CVE-2004-1230 in Instant Messenger
Summary
by MITRE
Gadu-Gadu allows remote attackers to gain sensitive information and read files from the _cache directory of other users via a DCC connection and a CTCP packet that contains a 1 as the type and a 4 as the subtype.
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Analysis
by VulDB Data Team • 07/21/2017
The Gadu-Gadu instant messaging protocol implementation contains a critical information disclosure vulnerability that enables remote attackers to access sensitive data from other users' systems through malicious DCC connections. This vulnerability resides in the protocol's handling of CTCP (Client-to-Client Protocol) packets during direct client connections, specifically when processing packets with type 1 and subtype 4. The flaw allows unauthorized access to the _cache directory contents of remote user accounts, potentially exposing confidential information stored in cached files.
This security weakness stems from inadequate input validation and privilege separation within the DCC communication mechanism. When a malicious user establishes a DCC connection with a target system, the protocol processes incoming CTCP packets without proper authorization checks or path validation. The specific packet structure with type 1 and subtype 4 triggers a file access operation that bypasses normal permission controls, allowing arbitrary file reading from the target's cache directory. This vulnerability represents a classic case of insufficient access control and improper input sanitization, aligning with CWE-284 for improper access control and CWE-73 for external control of filename or path.
The operational impact of this vulnerability extends beyond simple information disclosure, as the cached directory may contain sensitive user data including temporary files, chat logs, configuration settings, or other potentially confidential information. Attackers can leverage this weakness to gather intelligence about target users, potentially leading to further exploitation attempts or social engineering campaigns. The remote nature of the attack means that an attacker needs only to establish a DCC connection with a victim to exploit this vulnerability, making it particularly dangerous in messaging environments where users frequently accept connection requests from unknown parties. This weakness directly maps to attack techniques described in the MITRE ATT&CK framework under T1083 for discovering system information and T1074 for data staging.
Mitigation strategies should focus on implementing proper access controls and input validation within the DCC connection handling code. System administrators should consider disabling DCC functionality if it is not essential for operations, as this removes the attack surface entirely. Additionally, implementing proper path validation and privilege separation when processing CTCP packets would prevent unauthorized file access attempts. The vulnerability highlights the importance of secure coding practices and proper security testing for communication protocols, particularly those handling user data and file operations. Regular security audits and code reviews should specifically target input validation mechanisms and access control implementations to prevent similar weaknesses from being introduced in future versions of the software.