SMTP on Port 26/TCPedit
This rule detects events that may indicate use of SMTP on TCP port 26. This port is commonly used by several popular mail transfer agents to deconflict with the default SMTP port 25. This port has also been used by a malware family called BadPatch for command and control of Windows systems.
Rule type: query
Rule indices:
- packetbeat-*
- logs-network_traffic.*
Severity: low
Risk score: 21
Runs every: 5m
Searches indices from: now-9m (Date Math format, see also Additional look-back time)
Maximum alerts per execution: 100
References:
Tags:
- Tactic: Command and Control
- Domain: Endpoint
- Use Case: Threat Detection
Version: 102
Rule authors:
- Elastic
Rule license: Elastic License v2
Rule queryedit
event.dataset: network_traffic.flow and network.transport:tcp and (destination.port:26 or (event.dataset:zeek.smtp and destination.port:26))
Framework: MITRE ATT&CKTM
-
Tactic:
- Name: Command and Control
- ID: TA0011
- Reference URL: https://attack.mitre.org/tactics/TA0011/
-
Tactic:
- Name: Exfiltration
- ID: TA0010
- Reference URL: https://attack.mitre.org/tactics/TA0010/
-
Technique:
- Name: Exfiltration Over Alternative Protocol
- ID: T1048
- Reference URL: https://attack.mitre.org/techniques/T1048/