Analysis Summary

A new and highly sophisticated ransomware campaign has surfaced, led by the Interlock ransomware group. This operation marks a shift in cybercriminal tactics, moving away from traditional smash-and-grab encryption attacks toward a more advanced multi-stage model. At the core of this evolution is the strategic deployment of the NodeSnake Remote Access Trojan (RAT), which enables long-term persistence within compromised networks. Interlock's methodical approach not only facilitates immediate ransom demands but also ensures continued covert access for future exploitation, suggesting a level of planning and sophistication more commonly associated with advanced persistent threats (APTs) or state-sponsored actors.

According to the Researcher, the initial access vectors exploited by Interlock include compromised Remote Desktop Protocol (RDP) credentials, phishing campaigns delivering malicious attachments, and the exploitation of unpatched internet-facing applications. These attacks are primarily aimed at mid-sized enterprises and critical infrastructure sectors such as healthcare, manufacturing, and financial services, industries where service disruption can quickly escalate pressure to meet ransom demands. Unlike traditional ransomware operators, Interlock’s emphasis appears to be on persistence and long-term access, not just one-time extortion. This strategic behavior points to a mature threat actor with the capability to conduct sustained and intelligence-driven operations.

The dual-payload nature of Interlock’s attacks complicates remediation efforts. After gaining entry and launching the ransomware, the attackers deploy the NodeSnake RAT to quietly maintain surveillance and control. While incident response teams focus on system restoration and ransomware containment, NodeSnake continues gathering intelligence and monitoring communications, often undetected. This enables the attackers to launch follow-up attacks weeks or even months later, now armed with detailed knowledge of the target's internal network. The financial fallout from such persistent access is considerable, with victims incurring recovery costs that average over $2.3 million, well above the impact of conventional ransomware incidents.

NodeSnake itself is a stealthy, persistent RAT built in Node.js, designed to blend into enterprise environments where Node.js is commonly used for legitimate operations. Upon deployment, it installs as a deceptive Windows service using a command that mimics the appearance of a system update utility, such as:

sc create "Windows Update Assistant" binpath= "C:\Windows\System32\node.exe C:\ProgramData\Microsoft\wuauclt.js" start= auto

To ensure continued presence, it employs multiple persistence mechanisms, including registry modifications, scheduled tasks, and WMI event subscriptions. These techniques provide robust long-term access that can survive standard cleanup efforts and require deep forensic investigation to fully remove. Overall, the Interlock campaign represents a dangerous escalation in ransomware strategy, combining traditional extortion with long-term espionage and sustained network compromise.

Impact

• Sensitive Data Theft
• File Encryption
• Double Extortion
• Gain Access
• Financial Loss

Indicators of Compromise

SHA1

• 8a38825ee33980a27ab6970e090a30a46226f752

• 5cc81e0df62e0d68710e14b31e2270f2ec7ed166

• 1cb6a93e6d2d86d3479a1ea59f7d5b258f1c5c53

• 2b681481488d4027736c94057c28929fd9f95d9b

URL

• http://23.95.182.59/31279geuwtoisgdehbiuowaehsgdb/cht
• https://apple-online.shop/ChromeSetup.exe

Remediation

• Block all threat indicators at your respective controls.
• Search for indicators of compromise (IOCs) in your environment utilizing your respective security controls.
• Disconnect compromised machines from the network to prevent the spread of both ransomware and the NodeSnake RAT.
• Investigate for signs of persistent RAT activity such as unusual services, scripts, scheduled tasks, registry changes, and WMI event subscriptions.
• Uninstall Node.js from systems where it is not needed to reduce the risk of abuse by malware like NodeSnake.
• Disable unused RDP services, enforce strong passwords, enable multi-factor authentication (MFA), and restrict access via VPN or IP allowlists.
• Regularly apply security updates to all internet-facing applications and systems to prevent exploitation of known vulnerabilities.
• Identify and remove suspicious services like fake “Windows Update Assistant” entries used to disguise malware installations.
• Continuously scan for indicators of persistence including suspicious registry keys, startup items, and WMI event subscriptions.
• Format and reinstall compromised machines to ensure complete removal of deeply embedded malware components.
• Change all potentially exposed passwords and rotate administrative credentials across the network.
• Use advanced EDR solutions to detect and block malicious behavior, lateral movement, and RAT communications.
• Divide networks to contain breaches and prevent malware from easily propagating across the environment.
• Use email filters to block phishing attempts and train employees to recognize suspicious messages and attachments.
• Maintain secure, offline, and immutable backups that can be restored during a ransomware event without reinfection risk.
• Notify relevant regulatory authorities and, if applicable, law enforcement or national cybersecurity agencies.