Sigma rule: Suspicious BitLocker Access Agent Update Utility Execution

Rule

Title

Suspicious BitLocker Access Agent Update Utility Execution

Status

experimental

Level

high

Author

andrewdanis, Swachchhanda Shrawan Poudel (Nextron Systems)

Date

2025-10-18

File

rules/windows/process_creation/proc_creation_win_baaupdate_susp_child_process.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects the execution of the BitLocker Access Agent Update Utility (baaupdate.exe) which is not a common parent process for other processes.
Suspicious child processes spawned by baaupdate.exe could indicate an attempt at lateral movement via BitLocker DCOM & COM Hijacking.

Log source

product

windows

category

process_creation

Detection

selection:
    ParentImage|endswith: '\baaupdate.exe'
    Image|endswith:
        - '\bitsadmin.exe'
        - '\cmd.exe'
        - '\cscript.exe'
        - '\mshta.exe'
        - '\powershell_ise.exe'
        - '\powershell.exe'
        - '\regsvr32.exe'
        - '\rundll32.exe'
        - '\schtasks.exe'
        - '\wmic.exe'
        - '\wscript.exe'
condition: selection

False positives (as the rule lists them)

• Unknown

Tags

• attack.stealth
• attack.t1218
• attack.lateral-movement
• attack.t1021.003

MITRE ATT&CK ids this rule names

• T1021.003
• T1218

Related rules

• 6e8fe0a8-ba0b-4a93-8f9e-82657e7a5984 (similar)

References

• https://github.com/rtecCyberSec/BitlockMove

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules/windows/process_creation/proc_creation_win_baaupdate_susp_child_process.yml