CVE-2018-16979 in Monstra
Summary
by MITRE
Monstra CMS V3.0.4 allows HTTP header injection in the plugins/captcha/crypt/cryptographp.php cfg parameter, a related issue to CVE-2012-2943.
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Analysis
by VulDB Data Team • 03/23/2020
The vulnerability identified as CVE-2018-16979 affects Monstra CMS version 3.0.4 and represents a critical HTTP header injection flaw within the captcha plugin component. This issue manifests in the plugins/captcha/crypt/cryptographp.php file where the cfg parameter fails to properly sanitize user input, creating an avenue for malicious actors to inject arbitrary HTTP headers into the application's response. The vulnerability is particularly concerning as it builds upon the well-documented CVE-2012-2943, which established precedent for similar header injection attacks in web applications, demonstrating the persistence of such flaws in content management systems. The flaw stems from insufficient input validation and sanitization practices within the cryptographic captcha implementation, allowing attackers to manipulate HTTP headers that are subsequently processed by the web server.
The technical exploitation of this vulnerability occurs when user-supplied data from the cfg parameter is directly incorporated into HTTP response headers without proper encoding or validation. This creates opportunities for attackers to inject malicious headers such as Set-Cookie, Location, or other response headers that can redirect users to malicious sites, establish unauthorized session cookies, or manipulate browser behavior. The attack vector typically involves crafting malicious input that bypasses normal input validation mechanisms and gets processed through the cryptographic captcha library. This type of vulnerability falls under CWE-113, which specifically addresses improper neutralization of CRLF characters in HTTP headers, and aligns with ATT&CK technique T1190 for exploiting vulnerabilities in web applications. The weakness exists in the application's failure to implement proper input sanitization and output encoding, creating a direct path for header manipulation that can be leveraged in various attack scenarios.
The operational impact of this vulnerability extends beyond simple header injection, potentially enabling more sophisticated attacks including open redirectors, session hijacking, and cross-site scripting exploitation when combined with other vulnerabilities. Attackers can leverage this flaw to redirect users to phishing sites, inject malicious cookies that persist across sessions, or manipulate application behavior through crafted HTTP headers. The vulnerability affects the integrity of the web application's response handling and can compromise user sessions, especially when combined with other injection flaws that may exist within the same codebase. This type of vulnerability is particularly dangerous in CMS environments where multiple plugins and components interact, as it can serve as a stepping stone for more comprehensive attacks. Organizations using Monstra CMS v3.0.4 are at risk of unauthorized access, data manipulation, and potential complete system compromise if this vulnerability remains unpatched.
Mitigation strategies for CVE-2018-16979 require immediate patching of the affected Monstra CMS version, with developers implementing proper input validation and sanitization for all parameters that influence HTTP response headers. The fix should include implementing strict input filtering to prevent CRLF character injection, employing proper output encoding when headers are constructed, and ensuring that all user-supplied parameters are validated against expected input formats. Organizations should also consider implementing web application firewalls that can detect and block header injection attempts, while conducting thorough security testing to identify similar vulnerabilities in other components of the application. The remediation process should involve comprehensive code review of all plugin components that handle user input, with particular attention to HTTP header manipulation functions. Additionally, implementing proper logging and monitoring for unusual header patterns can help detect exploitation attempts, while adherence to secure coding practices such as those outlined in OWASP Top 10 and NIST cybersecurity guidelines should be maintained throughout the application development lifecycle.