CVE-2024-38217: Windows Mark of the Web security feature bypass

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 17 September 2026. Confidence: medium.

high priorityIt is a known-exploited security feature bypass in a ubiquitous platform, though the CVSS impact is limited to low integrity and availability.

What it is

Windows Mark of the Web (MOTW) fails to properly apply its protection mechanism, allowing the reputation-based warning that normally accompanies files downloaded from the internet to be bypassed. Because MOTW feeds SmartScreen, Office macro blocking and other trust decisions, a bypass weakens a core defense layer across supported Windows client and server versions.

Impact

An attacker can get a malicious file to open without the MOTW warning or the restrictions that depend on it, increasing the chance a user runs untrusted content. The CVSS vector rates only low integrity and availability impact, so the direct gain is bypassing a security control rather than code execution by itself.

Attack surface

Reached over the network with no privileges required, but user interaction is required (AV:N/AC:L/PR:N/UI:R), consistent with a user opening or handling a crafted file. No affected file types or delivery channels are specified in the record.

Exploitation

Listed in CISA KEV with a 2024-10-01 remediation due date, and a third-party reference is tagged Exploit, indicating exploitation in the wild. EPSS is about 10 percent for 30 days (95th percentile), and no ransomware campaign use is recorded.

What to do

• Apply the Microsoft September 2024 security update for CVE-2024-38217 on all affected Windows client and server versions.
• Follow the CISA KEV required action: apply vendor mitigations or discontinue use of the product where mitigations are unavailable.
• Reduce reliance on MOTW alone by enforcing SmartScreen, Attack Surface Reduction rules and macro-blocking policies, and by restricting execution of files from untrusted locations.
• Limit user ability to open untrusted downloads and attachments, and monitor for files that execute without expected MOTW or Zone.Identifier tagging.

Detection

• Alert on processes that execute files lacking the Zone.Identifier alternate data stream or MOTW tag when policy expects it.
• Monitor for Office or script host processes spawning from user download or temp directories, which may indicate MOTW bypass.
• Hunt for files where the Zone.Identifier stream is present but malformed, truncated or stripped compared with expected download behavior.
• Correlate SmartScreen or Defender warning suppression events with subsequent execution of newly downloaded binaries.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.