Upatre.SMJ a Malware Hides in encrypted PNG Image

July 7, 2015

The Dell Sonicwall Threats Research team observed reports of a New Malware family named GAV: Upatre.SMJ actively spreading in the wild. This time attackers used a dropper to download the original Malware that hides in Image (encrypted PNG) files to avoid detection by Firewalls.

Infection Cycle:

The Malware uses the following icon:


  • 051e79a2d44a8dba92e98ae9c4be2399 - Major Executable


  • 88ff4cfd4154c9b112a963700dfcd560 - Image PNG file

The Malware adds the following files to the system:

  • Malware.exe

    • %Temp%tzojedox.exe

    • %Temp%TZ9D-23.txt

  • Tzojedox.exe

    • %Temp%kiuwken.exe

    • %Temp%TZ9D-23.txt

  • Kiuwken.exe

    • C:WINDOWSenCSuFWrQQsXBxp.exe

The Malware adds the following key to the Windows registry to ensure persistence upon reboot:

Once the computer is compromised, the malware copies its own executable file to Temp folder.

The file tzojedox.exe is dropped after malware launches on the target system, the malware tries to download PNG encrypted files from its own C&C server such as following domains:

Here is an example of encrypted PNG file:

The malware tries to retrieves your computer name, version of your windows and your IP address then its transfers information to its own C&C server such as following IPs:

Command and Control (C&C) Traffic

Upatre.SMJ performs C&C communication over 443 and 80 ports. The malware sends your system information to its own C&C server via following format, here are some examples:

We have been monitoring varying hits over the past few days for the signature that blocks this threat:

SonicWALL Gateway AntiVirus provides protection against this threat via the following signature:

  • GAV: Upatre.SMJ (Trojan)