Detection rules › Sigma
Potential Notepad++ CVE-2025-49144 Exploitation
Detects potential exploitation of CVE-2025-49144, a local privilege escalation vulnerability in Notepad++ installers (v8.8.1 and prior) where the installer calls regsvr32.exe without specifying the full path. This allows an attacker to execute arbitrary code with elevated privileges by placing a malicious regsvr32.exe alongside this Legitimate Notepad++ installer. The vulnerability is triggered when the installer attempts to register the NppShell.dll file, which is a component of Notepad++.
MITRE ATT&CK coverage
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 1 | Process creation |
| Security-Auditing | Event ID 4688 | A new process has been created. |
Rule body yaml
title: Potential Notepad++ CVE-2025-49144 Exploitation
id: 933f0bb5-0681-4fe7-8a17-4e6cccbaac44
status: experimental
description: |
Detects potential exploitation of CVE-2025-49144, a local privilege escalation vulnerability in Notepad++ installers (v8.8.1 and prior) where the installer calls regsvr32.exe without specifying the full path.
This allows an attacker to execute arbitrary code with elevated privileges by placing a malicious regsvr32.exe alongside this Legitimate Notepad++ installer.
The vulnerability is triggered when the installer attempts to register the NppShell.dll file, which is a component of Notepad++.
references:
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-49144
- https://x.com/NullSecurityX/status/1937444064867029179
author: Swachchhanda Shrawan Poudel (Nextron Systems)
date: 2025-06-26
tags:
- attack.persistence
- attack.privilege-escalation
- attack.execution
- attack.stealth
- attack.t1574.008
- cve.2025-49144
- detection.emerging-threats
logsource:
product: windows
category: process_creation
detection:
selection:
Image|endswith: '\regsvr32.exe'
CommandLine|startswith: 'regsvr32 /s'
CommandLine|contains: '\contextMenu\NppShell.dll'
filter_main_legit_regsvr32:
Image:
- 'C:\Windows\System32\regsvr32.exe'
- 'C:\Windows\SysWOW64\regsvr32.exe'
condition: selection and not 1 of filter_main_*
falsepositives:
- Unknown
level: high
Stages and Predicates
Stage 0: condition
selection and not 1 of filter_main_*Stage 1: selection
selection:
Image|endswith: '\regsvr32.exe'
CommandLine|startswith: 'regsvr32 /s'
CommandLine|contains: '\contextMenu\NppShell.dll'
Stage 2: not filter_main_legit_regsvr32
filter_main_legit_regsvr32:
Image:
- 'C:\Windows\System32\regsvr32.exe'
- 'C:\Windows\SysWOW64\regsvr32.exe'
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
Image | eq | C:\Windows\SysWOW64\regsvr32.exe |
Image | eq | C:\Windows\System32\regsvr32.exe |
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
CommandLine | match |
|
CommandLine | starts_with |
|
Image | ends_with |
|