CVE-2021-25080 in Contact Form Entries Plugin
Summary
by MITRE • 01/24/2022
The Contact Form Entries WordPress plugin before 1.1.7 does not validate, sanitise and escape the IP address retrieved via headers such as CLIENT-IP and X-FORWARDED-FOR, allowing unauthenticated attackers to perform Cross-Site Scripting attacks against logged in admins viewing the created entry
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Analysis
by VulDB Data Team • 01/28/2022
The vulnerability identified as CVE-2021-25080 affects the Contact Form Entries WordPress plugin version 1.1.6 and earlier, representing a critical security flaw that undermines the integrity of user data handling within WordPress environments. This issue stems from insufficient input validation and sanitization practices within the plugin's codebase, specifically when processing IP address information retrieved from HTTP headers. The affected plugin fails to properly validate, sanitize, and escape IP addresses obtained from headers including CLIENT-IP and X-FORWARDED-FOR, creating an avenue for malicious actors to inject malicious scripts into the system. The vulnerability exists at the intersection of improper input handling and inadequate output escaping, which directly aligns with CWE-79 - Cross-Site Scripting and CWE-20 - Improper Input Validation. Attackers can exploit this weakness by crafting malicious IP addresses or manipulating HTTP headers to inject XSS payloads that will execute when administrators view contact form entries in the WordPress admin interface.
The operational impact of this vulnerability extends beyond simple data corruption, as it enables unauthorized attackers to execute arbitrary JavaScript code within the context of an administrator's browser session. When logged-in administrators access the contact form entries page, the maliciously injected scripts execute in their browser, potentially allowing attackers to hijack sessions, steal credentials, or perform actions with administrative privileges. This creates a significant risk for WordPress installations where the plugin is used to manage contact form submissions, as it transforms the typically benign act of viewing form entries into a potential attack vector. The vulnerability particularly affects environments where multiple users access the WordPress admin interface, as any administrator who views the compromised entries becomes a potential victim of the XSS attack. The attack requires no authentication from the attacker, making it particularly dangerous as it can be exploited by anyone with access to the affected WordPress site.
The technical exploitation of this vulnerability follows established XSS attack patterns, where attackers manipulate HTTP headers to inject malicious payloads that are subsequently rendered in the admin interface without proper sanitization. The plugin's failure to implement proper input validation means that any IP address information, regardless of its source or format, is directly incorporated into the HTML output without appropriate escaping mechanisms. This vulnerability can be classified under the ATT&CK framework as T1059.007 - Command and Scripting Interpreter: JavaScript, where attackers leverage JavaScript injection to execute malicious code. The lack of proper sanitization creates a persistent XSS vulnerability that remains active until the plugin is updated to version 1.1.7 or later, which includes the necessary fixes for input validation and output escaping. Security professionals should note that this vulnerability demonstrates the critical importance of implementing proper input validation and output sanitization practices, particularly when handling data from untrusted sources like HTTP headers that can be easily manipulated by attackers.
Mitigation strategies for this vulnerability involve immediate updating of the Contact Form Entries plugin to version 1.1.7 or later, which contains the necessary patches to address the XSS vulnerability. Organizations should also implement additional security measures such as Content Security Policy (CSP) headers to limit the execution of inline scripts and reduce the impact of potential XSS attacks. Network-level monitoring should be enhanced to detect suspicious header manipulation patterns, and administrators should regularly audit their WordPress installations for outdated plugins that may present similar vulnerabilities. The fix implemented in version 1.1.7 typically includes proper input validation of IP addresses, sanitization of header data, and appropriate output escaping before rendering IP addresses in the admin interface. This vulnerability underscores the importance of regular security updates and the implementation of robust input validation mechanisms as fundamental security practices in web application development, particularly in content management systems where user-generated content and administrative interfaces intersect.