Suspicious WerFault Child Process
editSuspicious WerFault Child Process
editA suspicious WerFault child process was detected, which may indicate an attempt to run via the SilentProcessExit registry key manipulation. Verify process details such as command line, network connections and file writes.
Rule type: eql
Rule indices:
- winlogbeat-*
- logs-endpoint.events.process-*
- logs-windows.*
- endgame-*
- logs-sentinel_one_cloud_funnel.*
Severity: medium
Risk score: 47
Runs every: 5m
Searches indices from: now-9m (Date Math format, see also Additional look-back time
)
Maximum alerts per execution: 100
References:
- https://www.hexacorn.com/blog/2019/09/19/silentprocessexit-quick-look-under-the-hood/
- https://www.hexacorn.com/blog/2019/09/20/werfault-command-line-switches-v0-1/
- https://github.com/sbousseaden/EVTX-ATTACK-SAMPLES/blob/master/Persistence/persistence_SilentProcessExit_ImageHijack_sysmon_13_1.evtx
- http://web.archive.org/web/20230530011556/https://blog.menasec.net/2021/01/
Tags:
- Domain: Endpoint
- OS: Windows
- Use Case: Threat Detection
- Tactic: Defense Evasion
- Tactic: Persistence
- Tactic: Privilege Escalation
- Data Source: Elastic Endgame
- Data Source: Elastic Defend
- Data Source: SentinelOne
Version: 214
Rule authors:
- Elastic
Rule license: Elastic License v2
Setup
editSetup
If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2,
events will not define event.ingested
and default fallback for EQL rules was not added until version 8.2.
Hence for this rule to work effectively, users will need to add a custom ingest pipeline to populate
event.ingested
to @timestamp.
For more details on adding a custom ingest pipeline refer - https://www.elastic.co/guide/en/fleet/current/data-streams-pipeline-tutorial.html
Rule query
editprocess where host.os.type == "windows" and event.type == "start" and process.parent.name : "WerFault.exe" and /* args -s and -t used to execute a process via SilentProcessExit mechanism */ (process.parent.args : "-s" and process.parent.args : "-t" and process.parent.args : "-c") and not process.executable : ("?:\\Windows\\SysWOW64\\Initcrypt.exe", "?:\\Program Files (x86)\\Heimdal\\Heimdal.Guard.exe")
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Defense Evasion
- ID: TA0005
- Reference URL: https://attack.mitre.org/tactics/TA0005/
-
Technique:
- Name: Masquerading
- ID: T1036
- Reference URL: https://attack.mitre.org/techniques/T1036/
-
Tactic:
- Name: Persistence
- ID: TA0003
- Reference URL: https://attack.mitre.org/tactics/TA0003/
-
Technique:
- Name: Event Triggered Execution
- ID: T1546
- Reference URL: https://attack.mitre.org/techniques/T1546/
-
Sub-technique:
- Name: Image File Execution Options Injection
- ID: T1546.012
- Reference URL: https://attack.mitre.org/techniques/T1546/012/
-
Tactic:
- Name: Privilege Escalation
- ID: TA0004
- Reference URL: https://attack.mitre.org/tactics/TA0004/
-
Technique:
- Name: Event Triggered Execution
- ID: T1546
- Reference URL: https://attack.mitre.org/techniques/T1546/
-
Sub-technique:
- Name: Image File Execution Options Injection
- ID: T1546.012
- Reference URL: https://attack.mitre.org/techniques/T1546/012/