LNK Stomping Mark-of-the-Web Bypass in Windows

Successful exploitation allows an attacker to bypass Windows Mark-of-the-Web protections on a crafted file. This can suppress or evade security controls that rely on MotW, including Windows Attachment Services prompts and SmartScreen Application Reputation checks, thereby increasing the likelihood that a victim will open or execute malicious content without the normal warning flow. The vulnerability does not by itself provide direct code execution or privilege escalation, but it materially reduces a key trust boundary and can be used as an initial access or delivery enabler in broader attack chains, including campaigns intended to bypass protections around malicious documents or payload delivery.

Until patches are fully deployed, reduce exposure by blocking or tightly controlling delivery and execution of Internet-originated .LNK and other untrusted files, especially from email, web downloads, archives, and network shares. Enforce attachment filtering, restrict shortcut-file execution where operationally feasible, and use application control policies such as WDAC or AppLocker to limit execution of untrusted content. Additional mitigations include disabling automatic handling paths that permit user interaction with attacker-supplied shortcut files, monitoring for suspicious explorer.exe activity involving overwriting or creation of LNK files, and using endpoint protections to detect MotW evasion and suspicious post-delivery execution chains.

Apply Microsoft's September 2024 security updates that address CVE-2024-38217 on affected Windows systems. Because the issue affects Windows broadly, organizations should ensure the relevant cumulative/security updates are deployed across supported client and server versions, including newer releases noted as affected in the source material. Standard validation should include confirming that MotW is preserved and enforced for downloaded or Internet-originated shortcut and related files after patch deployment.