LongPathsEnabled - registry modified

Last updated on:

Rule name

Rule type

Log sources

MITRE ATT&CK tags

Severity

LongPathsEnabled - registry modified

Standard

Windows, Sysmon

Persistence: Modify Registry (T1112)

Trouble

About the rule

Rule Type

Standard

Rule Description

The following analytic detects a modification to the Windows registry setting "LongPathsEnabled, (path: HKLM\SYSTEM\ControlSet001\Control\FileSystem\LongPathsEnabled, value: 0x00000001)" which allows file paths longer than 260 characters. This activity is significant because adversaries, including malware like BlackByte, exploit this setting to bypass file path limitations, potentially aiding in evasion techniques. If confirmed malicious, this modification could facilitate the execution of long-path payloads, aiding in persistence and further system compromise.

Why this rule?

Enabling LongPathsEnabled removes Windows' default 260-character path limit, a restriction that certain malware families — most notably BlackByte ransomware — exploit to deploy payloads in deeply nested directories that evade traditional security scanning. Adversaries modify this registry key to bypass file path limitations, aiding in both defense evasion and persistence. Detecting this change is important because it signals a possible early-stage attack setup and warrants immediate investigation of the modifying process.

Severity

Trouble

Rule journey

Attack chain scenario

Initial Access via spear-phishing or brute-forced RDP -> Execution via PowerShell/CMD silent registry write -> Defense Evasion via deeply nested paths bypassing security tools -> Persistence via run key/scheduled task surviving remediation

Impact

Modification of this registry key can enable adversaries to deploy long-path payloads that evade security controls, facilitating persistent access and further compromise of the affected system.

Rule Requirement

Prerequisites

Install Sysmon from Microsoft Sysinternals with registry event monitoring enabled.

Criteria

Action1: actionname = "Registry Event" AND ( OBJECTNAME contains "Control\FileSystem" ) AND ( OBJECTNAME endswith "LongPathsEnabled" OR OBJECTVALUENAME = "LongPathsEnabled" ) AND ( CHANGES = "1" OR INFORMATION = "DWORD (0x00000001)" ) select Action1.HOSTNAME,Action1.MESSAGE,Action1.PROCESSNAME,Action1.OBJECTNAME,Action1.OBJECTVALUENAME,Action1.ACCESSES,Action1.USERNAME,Action1.DOMAIN,Action1.PREVVAL,Action1.CHANGES,Action1.INFORMATION

Detection

Execution Mode

realtime

Log Sources

Windows

MITRE ATT&CK

Persistence: Modify Registry (T1112)

Future actions

Known False Positives

Administrators may toggle this feature, which can result in false positives.

Next Steps

  1. Identification: Identify the specific registry key modification and the process or user account responsible for the change.
  2. Analysis: Verify whether the modification was made by a legitimate administrator or an unauthorized process, and check for associated suspicious activity.
  3. Response: Revert the registry key to its original value and investigate any payloads or processes that may have leveraged the long-path capability.

Mitigation

ID

Mitigation

Description

M1024

Restrict Registry Permissions

Ensure proper permissions are set for Registry hives to prevent users from modifying keys for system components that may lead to privilege escalation.