Microsoft Windows Mark of the Web (MOTW) Protection Mechanism Failure Vulnerability
What it is
Microsoft Windows Mark of the Web (MOTW) contains a protection mechanism failure vulnerability that allows an attacker to bypass MOTW-based defenses. This can result in a limited loss of integrity and availability of security features such as Protected View in Microsoft Office, which rely on MOTW tagging.
Who's affected
Affects anyone running Windows workstations or servers. In a small CPA, legal, or dental practice, Windows is typically the platform your accounting, document management, or practice management software runs on — exploitation gives an attacker access to whatever client files and credentials live on those machines.
What to do
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
CISA action deadline: October 1, 2024. Federal agencies must complete the required action by this date. For private SMBs the deadline is advisory — but treat it as a strong recommendation, especially if you handle regulated data (HIPAA, GLBA, ABA model rules).
If you don't have someone in-house to verify the patch deployed across every endpoint — or you're not sure whether you're affected — that's exactly the kind of triage we do. Book a free 20-minute triage call.
Severity
CVSS base score: 5.4 — MEDIUM
Weakness classification: CWE-693
Source
Pulled daily from the public cisagov/kev-data mirror (CC0). View the original entry on cisa.gov. CISA KEV is US-Government public-domain data; we add the SMB-vertical framing and the coping action above.