BRONZE BUTLER

Overview

BRONZE BUTLER is a cyber espionage group with likely Chinese origins that has been active since at least 2008. The group primarily targets Japanese organizations, particularly those in government, biotechnology, electronics manufacturing, and industrial chemistry.

Naming & attribution

BRONZE BUTLER is tracked under 3 names across the industry. It uses 40 documented ATT&CK techniques — more than 74% of the 174 groups tracked here. Activity attributed since at least 2008.

Distinctive techniques

Techniques this group uses that are rare across the other 173 tracked groups — these carry more signal than the near-universal ones.

• T1053.002 At — used by 3 of 174 groups
• T1550.003 Pass the Ticket — used by 3 of 174 groups

Closest groups by technique overlap

Computed from shared ATT&CK techniques. Overlap is not attribution — distinct actors converge on the same tradecraft — but a high share is a useful pivot.

• Patchwork — 20 shared techniques (33% overlap)
• MuddyWater Iran — 26 shared techniques (32% overlap)
• RedCurl — 19 shared techniques (31% overlap)
• APT39 Iran — 19 shared techniques (26% overlap)
• menuPass China — 18 shared techniques (26% overlap)
• Silence — 14 shared techniques (26% overlap)

Targets

Diplomacy · Engineering · Industrial · Infrastructure · Manufacturing · Media · Political party · Private sector

Regions

China · Japan · Russian Federation · South Korea

Capabilities

• Exploitation of public-facing / client applications — ATT&CK T1203
• Custom malware/implant development — ATT&CK: 7 attributed custom malware families

TTPs — 40 techniques across 12 tactics

Tools & malware (14)

Mimikatz · build_downer · cmd · ABK · at · BBK · schtasks · down_new · Daserf · Net · ShadowPad · Windows Credential Editor · gsecdump · Avenger

Reporting (3)

• Operation ENDTRADE: TICK’s Multi-Stage Backdoors for Attacking Industries and Stealing Classified Data — Chen, J. et al
• REDBALDKNIGHT/BRONZE BUTLER’s Daserf Backdoor Now Using Steganography — Chen, J. and Hsieh, M
• BRONZE BUTLER Targets Japanese Enterprises — Counter Threat Unit Research Team