Jigsaw Ransomware spotted in the wild (April 22, 2016)


The Dell SonicWall Threats Research team has received reports of a new Ransomware Trojan, Jigsaw (named after the fictional character) which encrypts the system files and also deletes them if the payment is not made on time.

Infection cycle:

The Trojan poses as firefox with the following properties:

The Trojan adds the following files to the filesystem:

  • %APPDATA%RoamingFrfxfirefox.exe (copy of original) [Detected as GAV: Jigsaw.A (Trojan)]

The Trojan creates the following key to the Windows registry to enable startup after reboot:

  • HKEY_CURRENT_USERSoftwareMicrosoftWindowsCurrentVersionRun “”%APPDATA%RoamingFrfxfirefox.exe””

It displays the following iconic image and the message while encrypting the files:

It starts countdown and threatens to delete the files mentioned each hour.

The trojan finds the following files on the victim’s machine and encrypts them:

It copies the filenames before encrypting at the following location:

It encrypts all the victims files listed above with .fun extension.

When trying to close the ransom window, it displays the following message:

It checks for the payment contacting the C&C server:

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

  • GAV: Jigsaw.A (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.