The Snatch ransomware reboots infected machines in Safe Mode so that it can bypass endpoint protection and encrypt users’ data.
In mid-October, the Sophos Managed Threat Response (MTR) team worked with an organization to remediate a ransomware infection in its network. This investigation found that a sample of Snatch ransomware had been responsible for the outbreak. It also determined that Snatch had set itself up as a service that ran during a Safe Mode boot, a technique that empowered the threat to bypass most security tools so that it could more effectively encrypt victims’ hard drives.
The attack described above wasn’t the first time that the Sophos MTR team came across Snatch. The security firm first encountered the malware, which comprises a ransomware component, data stealer, Cobalt Strike reverse-shell and other tools commonly used by pen testers, back in 2018. That being said, SophosLabs estimated that its Safe Mode feature is a relatively new capability for Snatch.
The Growing Trend of Evasive Ransomware
Snatch isn’t the first instance of ransomware employing evasive techniques. Back in July 2019, Comodo spotted samples of ShurLOckr ransomware that bypassed the security screenings of Google Drive and Microsoft Office 365 so that it could enter the cloud and potentially infect other users across an organization’s cloud platform.
That was just a few months before Intezer witnessed PureLocker using an anti-hooking technique and low-level Windows API functions in ntdll.dll to evade detection. In November 2019, Nyotron detected a Windows file system technique it named RIPlace that empowered malicious actors to circumvent most anti-ransomware measures.
How to Defend Against Snatch Ransomware
Security professionals can help their organizations defend against Snatch ransomware by feeding their network monitoring tools with the latest threat intelligence. Doing so will help security solutions stay on top of the latest evasion techniques employed by crypto-ransomware and other digital threats. Companies should also focus on protecting their endpoints by deploying patches on a timely basis and watching for anomalous activity.