CVE-2015-7364 in Adserver
Summary
by MITRE
The HTML_Quickform library, as used in Revive Adserver before 3.2.2, allows remote attackers to bypass the CSRF protection mechanism via an empty token.
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Analysis
by VulDB Data Team • 06/21/2022
The CVE-2015-7364 vulnerability represents a critical weakness in the HTML_Quickform library implementation within Revive Adserver versions prior to 3.2.2, specifically targeting the Cross-Site Request Forgery protection mechanism. This flaw stems from the library's improper handling of CSRF tokens when they are empty or null, creating a pathway for malicious actors to circumvent security controls designed to prevent unauthorized actions. The vulnerability exists within the core token validation logic where the system fails to properly validate or reject empty tokens, allowing attackers to forge requests that appear legitimate to the application's security mechanisms.
The technical implementation of this vulnerability lies in the CSRF protection mechanism's token validation process within the HTML_Quickform library. When the library processes form submissions, it expects a valid CSRF token to be present and properly validated. However, in affected versions of Revive Adserver, the validation logic does not adequately check for empty or null tokens, permitting attackers to submit forms without proper token authentication. This weakness directly aligns with CWE-352, which categorizes Cross-Site Request Forgery vulnerabilities, and demonstrates how improper input validation can undermine security controls. The flaw essentially creates a bypass condition where empty tokens are treated as valid, undermining the fundamental premise of CSRF protection that requires unique, unpredictable tokens for each user session.
The operational impact of this vulnerability is substantial as it enables remote attackers to perform unauthorized actions within the context of authenticated users. An attacker could craft malicious web pages or exploit existing vulnerabilities to trick users into submitting forms that bypass CSRF protection, potentially leading to account takeovers, unauthorized configuration changes, or data manipulation within the adserver environment. This vulnerability particularly affects web applications that rely on the HTML_Quickform library for form handling and security validation, making it a significant concern for any organization using affected versions of Revive Adserver. The attack surface extends beyond simple form submissions to include any functionality that depends on CSRF protection, potentially compromising the entire administrative interface and user management capabilities.
Mitigation strategies for CVE-2015-7364 focus primarily on updating to Revive Adserver version 3.2.2 or later, which contains the necessary patches to properly validate CSRF tokens and reject empty or null values. Organizations should also implement additional defensive measures including thorough input validation, monitoring for anomalous form submission patterns, and ensuring that all CSRF tokens are properly generated and validated with sufficient entropy. The vulnerability's remediation aligns with ATT&CK technique T1213, which addresses credential access through the exploitation of weak authentication mechanisms, and emphasizes the importance of maintaining up-to-date software components to prevent exploitation of known vulnerabilities. Network segmentation and web application firewalls can provide additional layers of protection while awaiting the official patch deployment, though the most effective solution remains the immediate upgrade to patched versions of the software.