Threats Tagged 'file encryption'

A detailed technical analysis confirms that Kyber ransomware implements genuine hybrid post-quantum cryptography rather than mere branding. The Rust-based Windows variant encrypts files using AES-256-CTR with Kyber1024 and X25519 for key protection, appending a fixed 0x744-byte trailer containing encrypted metadata. Instrumented analysis validated the cryptographic implementation through fixture decryption but found no practical recovery path from the sample alone. The encryptor targets multiple file types, deploys standard recovery-inhibition techniques, and marks encrypted files with a .#~~~ extension. A separate ESXi variant was found to use different cryptography despite similar branding. As of April 2026, one victim was publicly listed: a large American defense contractor and IT services provider.

NightSpire ransomware, first discovered in February 2025, presents a categorization challenge regarding whether it operates as Ransomware-as-a-Service (RaaS). Analysis of two incidents from December 2025 and March 2026 reveals significant variations in tactics, techniques, and procedures between attacks. The March 2026 incident involved threat actors installing Chrome Remoting Desktop and AnyDesk for persistence, using Everything and 7Zip for data staging, MEGASync for exfiltration, and deploying VMWare Workstation and WPS Office. The attacker accessed systems via RDP days before detection. Comparison with the December 2025 incident shows evolution in the ransomware encryptor, including modified ransom note filenames and contents. These variations in TTPs and indicators suggest either operational evolution or involvement of multiple affiliates, demonstrating that ransomware indicators aren't consistent across campaigns.

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.

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