Rejected Federal Tax payment spam campaign (Nov 10, 2011)


SonicWALL UTM Research team observed a new spam campaign pretending to be arriving from IRS information center. It informs the user about a rejected Federal Tax payment and asks them to review the attached PDF report file for more information. The attached file is a malicious executable Trojan masquerading as a PDF file.

A sample e-mail message looks like:


The attached report file looks like:


The file if executed will perform following activity:

  • Creates a process svchost.exe and injects code into it.
  • Connects to public Google DNS Server to check for Internet connectivity and sends DNS queries to it for a list of predetermined remote servers:

  • Reports the infected machine’s information to one of the above mentioned servers via POST request:


    The decrypted version of the data being sent looks like “id:8(REMOVED)|bid:X|bv:XXX|sv:XXXX|la:X”

  • It further attempts to download malicious executable files from a remote server in Latvia:
    • 91.22(REMOVED).29/step.exe [Detected as GAV: Pakes.II_2 (Trojan)]
    • 91.22(REMOVED).29/spm.exe [Detected as GAV: Festi.C_3 (Trojan)]
  • Drops following files:
    • (All Users Temp)5328ffb60049acd7.exe [Copy of itself detected as GAV: Pakes.QUJ (Trojan)]
    • (User Temp)uhbgmrxgvk.bat [Batch file to remove previous version]
  • Deletes the original copy of the file.

SonicWALL Gateway AntiVirus provides protection against this threat via following signatures:

  • GAV: Pakes.QUJ (Trojan)
  • GAV: Festi.C_3 (Trojan)
  • GAV: Pakes.II_2 (Trojan)
Security News
The SonicWall Capture Labs Threat Research Team gathers, analyzes and vets cross-vector threat information from the SonicWall Capture Threat network, consisting of global devices and resources, including more than 1 million security sensors in nearly 200 countries and territories. The research team identifies, analyzes, and mitigates critical vulnerabilities and malware daily through in-depth research, which drives protection for all SonicWall customers. In addition to safeguarding networks globally, the research team supports the larger threat intelligence community by releasing weekly deep technical analyses of the most critical threats to small businesses, providing critical knowledge that defenders need to protect their networks.