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LNK File Weaponization Jumps 50%, Powering Four Main Malware Variants

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Attackers are increasingly exploiting the flexibility of Windows shortcut (.lnk) files, turning them into potent weapons for malware delivery.

According to recent telemetry, detected malicious LNK samples soared from 21,098 in 2023 to an alarming 68,392 in 2024 a spike of over 50%.

A technical investigation of 30,000 recent samples has revealed a sophisticated threat landscape, with LNK-based malware falling into four primary categories: exploit execution, file-on-disk execution, in-argument script execution, and overlay execution.

How LNK Files Are Abused

Windows LNK files, designed to provide quick access to files, folders, or applications, have become an attractive target for cybercriminals.

Examples of icons for Windows LNK files.

Their ability to execute content, conceal true file types, and use misleading icons makes them ideal for social engineering.

Malicious actors exploit this by crafting shortcut files that appear legitimate often masquerading as documents or trusted application links enticing users to click and inadvertently trigger malware.

At the core of LNK exploitation are three structural fields: LINKTARGET_IDLIST, RELATIVE_PATH, and COMMAND_LINE_ARGUMENTS.

Analysis shows that over 99% of malicious LNK samples leverage the target resolution field, with the relative path and command-line arguments also commonly abused to stealthily execute payloads or commands.

Properties of a malicious LNK sample.

These shortcuts may point directly to malware, use system tools as proxies to launch embedded threats, or pass complex scripts as arguments for interpreters like PowerShell or cmd.exe, often employing obfuscation to hinder detection.

Overlay execution marks a newer trend, where attackers append encoded or script-based payloads beyond the ‘legitimate’ end of an LNK file.

By combining this with clever command-line extraction such as using findstr, mshta.exe, or encoded PowerShell commands the malware can decode and execute embedded scripts or binaries.

Some variants exploit system vulnerabilities directly, such as the infamous CVE-2010-2568, using malformed header fields to trigger OS-level exploits simply by browsing to an infected folder.

Protection and Detection Strategies

According to the Report, LNK weaponization is now so prevalent that both enterprises and end-users need to be vigilant.

Users are advised to examine shortcut file properties closely right-clicking and checking if the target path or command-line appears suspicious.

Familiar icons and trusted names offer little assurance, as attackers consistently camouflage malicious shortcuts.

Palo Alto Networks and its partners in the Cyber Threat Alliance are responding with enhanced detection and defense measures.

Their next-generation firewalls, Prisma Access, and Cortex XDR products leverage cloud-delivered services and real-time machine learning to detect suspicious LNK patterns and block associated exploits, including those targeting legacy vulnerabilities.

Organizations suspecting compromise are urged to contact specialist incident response teams.

Indicators of Compromise (IOCs)

No.SHA256 Hash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