Microsoft Exchange Server UM Spawning Suspicious Processesedit
Identifies suspicious processes being spawned by the Microsoft Exchange Server Unified Messaging (UM) service. This activity has been observed exploiting CVE-2021-26857.
Rule type: eql
Rule indices:
- logs-endpoint.events.*
- winlogbeat-*
- logs-windows.*
- endgame-*
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:
Tags:
- Domain: Endpoint
- OS: Windows
- Use Case: Threat Detection
- Tactic: Initial Access
- Data Source: Elastic Endgame
- Use Case: Vulnerability
- Data Source: Elastic Defend
Version: 104
Rule authors:
- Elastic
- Austin Songer
Rule license: Elastic License v2
Investigation guideedit
Rule queryedit
process where host.os.type == "windows" and event.type == "start" and
process.parent.name : ("UMService.exe", "UMWorkerProcess.exe") and
not process.executable :
("?:\\Windows\\System32\\werfault.exe",
"?:\\Windows\\System32\\wermgr.exe",
"?:\\Program Files\\Microsoft\\Exchange Server\\V??\\Bin\\UMWorkerProcess.exe",
"D:\\Exchange 2016\\Bin\\UMWorkerProcess.exe",
"E:\\ExchangeServer\\Bin\\UMWorkerProcess.exe")
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Initial Access
- ID: TA0001
- Reference URL: https://attack.mitre.org/tactics/TA0001/
-
Technique:
- Name: Exploit Public-Facing Application
- ID: T1190
- Reference URL: https://attack.mitre.org/techniques/T1190/