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Elastic Docs ›Elastic Security Solution [8.9] ›Detections and alerts ›Prebuilt rule reference

Suspicious Proc Pseudo File System Enumeration

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Suspicious Proc Pseudo File System Enumeration

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This rule monitors for a rapid enumeration of 25 different proc cmd, stat, and exe files, which suggests an abnormal activity pattern. Such behavior could be an indicator of a malicious process scanning or gathering information about running processes, potentially for reconnaissance, privilege escalation, or identifying vulnerable targets.

Rule type: threshold

Rule indices:

  • auditbeat-*
  • logs-auditd_manager.auditd-*

Severity: low

Risk score: 21

Runs every: 60m

Searches indices from: now-119m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

  • Data Source: Auditd Manager
  • OS: Linux
  • Use Case: Threat Detection
  • Tactic: Discovery
  • Rule Type: BBR

Version: 6

Rule authors:

  • Elastic

Rule license: Elastic License v2

Setup

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This rule requires the use of the auditd_manager integration. Auditd_manager is a tool designed to simplify and enhance the management of the audit subsystem in Linux systems. It provides a user-friendly interface and automation capabilities for configuring and monitoring system auditing through the auditd daemon. With auditd_manager, administrators can easily define audit rules, track system events, and generate comprehensive audit reports, improving overall security and compliance in the system. The following steps should be executed in order to install and deploy auditd_manager on a Linux system.

Kibana -->
Management -->
Integrations -->
Auditd Manager -->
Add Auditd Manager

Auditd_manager subscribes to the kernel and receives events as they occur without any additional configuration. However, if more advanced configuration is required to detect specific behavior, audit rules can be added to the integration in either the "audit rules" configuration box or the "auditd rule files" box by specifying a file to read the audit rules from.

For this detection rule to trigger, the following additional audit rules are required to be added to the integration:

-w /proc/ -p r -k audit_proc

Add the newly installed auditd manager to an agent policy, and deploy the agent on a Linux system from which auditd log files are desirable.

Rule query

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host.os.type:linux and event.category:file and event.action:"opened-file" and
file.path : (/proc/*/cmdline or /proc/*/stat or /proc/*/exe) and not process.name : (
  ps or netstat or landscape-sysin or w or pgrep or pidof or needrestart or apparmor_status
) and not process.parent.pid : 1

Framework: MITRE ATT&CKTM

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