spam from Sasfis include fake UPS invoices and Facebook photo links.

Spam bots such as Cutwail continue to diversify, sending a variety of spam themes on a frequent basis. One spam email we observed from Pushdo was a phish for Amazon.com. This is a classic phish, easily detected by hovering over the link and observing where you are really going. Prevalent spam campaigns this report varied from phishes, to attached HTMLs that redirected users to malicious sites, to emails with malicious attachments themselves. The diversity of these spam campaigns, and their targets, shows how botnets continue to serve the needs of their underground customers. Two emails showcased in the report use money transfers as social engineering. In both cases, HTML files were attached that contained malicious, obfuscated javascript. When executed, end users would be redirected to malicious sites.

Over 30% of our newly covered vulnerabilities continued to be exploited, an ongoing trend that we have witnessed for well over a year. There were a total of 91 new vulnerabilities added this period, showing that hackers continue to exploit a large number of known security holes. The report breaks down these vulnerabilities by severity, the majority of them being rated ‘High’. This gives an idea of scope, severity and in the-wild-activity. In itself, this reflects the importance of quickly patching security holes as fixes become available – on top of having IPS detection. Even with proper patch management in place, all it takes is one zero-day vulnerability to be exploited (even in low volume) to potentially cause a significant impact. For an example in July, look no further than the Stuxnet attacks (read our FAQ here). While the attack is under investigation, the fact that a trojan associated with the exploit was seemingly developed to target industrial control systems underscores this point. Further, this is also a good example of how little interaction is required by the end user to become infected. The Stuxnet exploit attacked a Windows Shell vulnerability (CVE-2010-2568) to launch its attack by simply opening a folder (thus viewing an icon). If you can remember, we saw a similar attack method with PDF files through JBIG2 image streams and Windows shell extensions back in 2009 (CVE-2009-0658): simply browsing a folder could trigger infection. Fortinet detects the vulnerability associated with the Stuxnet attack as ‘MS.Windows.Shell.LNK.Code.Execution‘, and generically detects the exploited “.LNK” payload with antivirus as ‘W32/ShellLink.a!exploit.CVE20102568‘. As of writing, there are workarounds but no official patch released from Microsoft.

‘MS.Windows.Help.Center.Protocol.Malformed.Escape.Sequence‘ was attacked in a zero-day state before Microsoft rolled out a patch for Windows Help Center (CVE-2010-1855) on July 13th. The vulnerability was publicly disclosed on June 5th, and we observed attacks happening as of June 11th. Attacks continued on a frequent basis this period, landing the attack in fourth position on our top 10 attack list. The attacks occurred through websites, however were a bit more potent considering they were not restricted to a single web browser (since they were launched through the HCP protocol handler used by all browsers). In many cases websites that serve exploits will try to fingerprint browsers and launch attack code tailored to those browsers. Like Stuxnet, this is yet another example of a zero-day vulnerability successfully attacked before a patch is made available.