NailaoLocker Ransomware's 'Cheese'
Essential information
- Published
- 21/07/2025 10:27
- Modified
- 21/07/2025 10:58
- Tags
- 2025-07-21 aes-256-cbc dll side-loading multi-threaded nailaolocker ransomware sm2 cryptography windows
- Related entities
- 3 observables, 9 techniques (mitre), 1 malware
Description
NailaoLocker, a new ransomware variant targeting Windows systems, uses AES-256-CBC encryption and uniquely incorporates SM2 cryptography with hard-coded keys. It employs DLL side-loading for execution and uses I/O Completion Ports for multi-threaded file processing. The ransomware includes both encryption and decryption modes, with a built-in SM2 key pair. However, testing revealed the embedded private key fails to decrypt files properly, suggesting it may be a trap or an incomplete build. NailaoLocker's use of Chinese SM2 standards for key protection marks a departure from typical ransomware practices. While the decryption logic functions correctly with valid key material, the variant's true intent remains unclear.