Elastic Security Detection Rules

Potential Fileless Execution via O_TMPFILE

Last updated 5 days ago on 2026-09-07
Created 5 days ago on 2026-09-07

About

This rule identifies potential fileless ELF execution where a process is launched from an anonymous temporary executable path that appears as "/#<id>" in "process.executable". This pattern may be associated with "O_TMPFILE" and "execveat" with "AT_EMPTY_PATH", which can allow execution without a normal filesystem pathname.
Tags
Domain: EndpointOS: LinuxPlatform: LinuxUse Case: Threat DetectionTactic: Defense EvasionRule Type: Event Correlation (EQL)Data Source: Auditd ManagerData Source: Elastic DefendData Source: Elastic EndgameData Source: CrowdstrikeData Source: SentinelOneLanguage: eql
Severity
high
Risk Score
73
MITRE ATT&CK™

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

↳ Masquerading (T1036)(external, opens in a new tab or window)

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

Definition

Rule Type
Event Correlation Rule
Integration Pack
Prebuilt Security Detection Rules
Index Patterns
auditbeat-*endgame-*logs-crowdstrike.fdr*logs-endpoint.events.process-*logs-sentinel_one_cloud_funnel.*logs-auditd_manager.auditd-*
Related Integrations

auditd_manager(external, opens in a new tab or window)

crowdstrike(external, opens in a new tab or window)

endpoint(external, opens in a new tab or window)

sentinel_one_cloud_funnel(external, opens in a new tab or window)

Query
text code block:
process where host.os.type == "linux" and event.type == "start" and
event.action in ("exec", "exec_event", "start", "ProcessRollup2", "executed", "process_started") and
process.executable regex """.*/\#[0-9]+.*"""

Install detection rules in Elastic Security

Detect Potential Fileless Execution via O_TMPFILE 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(external, opens in a new tab or window).