Description
A critical vulnerability, identified as CVE-2024-13725, has been found in the Keap Official Opt-in Forms plugin for WordPress. This vulnerability involves a Local File Inclusion (LFI) flaw, which allows unauthenticated attackers to include PHP files stored on the server. Exploitation of this vulnerability could lead to bypassing access controls, leaking sensitive data, or even executing arbitrary PHP code on the server. This issue can further escalate to Remote Code Execution (RCE) on systems where specific configurations such as `register_argc_argv` are enabled and pearcmd.php is present.
Affected Product(s)
Keap Official Opt-in Forms Plugin for WordPress โ Versions up to and including 2.0.1
Technical Details
This vulnerability arises due to improper input validation and sanitization in the Keap Official Opt-in Forms plugin for WordPress. Specifically, the `service` parameter used within the plugin fails to adequately validate user input, allowing attackers to inject file paths that are subsequently included and processed by the server. This kind of vulnerability is referred to as Local File Inclusion (LFI). LFI occurs when a web application allows the inclusion of files located on its own file system without proper validation.
In the case of this plugin, attackers can manipulate user input to include arbitrary PHP files from the server. These files, if crafted appropriately, can execute malicious PHP code. Examples of potential impacts include unauthorized data disclosure, access control bypass, or, in more severe instances, full control of the server via Remote Code Execution (RCE).
What makes this vulnerability particularly alarming is its ability to escalate under certain server configurations. For instance, if the `register_argc_argv` PHP directive is enabled (a common scenario in many shared hosting environments) and the file `pearcmd.php` is installed on the server, attackers can launch more advanced attacks. `Pearcmd.php` is a command-line PHP module often associated with the PEAR (PHP Extension and Application Repository) library. Attackers can exploit this to execute arbitrary commands on the underlying system, thereby achieving RCE. The practical implications of this vulnerability include:
- **Exploitation vector**: An unauthenticated user only needs to send a specially crafted request with a tampered `service` parameter.
- **Tools required**: A simple web request using curl, Burp Suite, or other HTTP clients is sufficient to exploit this LFI vulnerability.
- **Wider attack scope**: Successful exploitation grants attackers extensive control over the compromised server. They can exfiltrate sensitive data like database credentials, customer PII (Personally Identifiable Information), and more. Advanced attackers can establish backdoors for persistent access.
- **Environmental prerequisites**: While LFI itself can lead to severe consequences, the vulnerability becomes even more dangerous when specific configurations exist, such as the presence of `register_argc_argv` and the inclusion of specific PHP modules like pearcmd.php.
Given the popularity of WordPress as a CMS (Content Management System), this plugin’s widespread usage increases the attack surface significantly. Threat intelligence notes have reported similar vulnerabilities being actively exploited by attackers across high-profile plugins, making timely remediation critical for all affected users.
For reference purposes, the vulnerability is linked to the Common Weakness Enumeration (CWE) category **CWE-22**, which addresses weaknesses related to “Improper Limitation of a Pathname to a Restricted Directory” or classic “Path Traversal” attacks. This underscores the role of sanitized path validation mechanisms in averting such risks. Ongoing research and threat actor activity in this domain highlight the need for maintaining strict input sanitization practices in all web-based applications.
Weakness
The vulnerability is categorized under CWE-22: “Improper Limitation of a Pathname to a Restricted Directory (‘Path Traversal’).” This weakness signifies that the application does not properly restrict file paths provided by users, enabling unauthorized inclusion and execution of sensitive files.
Impact Assessment
If exploited, this vulnerability could result in severe consequences:
- **Unauthorized Access**: The inclusion of unintended files could bypass authentication mechanisms or access controls.
- **Sensitive Data Exposure**: Attackers might gain access to sensitive or system-critical data, such as configuration files containing database credentials and API keys.
- **Arbitrary Code Execution**: By including malicious PHP files, attackers can execute arbitrary code on the affected server, potentially leading to complete server compromise.
- **Remote Code Execution (RCE)**: On servers where specific prerequisites are met, such as `register_argc_argv` being enabled and pearcmd.php being present, the vulnerability can escalate to RCE, allowing attackers to execute commands on the server as though they were a legitimate system administrator.
Active Exploitation
At the time of writing, no specific threat actor groups have been identified exploiting this vulnerability. However, given the CVSS score of 9.8 and the critical nature of this vulnerability, widespread exploitation may occur shortly. Attackers are often quick to leverage such vulnerabilities in unpatched WordPress plugins, taking advantage of automated tools and scripts to scan and exploit vulnerable installations.
Ransomware Association
This vulnerability holds significant potential for association with ransomware campaigns. Typically, attackers may use the Local File Inclusion to achieve initial access and establish persistence. Once inside the system, ransomware payloads can be deployed to encrypt critical files or demand ransom from affected organizations. The ease of exploitation coupled with the high attack surface makes it an attractive entry point for ransomware operators.
Mitigation and Resolution
Keap has yet to release an official security patch to address this vulnerability. Administrators are encouraged to disable the affected plugin immediately or restrict access to WordPress installations using server-level rules such as web application firewalls (WAFs) until a fix is available. Ensuring proper server-level configurations, such as disabling `register_argc_argv` and removing unused modules like pearcmd.php, can minimize the risk of exploitation.
Recommendations
- Immediately deactivate the Keap Official Opt-in Forms plugin on WordPress.
- Remove the plugin from your WordPress installation if not actively required.
- Regularly review and apply updates or patches for installed plugins.
- Configure a Web Application Firewall (WAF) to block malicious requests targeting vulnerabilities like LFI.
- Disable `register_argc_argv` in the PHP configuration to mitigate risk from advanced chains leading to RCE.
- Audit server configurations to ensure that unused modules like pearcmd.php are not installed.
- Monitor server logs for anomalous or suspicious requests targeting the `service` parameter.
- Apply the principle of least privilege to reduce the scope of damage if exploitation occurs.
- Backup critical data regularly and ensure backups are stored on an isolated system.
Referencesย
- CVE MITRE Details
- NVD Database
- WordPress Plugin Details 1
- WordPress Plugin Details 2
- WordFence Threat Intel