Overview
This article provides an in-depth analysis of CVE-2025-66115, a critical Local File Inclusion (LFI) vulnerability identified in the Easy Invoice WordPress plugin. This vulnerability allows attackers to potentially read sensitive files on the server by manipulating the filename used in PHP’s include/require statements. The affected versions of Easy Invoice are versions 2.1.4 and earlier.
Technical Details
CVE-2025-66115 stems from an “Improper Control of Filename for Include/Require Statement” vulnerability. This means the Easy Invoice plugin doesn’t adequately sanitize or validate user-supplied input that is then used as part of a file path in a PHP `include`, `require`, `include_once`, or `require_once` statement. An attacker can exploit this weakness by crafting a malicious request that includes directory traversal sequences (e.g., `../../`) to navigate outside the intended directory and access arbitrary files on the server.
For example, a vulnerable parameter could be exploited like this:
https://example.com/wp-content/plugins/easy-invoice/vulnerable_script.php?file=../../../../wp-config.phpThis malicious request could potentially expose sensitive information stored in the `wp-config.php` file, such as database credentials.
CVSS Analysis
Currently, the CVSS score for CVE-2025-66115 is marked as N/A. While a score isn’t yet assigned, the nature of a Local File Inclusion vulnerability often leads to a high severity rating due to the potential for sensitive data exposure and further exploitation. It is crucial to understand that even without a formally assigned CVSS score, the risk associated with LFI is significant.
Possible Impact
Successful exploitation of CVE-2025-66115 can have severe consequences:
- Sensitive Data Exposure: Attackers can read configuration files (like `wp-config.php`), potentially revealing database credentials, API keys, and other sensitive information.
- Code Execution (Potentially): In certain server configurations, an attacker might be able to include log files or other files containing PHP code, leading to remote code execution (RCE). This is less common but possible.
- Information Gathering: Attackers can gather information about the server’s file structure and configuration, aiding in further attacks.
Mitigation and Patch Steps
To mitigate the risk posed by CVE-2025-66115, follow these steps:
- Update the Plugin: Immediately update the Easy Invoice plugin to the latest version. Check the WordPress plugin repository or the plugin developer’s website for updates. If a patched version is available, install it as soon as possible.
- Disable the Plugin: If an update is not immediately available, temporarily disable the Easy Invoice plugin until a patched version is released.
- Web Application Firewall (WAF): Implement a Web Application Firewall (WAF) with rules to detect and block LFI attacks. Configure the WAF to filter out suspicious requests containing directory traversal sequences.
- Input Validation: If you are a developer of the Easy Invoice plugin (or contributing to it), implement robust input validation and sanitization techniques to prevent directory traversal. Never trust user-supplied input directly in file inclusion statements. Use whitelisting to allow only specific file paths.
