Process Activity via Compiled HTML File
editProcess Activity via Compiled HTML File
editCompiled HTML files (.chm) are commonly distributed as part of the Microsoft
HTML Help system. Adversaries may conceal malicious code in a CHM file and
deliver it to a victim for execution. CHM content is loaded by the HTML Help
executable program (hh.exe).
Rule type: query
Rule indices:
- winlogbeat-*
- logs-endpoint.events.*
- logs-windows.*
Severity: low
Risk score: 21
Runs every: 5 minutes
Searches indices from: now-9m (Date Math format, see also Additional look-back time)
Maximum alerts per execution: 100
Tags:
- Elastic
- Host
- Windows
- Threat Detection
- Execution
Version: 7 (version history)
Added (Elastic Stack release): 7.6.0
Last modified (Elastic Stack release): 7.12.0
Rule authors: Elastic
Rule license: Elastic License v2
Potential false positives
editThe HTML Help executable program (hh.exe) runs whenever a user clicks a compiled help (.chm) file or menu item that opens the help file inside the Help Viewer. This is not always malicious, but adversaries may abuse this technology to conceal malicious code.
Rule query
editevent.category:process and event.type:(start or process_started) and process.name:hh.exe
Threat mapping
editFramework: MITRE ATT&CKTM
-
Tactic:
- Name: Execution
- ID: TA0002
- Reference URL: https://attack.mitre.org/tactics/TA0002/
-
Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
-
Technique:
- Name: Signed Binary Proxy Execution
- ID: T1218
- Reference URL: https://attack.mitre.org/techniques/T1218/
Rule version history
edit- Version 7 (7.12.0 release)
-
- Formatting only
- Version 6 (7.11.2 release)
-
- Formatting only
- Version 5 (7.11.0 release)
-
- Formatting only
- Version 4 (7.10.0 release)
-
-
Updated query, changed from:
event.code:1 and process.name:hh.exe
-
- Version 3 (7.9.0 release)
-
- Formatting only
- Version 2 (7.7.0 release)
-
- Formatting only