Infection Vectors
Since we detected the first CryptoWall 2.0 variant with our WildFire engine on September 29, we’ve seen over 85,000 separate attacks attempting to deliver the malware. The majority of these have come through e-mails with executable attachments, sometimes contained in .zip files. Most of the e-mail attacks used fake invoice, fax and voicemail themes with attachments named like the following:
- Complaint_IRS-Id-12839182.scr
- fax00415741732781728.scr
- VOICE387-778-3454.zip
- CH_Import_Information.exe
In the last week we’ve seen the attack vectors evolve to contain exploit kits as well. On October 19, the Kafeine posted a
blog discussing the inclusion of CVE-2014-0556 in the Nuclear Pack exploit kit, which was installing CryptoWall 2.0.
Yesterday we picked up an e-mail campaign pretending to be a fax report that carried a .zip attachment with a PDF inside. The
PDF exploits CVE-2013-2729 to download a binary which also installed CryptoWall 2.0.