CVE-2017-6819 in WordPress
Summary
by MITRE
In WordPress before 4.7.3, there is cross-site request forgery (CSRF) in Press This (wp-admin/includes/class-wp-press-this.php), leading to excessive use of server resources. The CSRF can trigger an outbound HTTP request for a large file that is then parsed by Press This.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 12/25/2024
The vulnerability identified as CVE-2017-6819 represents a critical cross-site request forgery weakness within WordPress versions prior to 4.7.3, specifically affecting the Press This functionality located in wp-admin/includes/class-wp-press-this.php. This flaw allows malicious actors to exploit the system's trust relationship with authenticated users, enabling unauthorized actions that can significantly impact server performance and resource utilization. The vulnerability operates through a sophisticated attack vector that leverages the legitimate user session to execute unintended operations without their knowledge or consent.
The technical implementation of this CSRF vulnerability stems from insufficient validation of request origins within the Press This component, which is designed to help users quickly capture and share content from other websites. When a user visits a malicious site containing crafted HTML forms or JavaScript, the system can automatically submit requests to the vulnerable WordPress installation, triggering the Press This functionality to make outbound HTTP requests to external resources. This mechanism becomes particularly dangerous when the target URL points to large files that must be downloaded and processed by the Press This parser, creating a resource exhaustion scenario.
The operational impact of this vulnerability extends beyond simple resource consumption, as it can lead to significant server performance degradation and potential denial of service conditions. Attackers can craft malicious payloads that trigger multiple simultaneous requests to download large files, overwhelming server resources such as memory, CPU cycles, and bandwidth. The Press This functionality's design to parse and process external content makes it particularly susceptible to abuse, as the system must handle the downloaded content through various processing stages including content sanitization, metadata extraction, and format conversion. This processing overhead compounds the resource consumption problem, making the attack exponentially more damaging than a simple file download.
From a cybersecurity perspective, this vulnerability aligns with CWE-352, which specifically addresses cross-site request forgery conditions in web applications. The flaw demonstrates how seemingly benign functionality can become a vector for significant security compromise when proper input validation and origin verification mechanisms are absent. The attack pattern follows typical CSRF methodologies described in the MITRE ATT&CK framework under the T1548.001 technique for abuse of credentials, where attackers leverage legitimate user sessions to execute malicious actions. Organizations should implement comprehensive mitigations including proper nonce validation, origin checking mechanisms, and rate limiting controls to prevent exploitation of this vulnerability.
The remediation approach requires immediate patching of WordPress installations to version 4.7.3 or later, which includes enhanced CSRF protection measures specifically designed to address this vulnerability. Additionally, administrators should implement network-level controls to monitor and restrict outbound HTTP requests from WordPress installations, particularly those originating from administrative interfaces. Security configurations should enforce strict validation of all incoming requests to Press This functionality and implement proper session management practices that prevent unauthorized access to administrative features. Regular security audits should verify that all WordPress components maintain proper CSRF protection mechanisms and that no legacy functionality introduces similar vulnerabilities through inadequate input validation or session management controls.