BPF filter applied using TC

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Detects when the tc (transmission control) binary is utilized to set a BPF (Berkeley Packet Filter) on a network interface. Tc is used to configure Traffic Control in the Linux kernel. It can shape, schedule, police and drop traffic. A threat actor can utilize tc to set a bpf filter on an interface for the purpose of manipulating the incoming traffic. This technique is not at all common and should indicate abnormal, suspicious or malicious activity.

Rule type: eql

Rule indices:

  • logs-endpoint.events.*
  • endgame-*

Severity: high

Risk score: 73

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: Linux
  • Use Case: Threat Detection
  • Tactic: Execution
  • Threat: TripleCross
  • Data Source: Elastic Endgame
  • Data Source: Elastic Defend

Version: 107

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule query

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process where host.os.type == "linux" and event.type != "end" and process.executable : "/usr/sbin/tc" and process.args : "filter" and process.args : "add" and process.args : "bpf" and not process.parent.executable: "/usr/sbin/libvirtd"

Framework: MITRE ATT&CKTM