Threat actor

Tortoiseshell

0 mentions in 7 days · 3 in 30 days · 3 total · first seen Aug 26, 2026 · last 20d ago

Timeline3 articles

Iran-linked hackers expand infrastructure across Europe and Middle East, report says

Group-IB found Iran-linked Tortoiseshell expanding command-and-control infrastructure into the UK, Belgium, Saudi Arabia and the UAE with new malware tooling.

Group-IB researchers identified new Tortoiseshell command-and-control infrastructure, including servers named 'uk1' and 'uk2' hosted on UK IP addresses, plus systems in Belgium, Saudi Arabia and the UAE. The Iran-linked espionage group, active since at least 2018 and previously tied to the Islamic Revolutionary Guard Corps, has historically targeted defense, aerospace, technology and military organizations in the Middle East and the United States. Researchers also uncovered new malware samples, including a backdoor resembling TwoStroke that enables command execution, file theft and system reconnaissance, and a tool establishing reverse SSH tunnels to attacker-controlled servers. Group-IB assesses that the group is expanding both its geographic reach and its capabilities and ranks it among the most active Iranian APTs of 2026.

The RecordAug 26, 15:52 UTC · 20d agoThreat actor in the wild

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.

The Hacker NewsAug 26, 15:35 UTC · 20d agoThreat actor in the wild

Tortoiseshell Expands Malware Toolset With New Backdoor, SSH Tunnel

Group-IB uncovered new infrastructure linked to the Tortoiseshell threat actor, including an additional backdoor and an SSH tunneling tool.

Group-IB researchers have discovered new Tortoiseshell infrastructure, revealing an expanded backdoor and a purpose-built SSH tunneling utility. Tortoiseshell is known for targeting IT providers and telecom companies, frequently through supply-chain attacks. The expanded toolset suggests the group is investing in stealthy persistence and covert network communications.

Infosecurity MagazineAug 26, 14:30 UTC · 20d agoThreat actor

Appears with

vendor Group-IB 3 product TwoStroke 2 threat actor UNC1549 1 malware NightLedger 1 malware TwoStroke backdoor 1 organization IRGC 1 organization Islamic Revolutionary Guard Corps 1 product ArcBridge 1 product BridgeHead 1 product NightLedger 1 product SSH tunneling tool 1 threat actor Charming Kitten 1 vendor Kaspersky 1 threat actor Nimbus Manticore 1

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