IMPORTANT: No additional bug fixes or documentation updates will be released for this version. For the latest information, see the current release documentation.
« Suspicious Network Activity to the Internet by Previously Unknown Executable Suspicious PDF Reader Child Process »
Elastic Docs ›Elastic Security Solution [8.6] ›Detections and alerts ›Prebuilt rule reference

Suspicious Network Connection Attempt by Root

edit

Suspicious Network Connection Attempt by Root

edit

Identifies an outbound network connection attempt followed by a session id change as the root user by the same process entity. This particular instantiation of a network connection is abnormal and should be investigated as it may indicate a potential reverse shell activity via a privileged process.

Rule type: eql

Rule indices:

  • logs-endpoint.events.*

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: Command and Control

Version: 104

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guide

edit
## Triage and analysis
### Investigating Connection Attempt by Non-SSH Root Session
Detection alerts from this rule indicate a strange or abnormal outbound connection attempt by a privileged process.  Here are some possible avenues of investigation:
- Examine unusual and active sessions using commands such as 'last -a', 'netstat -a', and 'w -a'.
- Analyze processes and command line arguments to detect anomalous process execution that may be acting as a listener.
- Analyze anomalies in the use of files that do not normally initiate connections.
- Examine processes utilizing the network that do not normally have network communication.

Rule query

edit
sequence by process.entity_id with maxspan=1m
[network where host.os.type == "linux" and event.type == "start" and event.action == "connection_attempted" and user.id == "0" and
    not process.executable : ("/bin/ssh", "/sbin/ssh", "/usr/lib/systemd/systemd", "/usr/sbin/sshd","/usr/bin/ssh","/usr/bin/sshpass")]
[process where host.os.type == "linux" and event.action == "session_id_change" and user.id == "0" and
    not process.executable : ("/bin/ssh", "/sbin/ssh", "/usr/lib/systemd/systemd", "/usr/sbin/sshd","/usr/bin/ssh","/usr/bin/sshpass")]

Framework: MITRE ATT&CKTM

« Suspicious Network Activity to the Internet by Previously Unknown Executable Suspicious PDF Reader Child Process »