Locky ransomware is in the news again with variants using different extensions for encrypted files. A couple of months ago, we blogged about the Zepto variant of Locky ransomware which used the .ZEPTO extension for encrypted files. The blog also highlighted Zepto’s executable (.EXE) payload execution with pre-defined parameters. Later, we highlight in this blog another Zepto variant that executes its main payload via DLL rather than EXE. As we continue to monitor Locky ransomware’s evolution, Netskope Threat Research Labs took a deep dive into two new variants of Locky ransomware, this time using .AESIR and .ZZZZZ extensions for encrypted files. The variants also made a few changes in the malware’s payload execution.
AESIR Variant
Netskope Threat Protection detects the AESIR variant (MD5: 3bd53e3f19c9e60d7d659134f7b6bd8b) as “Backdoor.Downloadr.ZWâ€. The detected ZIP file contains a file named â€