CVE-2024-21412: 
vulnerability analysis and mitigation

CVE-2024-21412 is a security bypass vulnerability in Microsoft Windows SmartScreen that affects both Windows 10 and 11. The vulnerability was discovered in January 2024 and officially patched by Microsoft on February 13, 2024. This security flaw arises from an error in handling maliciously crafted internet shortcut files, allowing remote attackers to bypass the SmartScreen security warning dialog and deliver malicious files (Fortinet, TrendMicro).

The vulnerability has a CVSS v3.1 Base Score of 8.1 (HIGH) with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N. The flaw specifically affects Microsoft Windows SmartScreen's handling of Mark-of-the-Web (MotW) for internet shortcut files. Attackers can exploit this vulnerability through specially crafted .URL files that redirect to malicious content, effectively bypassing SmartScreen's security warnings (NVD).

When successfully exploited, CVE-2024-21412 allows attackers to bypass Microsoft Defender SmartScreen protections and deliver malicious payloads without triggering security warnings. This can lead to system compromise, data breaches, financial losses, and operational disruptions. The vulnerability has been actively exploited by multiple threat actors, including Water Hydra APT and DarkGate operators, to distribute various malware including RATs and stealers (TrendMicro).

Microsoft released an official patch for CVE-2024-21412 on February 13, 2024. Organizations are strongly advised to apply the security update. Additionally, security vendors like Trend Micro have provided virtual patching since January 17, 2024, offering protection without system reboots. Organizations should also implement robust vulnerability management processes, monitor threat intelligence feeds, and maintain rigorous patch management procedures (TrendMicro).