Nimbus Manticore Expands Toolset With TWOSTROKE
Group-IB found new infrastructure and TWOSTROKE-like malware used by IRGC-linked Nimbus Manticore, indicating expanded Middle East and Europe targeting.
Group-IB reported new Tortoiseshell infrastructure spanning Europe and the Middle East and two previously undocumented tools from IRGC-linked Nimbus Manticore (UNC1549): a reverse SSH tunneling utility connecting to 172.86.98.113 on port 443, and a C++ backdoor masquerading as wtsapi32.dll with three hard-coded C2 servers. The backdoor overlaps with TWOSTROKE and supports file transfer, execution, host information gathering, and persistence. Findings build on Kaspersky's report of the NightLedger backdoor and WebSocket tunnelers BridgeHead and ArcBridge, and suggest expanded targeting beyond the Middle East into Europe.