CVE-2009-4530

Step 1: Target Identification: The attacker identifies a web server running a vulnerable version of Mongoose (2.8.0 or earlier).

Step 2: Crafting the Payload: The attacker constructs a malicious URI by appending ::$DATA to the path of a target file (e.g., http://example.com/index.html::$DATA).

Step 3: Request Submission: The attacker sends the crafted URI to the vulnerable Mongoose web server.

Step 4: Vulnerability Trigger: The Mongoose server processes the request, fails to properly sanitize the URI, and attempts to retrieve the file.

Step 5: Information Disclosure: The server, due to the lack of proper input validation, returns the source code of the requested file instead of rendering the webpage, revealing the source code to the attacker.

The vulnerability stems from a failure in Mongoose's handling of URI parsing and file serving. Specifically, the software does not properly sanitize or validate the URI before accessing the file system. Appending ::$DATA to a URI bypasses the intended file access restrictions, allowing the attacker to retrieve the raw source code of the requested file. The root cause is a lack of input validation and improper handling of NTFS alternate data streams (ADS) or similar mechanisms, depending on the underlying file system. The software likely attempts to serve the file without properly checking the URI for malicious suffixes.