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Detection rules › Sigma

Suspicious Creation of .library-ms File — Potential CVE-2025-24054 Exploit

Status
experimental
Severity
medium
Log source
product windows, category file_event
Author
Gene Kazimiarovich
Source
github.com/SigmaHQ/sigma

Detects creation of '.library-ms' files, which may indicate exploitation of CVE-2025-24054. This vulnerability allows an attacker to trigger an automatic outbound SMB or WebDAV authentication request to a remote server upon archive extraction. If the system is unpatched, no user interaction is required beyond extracting a malicious archive—potentially exposing the user's NTLMv2-SSP hash to the attacker.

MITRE ATT&CK coverage

TacticTechniques
Credential AccessT1187 Forced Authentication

Event coverage

ProviderEventTitle
SysmonEvent ID 11FileCreate

Rule body yaml

title: Suspicious Creation of .library-ms File — Potential CVE-2025-24054 Exploit
id: 5a7132c0-86db-4e6b-95c0-f0e9d7f461aa
status: experimental
description: |
    Detects creation of '.library-ms' files, which may indicate exploitation of CVE-2025-24054. This vulnerability allows an attacker to trigger an automatic outbound SMB or WebDAV authentication request to a remote server upon archive extraction.
    If the system is unpatched, no user interaction is required beyond extracting a malicious archive—potentially exposing the user's NTLMv2-SSP hash to the attacker.
references:
    - https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-24054
    - https://research.checkpoint.com/2025/cve-2025-24054-ntlm-exploit-in-the-wild/
author: Gene Kazimiarovich
date: 2025-04-20
tags:
    - detection.emerging-threats
    - attack.credential-access
    - attack.t1187   # Forced Authentication
    - cve.2025-24054
logsource:
    product: windows
    category: file_event
detection:
    selection:
        TargetFilename|endswith: '.library-ms'
        Image|endswith:
            - '\7z.exe'
            - '\winrar.exe'
            - '\explorer.exe'
    condition: selection
falsepositives:
    - Legitimate Library shortcuts under %APPDATA%\Microsoft\Windows\Libraries\ (rarely created by end-users)
    - Custom corporate scripts that programmatically generate .library-ms Files
level: medium

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    TargetFilename|endswith: '.library-ms'
    Image|endswith:
        - '\7z.exe'
        - '\winrar.exe'
        - '\explorer.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.

FieldKindValues
Imageends_with
  • \7z.exe corpus 4 (sigma 4)
  • \explorer.exe corpus 14 (sigma 14)
  • \winrar.exe corpus 6 (sigma 6)
TargetFilenameends_with
  • .library-ms