CVE-2020-8142 in Adserver
Summary
by MITRE
A security restriction bypass vulnerability has been discovered in Revive Adserver version < 5.0.5 by HackerOne user hoangn144. Revive Adserver, like many other applications, requires the logged in user to type the current password in order to change the e-mail address or the password. It was however possible for anyone with access to a Revive Adserver admin user interface to bypass such check and change e-email address or password of the currently logged in user by altering the form payload.The attack requires physical access to the user interface of a logged in user. If the POST payload was altered by turning the “pwold� parameter into an array, Revive Adserver would fetch and authorise the operation even if no password was provided.
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Analysis
by VulDB Data Team • 05/13/2024
The vulnerability CVE-2020-8142 represents a critical security restriction bypass in Revive Adserver versions prior to 5.0.5, demonstrating a fundamental flaw in authentication and authorization mechanisms. This issue was identified by security researcher hoangn144 through careful analysis of the application's form handling and validation processes. The vulnerability specifically targets the password change functionality, where the system should enforce strict authentication requirements before allowing sensitive modifications to user credentials. The flaw arises from inadequate input validation and improper handling of form data, creating a pathway for unauthorized privilege escalation through session hijacking or session manipulation techniques.
The technical implementation of this vulnerability exploits a common pattern in web application security where parameter validation fails to properly sanitize user input. When an attacker manipulates the form payload by converting the pwold parameter into an array structure, the application's backend processing logic fails to properly validate the input type. This misconfiguration allows the system to accept the modified payload without requiring the legitimate password confirmation, effectively bypassing the intended security control. The vulnerability specifically affects the password change and email address modification functions, which are typically protected by multi-factor authentication requirements that should verify the current password before permitting changes to sensitive account information.
From an operational perspective, this vulnerability creates a significant risk for organizations using Revive Adserver, particularly those managing digital advertising platforms where administrative access can be leveraged for malicious activities. The attack requires only physical access to a logged-in user interface, making it particularly dangerous in shared or unsecured environments where administrators might leave their sessions active. This type of vulnerability falls under CWE-284, which addresses improper access control, and aligns with ATT&CK technique T1078.004 for valid accounts, as it allows attackers to leverage existing administrative sessions to perform unauthorized modifications. The impact extends beyond simple credential theft to include potential data manipulation, service disruption, and unauthorized access to sensitive advertising campaign information.
The mitigation strategy for this vulnerability involves implementing proper input validation and parameter sanitization within the application's form processing logic. Organizations should ensure that all form parameters undergo strict type checking and that array inputs are properly validated against expected data types. The fix requires updating Revive Adserver to version 5.0.5 or later, where the developers have implemented proper parameter validation and authentication flow controls. Security teams should also implement additional monitoring for unusual form submission patterns and consider implementing rate limiting and session management improvements. The vulnerability demonstrates the importance of proper input validation and the principle of least privilege in web application security, where authentication checks must be robust and cannot be bypassed through simple payload manipulation techniques.