Analyzing and Reverse Engineering Malicious LNK Files

 

An LNK file is a Windows shortcut (Shell Link) that provides quick access to another file, folder, application, or website. It acts as a pointer to the original target and is usually identified by a small arrow on its icon and the .lnk extension, although the extension is hidden by default in File Explorer. Created by users for convenience, these files contain information that allows Windows to locate and open the linked item, making it appear as if the shortcut is the actual item. They can also be abused by malicious actors to deliver malware by hiding scripts or payloads inside the shortcut. 

Threat actors abuse LNK files for many reasons. One of them is that LNK files are easy to create and customize. It is simple to change the shortcut’s icon to mimic a PDF or another common document type, making the file appear harmless to the victim. LNK files can also execute commands or launch hidden scripts in the background, which allows attackers to run PowerShell, download payloads, or start malicious processes without raising immediate suspicion. Because Windows treats LNK files as trusted system components, they often bypass basic security controls and can be used to deliver malware in phishing emails, removable media attacks, or compromised archives.

Some researchers investigate malicious LNK files by simply right‑clicking the file, opening Properties, and checking the Target field. However, this approach is unreliable because the characters shown in the Target field are limited, which means important parts of the command may be hidden or truncated. To properly analyze a malicious LNK file, it is better to use a dedicated tool. In our case, we will use a tool called lnk_parser.exe to extract and review all of the embedded metadata and command execution details.

For a quick overview, you can run the tool with the basic command lnk_parser.exe <sample.lnk>, which displays the general results directly in the console. However, if you need an HTML report for documentation or analysis, you can generate one using lnk_parser.exe -w <sample.lnk>. This produces a detailed, formatted report that summarizes all relevant information about the malicious LNK file.

Enjoy :) .