Emerging Threathighexperimental

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++.

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Launch
Swachchhanda Shrawan Poudel (Nextron Systems)Created Thu Jun 26933f0bb5-0681-4fe7-8a17-4e6cccbaac442025
Emerging Threat
Active Threat

Developed to detect an active or emerging threat. Prioritize investigation of any alerts and correlate with threat intelligence.

Log Source
WindowsProcess Creation
ProductWindows← raw: windows
CategoryProcess Creation← raw: process_creation

Events generated when a new process is spawned on the system. Covers command-line arguments, parent/child relationships, and process metadata.

Detection Logic
Detection Logic2 selectors
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_*
False Positives
Unknown

False positive likelihood has not been assessed. Additional context may be needed during triage.

Rule Metadata
Rule ID
933f0bb5-0681-4fe7-8a17-4e6cccbaac44
Status
experimental
Level
high
Type
Emerging Threat
Created
Thu Jun 26
Path
rules-emerging-threats/2025/Exploits/CVE-2025-49144/proc_creation_win_exploit_cve_2025_49144.yml
Raw Tags
attack.persistenceattack.privilege-escalationattack.defense-evasionattack.t1574.008cve.2025-49144detection.emerging-threats
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