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CVE-2024-21412 is a security feature bypass vulnerability in Microsoft Windows Internet Shortcut file handling that allows specially crafted Internet Shortcut content to evade Microsoft Defender SmartScreen and related trust checks. The flaw is associated with .url/Internet Shortcut processing and has been observed in attack chains that use WebDAV-hosted content and search-ms style lures to present remote files as locally accessible content in Windows Explorer. By convincing a user to open or click the crafted shortcut, an attacker can cause Windows to retrieve and launch attacker-controlled remote content without the expected security warning flow. Public reporting also describes the issue as related to prior SmartScreen bypass behavior affecting Internet Shortcut files and notes exploitation in the wild by multiple threat actors.
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1 valid exploit after Mallory filtered fakes, detection scripts, and README-only repos.
This repository demonstrates a proof-of-concept exploit for CVE-2024-21412, targeting Microsoft Windows. The exploit leverages a chain of .url (Internet Shortcut) files and a crafted HTML file to bypass Microsoft Defender SmartScreen and achieve arbitrary code execution via a remote SMB share. The structure includes: - A 'webserver' directory with an HTML file that uses the 'search:' protocol to direct Windows Explorer to a malicious SMB share. - A 'samba-compose' directory with Docker Compose and Samba configuration files, setting up an SMB server with specific shares and user credentials. - The 'pictures' subdirectory contains chained .url files that ultimately point to a CMD script (a2.cmd) inside a ZIP archive on the SMB share. - The 'loader' directory contains the CMD script payload, which demonstrates code execution by launching calc.exe. Commented lines in the script suggest the potential for more advanced payloads, such as DLL injection. The exploit requires the attacker to run both the web server and the Samba server, and the victim to access the malicious HTML or .url files, triggering the exploit chain. The endpoints and configuration files are tailored for a local network (192.168.1.70), but could be adapted for other environments. The repository is a functional POC and does not include weaponized or highly automated payloads.
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30 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A Microsoft Windows Internet Shortcut SmartScreen bypass vulnerability mentioned as an example of another campaign using malicious MSI files.
A Microsoft Windows Defender vulnerability referenced in the group's CVE discussions.
A SmartScreen/Mark-of-the-Web bypass vulnerability historically associated in the report with WaterHydra activity; noted as patched by Microsoft in February 2024.
A Windows SmartScreen zero-day / Mark-of-the-Web bypass exploited by WaterHydra/DarkCasino in late 2023 and patched by Microsoft in February 2024.
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Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
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Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.