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-*
- logs-system.security*
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
- Tactic: Lateral Movement
- Data Source: Elastic Endgame
- Use Case: Vulnerability
- Data Source: Elastic Defend
Version: 107
Rule authors:
- Elastic
- Austin Songer
Rule license: Elastic License v2
Setupedit
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 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", "?:\\Program Files\\Microsoft\\Exchange Server\\Bin\\UMWorkerProcess.exe", "D:\\Exchange 2016\\Bin\\UMWorkerProcess.exe", "E:\\ExchangeServer\\Bin\\UMWorkerProcess.exe", "D:\\Exchange\\Bin\\UMWorkerProcess.exe", "D:\\Exchange Server\\Bin\\UMWorkerProcess.exe", "E:\\Exchange Server\\V15\\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/
-
Tactic:
- Name: Lateral Movement
- ID: TA0008
- Reference URL: https://attack.mitre.org/tactics/TA0008/
-
Technique:
- Name: Exploitation of Remote Services
- ID: T1210
- Reference URL: https://attack.mitre.org/techniques/T1210/