Gandcrab Ransomware actively spreading in the wild

The SonicWall Capture Labs Threat Research Team observed reports of a new variant family of Gandcrab Ransomware [Gandcrab.RSM] actively spreading in the wild.

Gandcrab Ransomware encrypts the victims files with a strong encryption algorithm until the victim pays a fee to get them back.

An example of a Script file that leads to the Gandcrab ransomware.

Infection Cycle:

The Malware adds the following files to the system:

• Malware.JS
  • %Userprofile%\ Local Settings\Temp\[Random Numbers].exe
    • Executable dropper File
  • %Userprofile%\Desktop\ CRAB-DECRYPT.txt
    • Instruction for recovery

Once the computer is compromised, the Ransomware downloads its own executable file from its own C&C server and copies into %Temp% folder and runs following commands:

While Ransomware is encrypting files, it will encrypt all files and append the .CRAB extension onto each encrypted file’s filename.

The Ransomware encrypts all personal documents and files it shows the following webpage containing a message reporting that the computer has been encrypted and to contact its developer for unlock instructions.

Command and Control (C&C) Traffic

Gandcrab performs C&C communication over HTTP protocol.

The malware sends HTTP request to its own C&C server with following formats, here is an example:

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

Sonicwall Capture Labs provides protection against this threat via the following signature:

• GAV: Gandcrab.RSM (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.