Network Activity Detected via cat

Last updated 5 months ago on 2025-02-04
Created 2 years ago on 2023-09-04

About

This rule monitors for the execution of the cat command, followed by a connection attempt by the same process. Cat is capable of transfering data via tcp/udp channels by redirecting its read output to a /dev/tcp or /dev/udp channel. This activity is highly suspicious, and should be investigated. Attackers may leverage this capability to transfer tools or files to another host in the network or exfiltrate data while attempting to evade detection in the process.
Tags
Domain: EndpointOS: LinuxUse Case: Threat DetectionTactic: Command and ControlData Source: Elastic DefendLanguage: eql
Severity
medium
Risk Score
47
MITRE ATT&CK™

Command and Control (TA0011)(opens in a new tab or window)

Defense Evasion (TA0005)(opens in a new tab or window)

Exfiltration (TA0010)(opens in a new tab or window)

License
Elastic License v2(opens in a new tab or window)

Definition

Rule Type
Event Correlation Rule
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
logs-endpoint.events.network*logs-endpoint.events.process*
Related Integrations

endpoint(opens in a new tab or window)

Query
sequence by host.id, process.entity_id with maxspan=1s
  [process where host.os.type == "linux" and event.type == "start" and event.action == "exec" and
   process.name == "cat" and process.parent.name in ("bash", "dash", "sh", "tcsh", "csh", "zsh", "ksh", "fish")]
  [network where host.os.type == "linux" and event.action in ("connection_attempted", "disconnect_received") and
   process.name == "cat" and not (destination.ip == null or destination.ip == "0.0.0.0" or cidrmatch(
     destination.ip, "10.0.0.0/8", "127.0.0.0/8", "169.254.0.0/16", "172.16.0.0/12", "192.0.0.0/24", "192.0.0.0/29",
     "192.0.0.8/32", "192.0.0.9/32", "192.0.0.10/32", "192.0.0.170/32", "192.0.0.171/32", "192.0.2.0/24",
     "192.31.196.0/24", "192.52.193.0/24", "192.168.0.0/16", "192.88.99.0/24", "224.0.0.0/4", "100.64.0.0/10",
     "192.175.48.0/24","198.18.0.0/15", "198.51.100.0/24", "203.0.113.0/24", "240.0.0.0/4", "::1", "FE80::/10",
     "FF00::/8"
     )
   )]

Install detection rules in Elastic Security

Detect Network Activity Detected via cat in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(opens in a new tab or window).