Interlock Ransomware Targeting Businesses

SUMMARY :

The Interlock ransomware group has been actively targeting businesses and critical infrastructures in North America and Europe since September 2024. Their ransomware employs AES-256-GCM encryption with RSA-4096 key protection, leveraging the OpenSSL library for efficient file encryption. The malware includes code obfuscation techniques and specific arguments for various behaviors. It excludes certain folders, file extensions, and files from encryption to avoid system damage. The ransomware changes file extensions to '.!NT3RLOCK' and may terminate processes during encryption. Interlock's operations involve data theft and public disclosure threats for ransom leverage. The group utilizes a Tor-based negotiation site and references legal regulations to pressure victims. To counter this threat, offsite data backups and regular recovery drills are recommended.

OPENCTI LABELS :

ransomware,data theft,interlock,europe,north america,file encryption,code obfuscation,aes-256-gcm,openssl,rsa-4096


AI COMMENTARY :

1. Overview of Interlock Ransomware

The Interlock ransomware group has emerged as a significant cyber threat against businesses and critical infrastructures in North America and Europe since September 2024. This sophisticated operation combines state-of-the-art encryption and data theft to exact maximum leverage from victims. By deploying a robust malware framework, the group swiftly encrypts valuable files, threatens public disclosure of stolen data, and demands payment under duress of legal and regulatory exposure.

2. Advanced Encryption and Obfuscation Techniques

Interlock ransomware employs AES-256-GCM encryption bolstered by RSA-4096 key protection to ensure encrypted files remain inaccessible without the private key. The malware utilizes the OpenSSL library to optimize speed and resource management during file encryption. Code obfuscation techniques conceal its true functionality, making detection and reverse engineering exceptionally challenging for security analysts.

3. Target Profiles and Geographic Focus

Since its first observed operations in September, Interlock has concentrated on enterprises across manufacturing, healthcare, finance, and energy sectors in Europe and North America. Critical infrastructure operators have been particularly vulnerable due to the potential for widespread disruption. By focusing on high-value targets with both operational downtime risks and sensitive data, the group maximizes the likelihood of ransom payment.

4. Attack Workflow and File Handling

Upon infiltration, the malware enumerates files and excludes specific folders, extensions, and system files to avoid irreparable damage to the host environment. Active processes may be terminated to release file locks, while all encrypted files are rebranded with the extension .!NT3RLOCK. This meticulous approach ensures minimal system instability and preserves the victim’s ability to interact with ransom notes and negotiation portals.

5. Extortion Methods and Negotiation Channel

Interlock’s extortion strategy combines data theft with public disclosure threats. Victim data is exfiltrated prior to encryption and held hostage. A Tor-based negotiation site offers a clandestine channel for ransom discussions. To amplify pressure, the group references relevant legal regulations and potential compliance violations, coercing organizations to pay swiftly to avoid significant regulatory fines and reputational damage.

6. Recommended Countermeasures

Defending against Interlock requires a multifaceted strategy. Organizations should maintain secure, offsite backups and test recovery processes through regular drills. Implementing robust detection tools capable of identifying obfuscated code and anomalous OpenSSL usage can help intercept attacks before encryption commences. Ongoing staff training and incident response planning are critical to minimize impact and ensure rapid recovery in the event of an intrusion.


OPEN NETMANAGEIT OPENCTI REPORT LINK!


Use public read only username and password on login page.

NOTE : Use Public READ only user credentials on login page banner.


Interlock Ransomware Targeting Businesses