IMPORTANT: No additional bug fixes or documentation updates will be released for this version. For the latest information, see the current release documentation.
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Network Connection from Binary with RWX Memory Region

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Network Connection from Binary with RWX Memory Region

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Monitors for the execution of a unix binary with read, write and execute memory region permissions, followed by a network connection. The mprotect() system call is used to change the access protections on a region of memory that has already been allocated. This syscall allows a process to modify the permissions of pages in its virtual address space, enabling or disabling permissions such as read, write, and execute for those pages. RWX permissions on memory is in many cases overly permissive, and should (especially in conjunction with an outbound network connection) be analyzed thoroughly.

Rule type: eql

Rule indices:

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

Severity: medium

Risk score: 47

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
  • Data Source: Elastic Defend
  • Data Source: Auditd Manager

Version: 3

Rule authors:

  • Elastic

Rule license: Elastic License v2

Setup

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Setup

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:

-a always,exit -F arch=b64 -S mprotect

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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sample by host.id, process.pid, process.name
  /* auditd.data.a2 == "7" translates to RWX memory region protection (PROT_READ | PROT_WRITE | PROT_EXEC) */
  [process where host.os.type == "linux" and auditd.data.syscall == "mprotect" and auditd.data.a2 == "7" and
   not process.name == "httpd"]
  [network where host.os.type == "linux" and event.type == "start" and event.action == "connection_attempted" and
   not cidrmatch(destination.ip, "127.0.0.0/8", "169.254.0.0/16", "224.0.0.0/4", "::1")]

Framework: MITRE ATT&CKTM

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