CVE-2004-1052 in BNC
Summary
by MITRE
Buffer overflow in the getnickuserhost function in BNC 2.8.9, and possibly other versions, allows remote IRC servers to execute arbitrary code via an IRC server response that contains many (1) ! (exclamation) or (2) @ (at sign) characters.
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Analysis
by VulDB Data Team • 06/05/2019
The vulnerability identified as CVE-2004-1052 represents a critical buffer overflow condition within the BNC IRC bouncer software version 2.8.9 and potentially other iterations. This flaw exists in the getnickuserhost function which processes IRC server responses containing user identification information. The buffer overflow occurs when remote IRC servers send malformed responses containing excessive numbers of exclamation or at sign characters that exceed the allocated buffer space. The technical implementation of this vulnerability stems from inadequate input validation and bounds checking within the IRC protocol parsing logic, creating a scenario where malicious actors can manipulate IRC server communications to overwrite adjacent memory locations. This type of vulnerability falls under the CWE-121 category of stack-based buffer overflow, where insufficient bounds checking allows attackers to write beyond allocated memory boundaries.
The operational impact of this vulnerability extends beyond simple code execution capabilities to encompass complete system compromise potential. When exploited, the buffer overflow enables remote attackers to inject and execute arbitrary code on systems running vulnerable BNC instances, potentially leading to full system control, data exfiltration, or service disruption. The attack vector specifically targets IRC server responses where the getnickuserhost function processes nicknames, usernames, and hostnames in the format user@host or user!host. The vulnerability is particularly dangerous because it leverages legitimate IRC protocol communication channels, making detection more challenging and allowing attackers to operate under the guise of normal network traffic. According to ATT&CK framework, this represents a technique categorized under T1059.007 for command and script interpreter execution, with potential lateral movement capabilities through compromised IRC infrastructure.
Mitigation strategies for CVE-2004-1052 should prioritize immediate software updates to patched versions of BNC software, as the vulnerability affects multiple versions and requires upstream fixes. System administrators must implement network-level filtering to limit excessive character counts in IRC protocol communications, particularly focusing on exclamation and at sign character frequency. The implementation of proper input sanitization and bounds checking within the getnickuserhost function becomes essential, requiring developers to validate string lengths before processing IRC user identification data. Additional protective measures include deploying intrusion detection systems that monitor for unusual IRC protocol patterns, implementing network segmentation to isolate IRC bouncer services, and establishing regular security audits of IRC infrastructure components. Organizations should also consider implementing application whitelisting policies to restrict execution of unauthorized code and maintain comprehensive logging of IRC server communications for forensic analysis. The vulnerability demonstrates the importance of input validation in network protocols and highlights the need for robust memory management practices in long-running network services, particularly those handling user-generated content in IRC environments.