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Interlock is a financially motivated double-extortion ransomware operation active since at least late 2024. The group steals data prior to encryption and operates a Tor-based leak site to pressure victims through public exposure and regulatory consequences. Victimology includes healthcare, education, government, manufacturing, engineering, construction, and other enterprise and critical-infrastructure organizations in North America and Europe.
Interlock has been observed targeting both Windows and FreeBSD/ESXi environments. Its ransomware tooling includes Windows and ELF encryptors, and reporting links the operation to pre-encryption data theft, victim-specific negotiation workflows, and multi-stage intrusions. On Windows, Interlock has been associated with scheduled-task persistence, event-log clearing, and options to encrypt selected files or directories. Across reporting, the operation is consistently characterized as using encryption plus exfiltration for extortion.
The broader Interlock intrusion toolkit includes custom remote-access malware and credential-access tooling. A backdoor family known as NodeSnake has been associated with the operation in JavaScript, Java, and native Windows variants, providing encrypted WebSocket command and control, shell access, command execution, file transfer, SOCKS5 proxying, self-update, and self-delete. Native variants have also been reported with anti-debugging, DLL execution, and thread-hijacking functionality. Interlock activity has additionally included an NTLM credential theft component, use of ConnectWise ScreenConnect for redundant remote access, PowerShell-based host and network reconnaissance, reverse-proxy infrastructure for traffic laundering, and a memory-resident Java backdoor or web shell used for fileless persistence and post-exploitation.
Initial access has been observed through multiple mechanisms. Interlock has been tied to ClickFix social-engineering lures and to exploitation of edge-facing infrastructure, including active exploitation of CVE-2026-20131 in Cisco Secure Firewall Management Center as a zero-day before public disclosure. Post-compromise activity has included extensive system discovery, collection of browser and network artifacts, use of credential- and certificate-abuse tooling, and deployment of ransomware after access is established and maintained.
Interlock has been linked in reporting to the financially motivated cluster Hive0163 and has been discussed alongside Rhysida because of overlapping tradecraft, though any deeper organizational relationship remains unconfirmed. The operation has been publicly associated with significant attacks against healthcare entities and other enterprises, reinforcing its status as an active ransomware threat with mature post-exploitation capability.
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4 CVEs Mallory has correlated with this family across public research and vendor advisories. Each row links to the full Mallory page for that vulnerability.
PrintNightmare exploit (Interlock staging)
CVE CVE-2026-20131 Network edge device vulnerability exploited by Interlock for initial access
Local privilege escalation exploit CVE-2023-36036 (JunkFiction-crypted) ... CVE CVE-2023-36036 Local privilege escalation exploit used by Interlock and ModeloRAT operators
Interlock ... concealed ... through the custom Hotta Killer evasion tool, which harnesses a zero-day flaw in the legitimate gaming anti-cheat driver GameDriverx64.sys, tracked as CVE-2025-61155, as part of a Bring Your Own Vulnerable Driver attack. ... kernel termination of security software prior to encryption activities.
3 distinct threat actors attributed by public researchers. Open in Mallory to see the full evidence chain and overlapping campaigns.
The Rhysida and Interlock groups, which are known to attack healthcare and other critical infrastructure, have similar TTPs and encryption binaries, leading to some speculation of a connection between the two groups.
Amazon’s threat intelligence teams have uncovered a new cyber campaign linked to the Interlock ransomware group... The recovered malware and artifacts were attributed to the Interlock ransomware family based on several consistent indicators.
The e-crime group is primarily associated with a wide range of malicious tools, including NodeSnake, Interlock RAT, JunkFiction loader, and Interlock ransomware.
30 distinct techniques documented for this family, organized by ATT&CK tactic.
The agencies said they are aware of Interlock encryptors designed for Windows and Linux operating systems and have observed cyber actors obtaining access using an uncommon method of drive-by download from compromised legitimate websites, among other tactics.
Amazon threat intelligence has identified an active Interlock ransomware campaign exploiting CVE-2026-20131, a critical vulnerability in Cisco Secure Firewall Management Center (FMC) Software that could allow an unauthenticated, remote attacker to execute arbitrary Java code as root on an affected device
The Java variant adds two features... The UpdateThread creates a self-deleting scheduled task... Like the Java variant, the PE uses self-deleting scheduled tasks... A daily scheduled task runs the ransomware at 20:00 as SYSTEM.
A PowerShell-based reconnaissance script systematically collects detailed system and network information, including installed software, running services, browser data, and active connections.
The campaign centers around a flaw affecting Cisco Secure Firewall Management Center (FMC) software... It allows an unauthenticated remote attacker to execute arbitrary Java code with root privileges on affected FMC devices... Interlock had already begun exploiting this flaw as early as January 26, 2026.
The Java variant adds two features... The UpdateThread creates a self-deleting scheduled task... Like the Java variant, the PE uses self-deleting scheduled tasks... A daily scheduled task runs the ransomware at 20:00 as SYSTEM.
The Java variant adds two features... The UpdateThread creates a self-deleting scheduled task... Like the Java variant, the PE uses self-deleting scheduled tasks... A daily scheduled task runs the ransomware at 20:00 as SYSTEM.
“Interlock ransomware deploys “Hotta Killer” exploiting ... driver zero-day (CVE-2025-61155) to disable EDR/AV...”
The Windows variant imports wevtapi.dll and calls EvtClearLog to wipe Windows event logs. This is the only variant in the toolkit that clears event logs.
DELETE 0x0c fs.rmSync(__filename)... If the counter passes 40, the implant deletes itself... self-deleting scheduled task... --delete (self-delete after encryption)
A PowerShell-based reconnaissance script systematically collects detailed system and network information... and active connections.
One variant, written in JavaScript... establish[es] encrypted communication with command-and-control servers via WebSockets.
Interlock employs a Bash script that converts compromised Linux servers into HTTP reverse proxies. These proxies forward traffic to attacker-controlled systems while erasing logs every five minutes.
This triggered the next phase of the attack, where Interlock issued commands to download and execute a malicious Linux binary.
Such activity is significant as it often indicates ransomware behavior, where files are encrypted and the originals are deleted.
62 indicators attributed across vendor reports, sandbox runs, and researcher write-ups. Full values are available in Mallory.
IPs, domains, and DNS infrastructure linked to this family.
File hashes (MD5, SHA-1, SHA-256) from samples and reports.
Other indicator types observed in public reporting.
50 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Interlock4
Ransomware explicitly identified as exploiting the Cisco Secure Firewall FMC zero-day CVE-2026-20131.
Double-extortion ransomware that exfiltrates data before encryption, operates a Tor leak site, and deploys encryptors for FreeBSD/ESXi and Windows. It uses AES-256-CBC for file encryption, wraps per-file keys with RSA-4096 OAEP, appends the .interlock extension, drops !__README__!.txt ransom notes, and the Windows variant also clears event logs and establishes scheduled-task persistence.
Ransomware used in double-extortion attacks, combining file encryption with data theft. In this campaign it exploited a Cisco firewall zero-day for initial access and used a multi-stage toolkit including RATs, backdoors, reconnaissance scripts, and evasion techniques.
Match every observed IP, domain, and hash against your live telemetry.
Named campaigns wielding this family, with evidence pinned to each claim.
CVEs this family uses for access and lateral movement.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Every documented technique, ranked by evidence weight.
Reddit, Mastodon, and CTI community discussion around this family.