CVE-2005-3537 in phpBB
Summary
by MITRE
A "missing request validation" error in phpBB 2 before 2.0.18 allows remote attackers to edit private messages of other users, probably by modifying certain parameters or other inputs.
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Analysis
by VulDB Data Team • 07/12/2019
The vulnerability identified as CVE-2005-3537 represents a critical security flaw in phpBB version 2.0.17 and earlier, where the application failed to properly validate incoming HTTP requests. This missing request validation mechanism created a significant authorization bypass opportunity that allowed remote attackers to manipulate the application's behavior through crafted input parameters. The flaw specifically affected the private messaging functionality within the phpBB forum system, which is a core component used for secure communication between users.
This vulnerability stems from a fundamental lack of input sanitization and validation within the application's request handling process. The missing validation occurs at the application layer where user-supplied data is processed without proper authorization checks or parameter validation. Attackers could exploit this by crafting malicious HTTP requests that modify parameters associated with private message operations, effectively allowing them to access and manipulate private communications belonging to other users. The vulnerability is classified under CWE-20 as "Improper Input Validation," which specifically addresses the failure to validate or sanitize user-provided data before processing it within the application.
The operational impact of this vulnerability is substantial as it directly compromises the confidentiality and integrity of private communications within the phpBB platform. An attacker could not only read private messages intended for other users but also potentially modify or delete them, leading to unauthorized access to sensitive information and potential disruption of communication channels. This type of vulnerability represents a serious breach of the principle of least privilege, where users can access resources beyond their authorized scope. The attack vector is particularly dangerous because it requires no local access or authentication, making it a remote exploit that can be leveraged from anywhere on the internet.
The security implications extend beyond simple message access, as this vulnerability could be exploited to conduct more sophisticated attacks such as message tampering, unauthorized message creation, or even social engineering campaigns using stolen private communications. From an attacker's perspective, this vulnerability aligns with ATT&CK technique T1566.001 for "Phishing with Social Engineering" and T1078.004 for "Valid Accounts: Cloud Accounts" when considering the broader attack chain that could result from compromising user communications. The flaw demonstrates a critical failure in the application's security architecture where proper access controls were not implemented to verify user authorization before processing private message operations.
Organizations using affected phpBB versions should immediately implement the security patch released with phpBB 2.0.18, which addresses the missing request validation by implementing proper input sanitization and authorization checks. Additionally, administrators should conduct thorough security reviews of all user-facing parameters and implement comprehensive logging of private message operations to detect potential exploitation attempts. The mitigation strategy should include input validation at multiple layers, proper session management, and regular security assessments to identify similar validation gaps in other application components. This vulnerability serves as a critical reminder of the importance of implementing robust input validation and authorization mechanisms at every level of web application development, particularly for sensitive functionality like private messaging systems.