CVE-2020-35948 in XCloner Backup and Restore Plugin
Summary
by MITRE • 01/01/2021
An issue was discovered in the XCloner Backup and Restore plugin before 4.2.13 for WordPress. It gave authenticated attackers the ability to modify arbitrary files, including PHP files. Doing so would allow an attacker to achieve remote code execution. The xcloner_restore.php write_file_action could overwrite wp-config.php, for example. Alternatively, an attacker could create an exploit chain to obtain a database dump.
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Analysis
by VulDB Data Team • 03/11/2025
The vulnerability in the XCloner Backup and Restore plugin affects versions prior to 4.2.13 and represents a critical privilege escalation flaw that enables authenticated attackers to manipulate arbitrary files on affected WordPress installations. This issue stems from insufficient input validation and access control mechanisms within the plugin's file manipulation functions, specifically the write_file_action functionality in xcloner_restore.php. The flaw allows authenticated users to perform unauthorized file operations that can result in complete system compromise through remote code execution capabilities.
The technical implementation of this vulnerability resides in the plugin's restore functionality where the write_file_action method fails to properly validate file paths and user permissions. Attackers can leverage this weakness to overwrite critical system files including wp-config.php which contains database credentials and security keys, or to inject malicious code into PHP files that will execute when the web server processes them. This represents a classic path traversal and file overwrite vulnerability that aligns with CWE-22 Path Traversal and CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component. The vulnerability operates under the principle that authenticated users should not be able to write to arbitrary locations on the filesystem, which violates fundamental security principles of least privilege and access control.
The operational impact of this vulnerability extends beyond simple file modification to encompass complete system compromise and data exfiltration capabilities. When an attacker successfully overwrites wp-config.php, they can gain access to database credentials and potentially escalate privileges to full system control. Additionally, the vulnerability enables attackers to create exploit chains that can lead to database dumps, allowing for further reconnaissance and data theft. This type of vulnerability can be classified under the MITRE ATT&CK framework as T1078 Valid Accounts for initial access and T1059 Command and Scripting Interpreter for execution, with potential lateral movement through database access. The attack surface is particularly concerning because WordPress installations often run with elevated privileges and the plugin's restore functionality is typically accessible to users with administrative or editor roles.
Mitigation strategies should focus on immediate plugin updates to version 4.2.13 or later where the vulnerability has been patched. Organizations should also implement network segmentation and monitoring to detect unauthorized file modifications, particularly in web root directories. Access control measures including role-based permissions should be reviewed to ensure that only trusted administrators have access to backup and restore functionalities. Additionally, implementing file integrity monitoring solutions and regular security audits of WordPress plugins can help identify similar vulnerabilities before they can be exploited. The remediation process should include verifying that all backup files are properly sanitized and that file operations are validated against a whitelist of acceptable paths to prevent path traversal attacks. Organizations should also consider implementing web application firewalls to monitor and block suspicious file manipulation requests.