Source: cve@mitre.org
Directory traversal vulnerability in download.php in the DB Backup plugin 4.5 and earlier for Wordpress allows remote attackers to read arbitrary files via a .. (dot dot) in the file parameter.
Critical vulnerability exists in the DB Backup plugin for WordPress, allowing attackers to read arbitrary files on the server. This directory traversal flaw enables unauthorized access to sensitive data, potentially leading to complete system compromise and data breaches. Immediate patching and security audits are essential to mitigate the risk.
Step 1: Vulnerability Discovery: The attacker identifies the presence of the vulnerable DB Backup plugin (version 4.5 or earlier) on a WordPress website.
Step 2: Payload Crafting: The attacker constructs a malicious URL that includes the download.php script and a crafted file parameter. This parameter contains a sequence of ../ (dot-dot-slash) characters to traverse the directory structure. The attacker targets a known sensitive file, such as /wp-config.php or other configuration files.
Step 3: Payload Delivery: The attacker sends the crafted URL to the vulnerable WordPress website. This is typically done through a web browser or a command-line tool like curl.
Step 4: Request Processing: The download.php script receives the request and attempts to download the file specified in the file parameter.
Step 5: File Access: Due to the lack of input validation, the script constructs a file path based on the attacker-controlled file parameter. The ../ sequences in the parameter allow the attacker to navigate to the desired file, bypassing the intended directory restrictions.
Step 6: Data Exfiltration: The script reads the contents of the targeted file (e.g., /wp-config.php) and sends it back to the attacker as the response. The attacker now has access to the sensitive information contained in the file.
The vulnerability stems from insufficient input validation in the download.php script of the DB Backup plugin. Specifically, the script fails to properly sanitize the file parameter, which is used to specify the file to be downloaded. By crafting a malicious URL containing a sequence of ../ (dot-dot-slash) characters, an attacker can traverse the directory structure and access files outside of the intended backup directory. The absence of proper path normalization and input validation allows the attacker to bypass security controls and read sensitive files, such as configuration files containing database credentials or other sensitive information. The root cause is a lack of input validation and path traversal protection within the download.php script. The script directly uses the user-supplied file parameter to construct a file path without verifying its validity or sanitizing it. This allows an attacker to manipulate the file path and access arbitrary files on the server.
While no specific APTs are definitively linked to this specific CVE, the ease of exploitation and potential for data exfiltration make it a target for various threat actors. The impact of this vulnerability is high, and it could be leveraged by attackers for initial access or privilege escalation. This vulnerability is not listed on the CISA KEV at this time, but the nature of the vulnerability makes it a high priority for remediation.
Web server access logs: Look for suspicious requests to download.php with unusual file parameters containing ../ sequences.
File integrity monitoring: Monitor critical files (e.g., /wp-config.php) for unauthorized modifications.
Network traffic analysis: Examine HTTP traffic for requests containing the download.php script and suspicious file parameter values.
Intrusion Detection Systems (IDS): Implement rules to detect directory traversal attempts in HTTP requests.
Security Information and Event Management (SIEM): Correlate web server logs, file integrity monitoring alerts, and network traffic data to identify potential exploitation attempts.
Update the DB Backup plugin to version 4.6 or later. This is the primary and most effective remediation step.
Implement a Web Application Firewall (WAF) with rules to block directory traversal attempts.
Review and harden the web server configuration to prevent access to sensitive files.
Regularly back up the WordPress website and database.
Perform regular security audits and penetration testing to identify and address vulnerabilities.
Implement file access controls to restrict access to sensitive files.