Sigma rule: HTML Help HH.EXE Suspicious Child Process

Rule

Title

HTML Help HH.EXE Suspicious Child Process

Status

test

Level

high

Author

Maxim Pavlunin, Nasreddine Bencherchali (Nextron Systems)

Date

2020-04-01

Modified

2023-04-12

File

rules/windows/process_creation/proc_creation_win_hh_html_help_susp_child_process.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects a suspicious child process of a Microsoft HTML Help (HH.exe)

Log source

product

windows

category

process_creation

Detection

selection:
    ParentImage|endswith: '\hh.exe'
    Image|endswith:
        - '\CertReq.exe'
        - '\CertUtil.exe'
        - '\cmd.exe'
        - '\cscript.exe'
        - '\installutil.exe'
        - '\MSbuild.exe'
        - '\MSHTA.EXE'
        - '\msiexec.exe'
        - '\powershell.exe'
        - '\pwsh.exe'
        - '\regsvr32.exe'
        - '\rundll32.exe'
        - '\schtasks.exe'
        - '\wmic.exe'
        - '\wscript.exe'
condition: selection

False positives (as the rule lists them)

• Unknown

Tags

• attack.execution
• attack.initial-access
• attack.stealth
• attack.t1047
• attack.t1059.001
• attack.t1059.003
• attack.t1059.005
• attack.t1059.007
• attack.t1218
• attack.t1218.001
• attack.t1218.010
• attack.t1218.011
• attack.t1566
• attack.t1566.001

MITRE ATT&CK ids this rule names

• T1047
• T1059.001
• T1059.003
• T1059.005
• T1059.007
• T1218
• T1218.001
• T1218.010
• T1218.011
• T1566
• T1566.001

References

• https://www.trustwave.com/en-us/resources/blogs/spiderlabs-blog/chm-badness-delivers-a-banking-trojan/
• https://github.com/elastic/protections-artifacts/commit/746086721fd385d9f5c6647cada1788db4aea95f#diff-27939090904026cc396b0b629c8e4314acd6f5dac40a676edbc87f4567b47eb7
• https://www.ptsecurity.com/ww-en/analytics/pt-esc-threat-intelligence/higaisa-or-winnti-apt-41-backdoors-old-and-new/
• https://www.zscaler.com/blogs/security-research/unintentional-leak-glimpse-attack-vectors-apt37

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_hh_html_help_susp_child_process.yml