CVE-2002-1820 in Ultimate Php Board
Summary
by MITRE
register.php in Ultimate PHP Board (UPB) 1.0 and 1.0b uses an administrative account Admin with a capital "A," but allows a remote attacker to impersonate the administrator by registering an account name of admin with a lower case "a."
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 04/19/2019
This vulnerability exists in the Ultimate PHP Board version 1.0 and 1.0b web application where the administrative account is configured with a capital "A" in the username "Admin" while the system permits any user to register an account with the lowercase variant "admin". The flaw stems from a case-insensitive username registration mechanism that fails to properly validate or prevent duplicate account creation when the username differs only by case sensitivity. This represents a classic authentication bypass vulnerability that violates security principles of account uniqueness and access control enforcement. The vulnerability directly relates to CWE-611 Insufficient Verification of Data Authenticity and CWE-287 Improper Authentication, as the system does not properly verify that the requested username is not already in use regardless of case variations. From an operational perspective, this vulnerability allows remote attackers to gain administrative privileges by simply registering a lowercase username that conflicts with the existing administrative account, effectively creating a backdoor access point. The attacker can then perform any administrative actions including modifying user permissions, deleting content, accessing sensitive data, or compromising the entire forum infrastructure. This type of vulnerability is particularly concerning in web applications where administrative access can be leveraged to establish persistent access or conduct further attacks on the underlying network. The attack vector is straightforward and requires minimal technical skill, making it a high-risk vulnerability that aligns with ATT&CK technique T1078 Valid Accounts, specifically targeting credential reuse and account takeover scenarios. The vulnerability demonstrates poor input validation and account management practices that violate fundamental security design principles. Organizations using this software are exposed to immediate privilege escalation risks, as the registration process does not enforce unique username constraints across case variations. The impact extends beyond simple unauthorized access to include potential data breaches, service disruption, and compromise of the entire application environment. This vulnerability also highlights the importance of implementing proper account validation mechanisms that consider case sensitivity during registration processes and maintain strict uniqueness constraints for administrative accounts. The flaw represents a failure in the application's authentication and authorization framework, where the system should have enforced username uniqueness regardless of case differences. Mitigation efforts should include immediate patching of the software, implementation of case-sensitive username validation, and enforcement of unique account naming policies. Additionally, the system should be configured to prevent registration of usernames that conflict with existing administrative accounts, regardless of case variations, to prevent similar vulnerabilities from being exploited in the future. This type of vulnerability is particularly dangerous in environments where administrative access can be leveraged to gain deeper system access or to maintain persistent presence within the network infrastructure.