CVE-2016-9129 in Adserver
Summary
by MITRE
Revive Adserver before 3.2.3 suffers from Information Exposure Through Discrepancy. It is possible to check whether or not an email address was associated to one or more user accounts on a target Revive Adserver instance by examining the message printed by the password recovery system. Such information cannot however be used directly to log in to the system, which requires a username.
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Analysis
by VulDB Data Team • 11/22/2022
The vulnerability identified as CVE-2016-9129 represents a significant information disclosure issue within Revive Adserver versions prior to 3.2.3. This flaw resides in the password recovery mechanism of the advertising platform, which is widely used for digital advertising management and campaign tracking. The vulnerability stems from the inconsistent error messaging behavior when users attempt password recovery for email addresses that may or may not be registered within the system. This information exposure through discrepancy creates a potential reconnaissance vector for attackers seeking to identify valid user accounts within the target environment.
The technical implementation of this vulnerability occurs within the password recovery subsystem where the application provides different response messages depending on whether an email address exists in the user database. When a user enters an email address that is not associated with any account, the system returns one type of message indicating that the recovery email has been sent. However, when the email address corresponds to an existing user account, the system returns a different message that confirms the account exists but still requires a username for login access. This differential response behavior creates a timing attack surface that allows attackers to perform account enumeration by systematically testing email addresses and observing the varying system responses.
From an operational impact perspective, this vulnerability enables attackers to conduct user account reconnaissance without requiring authentication or prior access to the system. The ability to determine which email addresses are registered in the Revive Adserver instance provides attackers with valuable intelligence for subsequent attack phases. While the vulnerability does not directly enable account takeover or unauthorized access to user sessions, it significantly weakens the overall security posture by allowing attackers to build a comprehensive list of valid user accounts. This information can then be leveraged for targeted phishing campaigns, credential stuffing attacks against other systems, or as part of broader reconnaissance efforts within a multi-stage attack strategy.
The vulnerability aligns with CWE-200, which addresses information exposure through improper error handling, and can be categorized under ATT&CK technique T1589.001 for credential access through reconnaissance. Organizations using Revive Adserver should implement immediate mitigations including standardizing error messages regardless of account existence, implementing rate limiting on password recovery requests, and ensuring consistent response behavior for all user account queries. The most effective remediation involves updating to Revive Adserver version 3.2.3 or later, where the password recovery mechanism has been patched to provide uniform responses for all account queries, eliminating the information disclosure through discrepancy. Additionally, organizations should consider implementing additional security controls such as account lockout mechanisms and monitoring for unusual password recovery activity patterns to further protect against potential exploitation of this vulnerability.