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InformationalSplunk security contentNasreddine Bencherchali +1

Cisco Secure Firewall - Repeated Malware Downloads

The following analytic detects repeated malware file downloads initiated by the same internal host (src) within a short time window. It leverages Cisco Secure Firewall Threat Defense logs and identifies `FileEvent`…

Description

The following analytic detects repeated malware file downloads initiated by the same internal host (src) within a short time window. It leverages Cisco Secure Firewall Threat Defense logs and identifies `FileEvent` events with a `SHA_Disposition` of "Malware" and `FileDirection` set to "Download". If ten or more such events occur from the same host within five minutes, this analytic will trigger. This activity may indicate the host is compromised and repeatedly retrieving malicious content either due to command-and-control, malware staging, or automation. If confirmed malicious, this behavior may represent an infection in progress, persistence mechanism, or a malicious downloader.

Detection logic

Detection requirements

Platform
ESXiLinuxmacOSNetwork DevicesWindows

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_file_event

Known benign triggers

  • False positives should be minimal here, tuning may be required to exclude known test machines or development hosts.

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