LoFP / this search will return false positives for any legitimate traffic captures by network administrators.

Techniques

• T1020
• T1020.001
• T1200
• T1498

Sample rules

Detect Traffic Mirroring

• source: splunk
• technicques:
  • T1200
  • T1020
  • T1498
  • T1020.001

Description

The following analytic detects the initiation of traffic mirroring sessions on Cisco network devices. It leverages logs with specific mnemonics and facilities related to traffic mirroring, such as “ETH_SPAN_SESSION_UP” and “PKTCAP_START.” This activity is significant because adversaries may use traffic mirroring to exfiltrate data by duplicating and forwarding network traffic to an external destination. If confirmed malicious, this could allow attackers to capture sensitive information, monitor network communications, and potentially compromise the integrity and confidentiality of the network.

Detection logic

`cisco_networks` (facility="MIRROR" mnemonic="ETH_SPAN_SESSION_UP") OR (facility="SPAN" mnemonic="SESSION_UP") OR (facility="SPAN" mnemonic="PKTCAP_START") OR (mnemonic="CFGLOG_LOGGEDCMD" command="monitor session*") 
| stats min(_time) AS firstTime max(_time) AS lastTime count BY host facility mnemonic 
| `security_content_ctime(firstTime)`
|`security_content_ctime(lastTime)` 
| `detect_traffic_mirroring_filter`