Blackbyte Ransomware

Description Summary

Ransomware. Uses dropper written in JavaScript to deploy a .NET payload.

Threat Actor

Assessed linked to Conti/Wizard Spider (MITRE G1043); exploits ProxyShell/ProxyLogon and ESXi CVE-2024-37085; JavaScript dropper → .NET payload.

Technical Indicators

Encryption Extension
.blackbyte
Encryption Algorithm
AES (early: shared key; later unique per-victim keys) + RSA
Ransom Note Name
BlackByte_restoremyfiles.hta / BB_Readme_[ID].txt
Targeted Industries
Critical infrastructure, Manufacturing, Government
First Seen
July 2021
Last Seen
Active (Conti/Wizard Spider lineage)
Geographical Location
United States and worldwide

MITRE ATT&CK Matrix

Tactic TTP Technique Name
Impact x 2 T1486 Data Encrypted for Impact
T1490 Inhibit System Recovery
Exfiltration x 1 T1567 Exfiltration Over Web Service (leak site)
Initial Access x 2 T1190 Exploit Public-Facing Application
T1078 Valid Accounts