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MediumSplunk security contentNasreddine Bencherchali +1Threat hunting

Cisco Secure Firewall - Rare Snort Rule Triggered

This analytic identifies Snort signatures that have triggered only once in the past 7 days across all Cisco Secure Firewall IntrusionEvent logs. While these rules typically do not trigger in day-to-day network…

Description

This analytic identifies Snort signatures that have triggered only once in the past 7 days across all Cisco Secure Firewall IntrusionEvent logs. While these rules typically do not trigger in day-to-day network activity, their sudden appearance may indicate early-stage compromise, previously unseen malware, or reconnaissance activity against less commonly exposed services. Investigating these outliers can provide valuable insight into new or low-noise adversary behaviors.

Detection logic

Detection requirements

Platform
PRE

The rule states no platform. This is derived from the 2 ATT&CK techniques it maps to.

Log source category
cisco_secure_firewall_threat_defense_intrusion_event

Known benign triggers

  • False positives may occur with certain rare activity. Apply additional filters where required.

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