CVE-2002-2346 in phpBB
Summary
by MITRE
phpBB 2.0 through 2.0.3 generates names for uploaded avatar files with the hex-encoded IP address of the client system, which allows remote attackers to obtain client IP addresses.
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Analysis
by VulDB Data Team • 08/28/2025
The vulnerability described in CVE-2002-2346 represents a significant privacy and security concern within the phpBB forum software ecosystem. This flaw affects versions 2.0 through 2.0.3 of the popular open-source bulletin board system, where the application's avatar upload functionality inadvertently exposes sensitive client information through its file naming mechanism. The vulnerability stems from the application's design decision to incorporate the client's IP address into the generated filename for uploaded avatar images, with the IP address being encoded in hexadecimal format.
The technical implementation of this vulnerability involves phpBB's avatar handling code generating unique filenames for uploaded images by incorporating the remote client's IP address directly into the filename structure. When a user uploads an avatar, the system creates a file name that includes the hex-encoded IP address of the requesting client, effectively creating a direct mapping between the uploaded file and the user's network address. This design flaw occurs in the file naming logic where the application does not properly sanitize or anonymize the client identifier before incorporating it into the filename.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables remote attackers to systematically collect and correlate client IP addresses through the avatar upload process. An attacker can repeatedly upload avatars to different phpBB installations and collect the hex-encoded IP addresses embedded in the generated filenames, thereby building a comprehensive database of user IP addresses. This information can be used for various malicious purposes including targeted attacks, social engineering operations, or network reconnaissance activities. The vulnerability particularly affects systems where users might be behind NAT or firewall configurations, as the IP address exposure provides attackers with direct access to the underlying client network information.
From a cybersecurity perspective, this vulnerability aligns with CWE-200, which addresses improper exposure of sensitive information, and represents a classic case of information leakage through application design flaws. The vulnerability also intersects with ATT&CK technique T1592, which involves reconnaissance activities focused on identifying network infrastructure information. The flaw demonstrates poor input validation and output encoding practices, where the application fails to properly separate user-provided data from system-generated identifiers. Security researchers have noted that this type of vulnerability is particularly dangerous because it operates silently in the background without requiring special privileges or complex attack vectors, making it an attractive target for automated reconnaissance tools.
The recommended mitigation strategies for this vulnerability include immediate upgrading to phpBB version 2.0.4 or later, which contains the necessary patches to address the IP address exposure issue. Administrators should also implement proper access controls and monitoring around avatar upload functionality, ensuring that file naming mechanisms do not inadvertently expose sensitive information. Additionally, organizations should consider implementing network-level protections such as firewalls and intrusion detection systems that can monitor for unusual avatar upload patterns or IP address correlation activities. The vulnerability underscores the importance of proper data sanitization and the principle of least privilege in application design, where system-generated identifiers should never directly incorporate sensitive user information without appropriate anonymization or obfuscation techniques.