CVE-2023-2803 in Ultimate Addons for Contact Form 7 Plugin
Summary
by MITRE • 08/14/2023
The Ultimate Addons for Contact Form 7 WordPress plugin before 3.1.29 does not sanitise and escape a parameter before outputting it back in the page, leading to a Reflected Cross-Site Scripting which could be used against high privilege users such as admin.
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Analysis
by VulDB Data Team • 09/09/2023
The vulnerability identified as CVE-2023-2803 affects the Ultimate Addons for Contact Form 7 WordPress plugin, specifically versions prior to 3.1.29. This issue represents a critical security flaw that arises from improper input validation and output sanitization practices within the plugin's codebase. The vulnerability manifests as a reflected cross-site scripting vulnerability that occurs when user-supplied data is not adequately sanitized before being rendered back to the browser. The flaw exists in the plugin's handling of parameters that are passed through HTTP requests and subsequently displayed without proper escaping mechanisms, creating an avenue for malicious actors to inject arbitrary JavaScript code into web pages viewed by unsuspecting users.
The technical implementation of this vulnerability stems from a failure to apply proper output escaping techniques when processing user input within the plugin's administrative interfaces or contact form rendering components. When a user submits data through a contact form that utilizes this plugin, the submitted parameters may be reflected back to the browser in the page content without appropriate sanitization. This creates a condition where an attacker could craft malicious input containing script tags or other malicious code that would execute in the context of a victim's browser session. The vulnerability is particularly concerning because it targets high-privilege users such as administrators, meaning that successful exploitation could lead to complete compromise of the WordPress installation and potentially the entire web server infrastructure.
The operational impact of this vulnerability extends beyond simple script execution, as it represents a significant risk to WordPress site security and user data integrity. Attackers could leverage this reflected XSS vulnerability to steal administrative credentials, modify content, install malware, or perform other malicious activities that would be difficult to trace back to the original source. The vulnerability's ability to target administrators makes it especially dangerous because it could enable attackers to gain persistent access to sensitive administrative functions, potentially allowing them to modify plugin settings, create new admin users, or even completely take over the WordPress installation. The reflected nature of the vulnerability means that attackers would need to entice administrators to click on malicious links, but once clicked, the attack would be executed in the context of the administrator's session with full privileges.
Mitigation strategies for this vulnerability should prioritize immediate patching of the affected plugin to version 3.1.29 or later, which contains the necessary sanitization and escaping mechanisms. Organizations should also implement additional defensive measures including the implementation of content security policies to limit script execution, regular monitoring of plugin updates and security advisories, and the enforcement of principle of least privilege for WordPress administrative accounts. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and it maps to ATT&CK technique T1566.001 for social engineering through malicious links that could be used to deliver the reflected payload. Security teams should also consider implementing web application firewalls to detect and block suspicious input patterns that could indicate attempts to exploit this vulnerability, while maintaining comprehensive logging and monitoring of administrative activities to detect potential exploitation attempts.