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++.

Sigma rule (View on GitHub)

 1title: Potential Notepad++ CVE-2025-49144 Exploitation
 2id: 933f0bb5-0681-4fe7-8a17-4e6cccbaac44
 3status: experimental
 4description: |
 5    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.
 6    This allows an attacker to execute arbitrary code with elevated privileges by placing a malicious regsvr32.exe alongside this Legitimate Notepad++ installer.
 7    The vulnerability is triggered when the installer attempts to register the NppShell.dll file, which is a component of Notepad++.    
 8references:
 9    - https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2025-49144
10    - https://x.com/NullSecurityX/status/1937444064867029179
11author: Swachchhanda Shrawan Poudel (Nextron Systems)
12date: 2025-06-26
13tags:
14    - attack.privilege-escalation
15    - attack.defense-evasion
16    - attack.t1574.008
17    - cve.2025-49144
18    - detection.emerging-threats
19logsource:
20    product: windows
21    category: process_creation
22detection:
23    selection:
24        Image|endswith: '\regsvr32.exe'
25        CommandLine|startswith: 'regsvr32 /s'
26        CommandLine|contains: '\contextMenu\NppShell.dll'
27    filter_main_legit_regsvr32:
28        Image:
29            - 'C:\Windows\System32\regsvr32.exe'
30            - 'C:\Windows\SysWOW64\regsvr32.exe'
31    condition: selection and not 1 of filter_main_*
32falsepositives:
33    - Unknown
34level: high

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