Yeswiki Path Traversal vulnerability allows arbitrary read of files

Summary

The squelette parameter is vulnerable to path traversal attacks, enabling read access to arbitrary files on the server. The payload ../../../../../../etc/passwd was submitted in the squelette parameter. The requested file was returned in the application's response.

Details

File path traversal vulnerabilities arise when user-controllable data is used within a filesystem operation in an unsafe manner. Typically, a user-supplied filename is appended to a directory prefix in order to read or write the contents of a file. If vulnerable, an attacker can supply path traversal sequences (using dot-dot-slash characters) to break out of the intended directory and read or write files elsewhere on the filesystem.

PoC

1. Access the below URL to see the contents of /etc/passwd: URL with payload: https://yeswiki.net/?UrkCEO/edit&theme=margot&squelette=..%2f..%2f..%2f..%2f..%2f..%2fetc%2fpasswd&style=margot.css

   Similarly, contents of wakka.config.php can be read (which contains database password) using ..%2f..%2f..%2fwakka.config.php as payload. Thus showing the severity of this issue.

Impact

This is a very serious vulnerability, allowing an attacker to access sensitive files containing configuration data, passwords, database records, log data, source code, and program scripts and binaries. Thus, leading to complete loss of confidentiality.