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Unusual D-Bus Daemon Child Process

Elastic Stack Serverless Security

This rule detects when an unusual child process is spawned from the dbus-daemon parent process. The dbus-daemon process is a message bus system that provides a way for applications to talk to each other. Attackers may abuse this process to execute malicious code or escalate privileges.

Rule type: eql

Rule indices:

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

Severity: low

Risk score: 21

Runs every: 5m

Searches indices from: now-9m (https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#date-math[Date Math format], see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

  • Domain: Endpoint
  • OS: Linux
  • Use Case: Threat Detection
  • Tactic: Persistence
  • Tactic: Privilege Escalation
  • Tactic: Execution
  • Data Source: Elastic Endgame
  • Data Source: Elastic Defend
  • Data Source: SentinelOne
  • Resources: Investigation Guide

Version: 2

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guide

Triage and analysis

[TBC: QUOTE]
Investigating Unusual D-Bus Daemon Child Process

The D-Bus daemon is a crucial component in Linux environments, facilitating inter-process communication by allowing applications to exchange information. Adversaries may exploit this by spawning unauthorized child processes to execute malicious code or gain elevated privileges. The detection rule identifies anomalies by monitoring child processes of the D-Bus daemon, excluding known benign processes and paths, thus highlighting potential threats.

Possible investigation steps

  • Review the process details to identify the unusual child process spawned from the dbus-daemon, focusing on the process name and executable path to determine if it is known or potentially malicious.
  • Examine the command-line arguments (process.args) of the unusual child process to understand its intended function and assess if it aligns with typical usage patterns.
  • Investigate the parent process arguments (process.parent.args) to confirm whether the dbus-daemon was running in a session context or another mode that might explain the unusual child process.
  • Check the process start time and correlate it with other system events or logs to identify any related activities or anomalies occurring around the same time.
  • Look into the user context under which the unusual child process was executed to determine if it was initiated by a legitimate user or potentially compromised account.
  • Search for any network connections or file modifications associated with the unusual child process to identify potential data exfiltration or lateral movement activities.

False positive analysis

  • Known benign processes such as gnome-keyring-daemon and abrt-dbus may trigger the rule. Users can exclude these processes by adding them to the exception list in the detection rule.
  • Processes executed from common library paths like /usr/lib/ or /usr/local/lib/ are typically non-threatening. Users should review these paths and consider excluding them if they are consistently generating false positives.
  • The dbus-daemon with the --session argument is generally safe. Users can ensure this argument is included in the exception criteria to prevent unnecessary alerts.
  • Specific applications like software-properties-dbus and serviceHelper.py are known to be benign. Users should verify these applications' legitimacy in their environment and exclude them if they are frequently flagged.
  • Regularly review and update the exception list to include any new benign processes or paths that are identified over time, ensuring the rule remains effective without generating excessive false positives.

Response and remediation

  • Immediately isolate the affected system from the network to prevent potential lateral movement by the adversary.
  • Terminate any suspicious child processes spawned by the dbus-daemon that are not recognized as legitimate or necessary for system operations.
  • Conduct a thorough review of the affected system’s logs to identify any unauthorized access or changes made by the suspicious process.
  • Restore any altered or compromised system files from a known good backup to ensure system integrity.
  • Update and patch the affected system and any related software to close vulnerabilities that may have been exploited.
  • Implement stricter access controls and monitoring on the dbus-daemon to prevent unauthorized process execution in the future.
  • Escalate the incident to the security operations team for further investigation and to determine if additional systems are affected.

Setup

Setup

This rule requires data coming in from Elastic Defend.

Elastic Defend Integration Setup

Elastic Defend is integrated into the Elastic Agent using Fleet. Upon configuration, the integration allows the Elastic Agent to monitor events on your host and send data to the Elastic Security app.

Prerequisite Requirements:

  • Fleet is required for Elastic Defend.
  • To configure Fleet Server refer to the documentation.

The following steps should be executed in order to add the Elastic Defend integration on a Linux System:

  • Go to the Kibana home page and click "Add integrations".
  • In the query bar, search for "Elastic Defend" and select the integration to see more details about it.
  • Click "Add Elastic Defend".
  • Configure the integration name and optionally add a description.
  • Select the type of environment you want to protect, either "Traditional Endpoints" or "Cloud Workloads".
  • Select a configuration preset. Each preset comes with different default settings for Elastic Agent, you can further customize these later by configuring the Elastic Defend integration policy. Helper guide.
  • We suggest selecting "Complete EDR (Endpoint Detection and Response)" as a configuration setting, that provides "All events; all preventions"
  • Enter a name for the agent policy in "New agent policy name". If other agent policies already exist, you can click the "Existing hosts" tab and select an existing policy instead. For more details on Elastic Agent configuration settings, refer to the helper guide.
  • Click "Save and Continue".
  • To complete the integration, select "Add Elastic Agent to your hosts" and continue to the next section to install the Elastic Agent on your hosts. For more details on Elastic Defend refer to the helper guide.

Rule query

process where host.os.type == "linux" and event.type == "start" and event.action in ("exec", "exec_event", "start") and
process.parent.name == "dbus-daemon" and process.args_count > 1 and not (
  process.parent.args == "--session" or
  process.args in ("/usr/lib/software-properties/software-properties-dbus", "/usr/share/backintime/qt/serviceHelper.py") or
  process.name in ("dbus-daemon-launch-helper", "gnome-keyring-daemon", "abrt-dbus", "aptd", "usb-creator-helper") or
  process.executable like~ ("/usr/lib/*", "/usr/local/lib/*", "/usr/libexec/*", "/tmp/newroot/*")
)

Framework: MITRE ATT&CKTM