Elastic Security Detection Rules

Unusual Kill Signal

Last updated a month ago on 2025-07-21
Created a month ago on 2025-07-16

About

This rule detects the use of unusual kill signals, specifically kill signals in the range of 32-64, which are not commonly used in standard operations. Rootkits may leverage these signals to conduct certain actions, such as manipulating processes in unexpected ways, potentially escalating privileges or evading detection.
Tags
Domain: EndpointOS: LinuxUse Case: Threat DetectionTactic: Defense EvasionData Source: Auditd ManagerLanguage: eql
Severity
medium
Risk Score
47
MITRE ATT&CK™

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

↳ Rootkit (T1014)(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
auditbeat-*logs-auditd_manager.auditd-*
Related Integrations

auditd_manager(opens in a new tab or window)

Query
process where host.os.type == "linux" and event.action == "killed-pid" and auditd.data.syscall == "kill" and
auditd.data.a1 in (
  "21", "22", "23", "24", "25", "26", "27", "28", "29", "2a", "2b", "2c", "2d", "2e", "2f", "30",
  "31", "32", "33", "34", "35", "36", "37", "38", "39", "3a", "3b", "3c", "3d", "3e", "3f", "40",
  "41", "42", "43", "44", "45", "46", "47"
)

Install detection rules in Elastic Security

Detect Unusual Kill Signal 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).