CVE-2010-2934 in ZNC
Summary
by MITRE
Multiple unspecified vulnerabilities in ZNC 0.092 allow remote attackers to cause a denial of service (exception and daemon crash) via unknown vectors related to "unsafe substr() calls."
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Analysis
by VulDB Data Team • 09/23/2021
The vulnerability identified as CVE-2010-2934 affects ZNC version 0.092, a popular open source Internet Relay Chat (IRC) bouncer software that allows users to maintain persistent connections to IRC networks while being offline. This issue represents a critical security flaw that can be exploited by remote attackers to disrupt service availability through carefully crafted input sequences. The vulnerability specifically relates to unsafe string manipulation operations within the software's codebase, particularly concerning the substr() function calls that are fundamental to text processing in the application. These unsafe operations create conditions where malformed input can trigger unexpected behavior in the program's execution flow.
The technical flaw stems from improper handling of string substrings in the ZNC daemon implementation, where the software fails to validate input boundaries before performing substring operations. This type of vulnerability falls under the category of buffer overflows and memory corruption issues, which are commonly classified as CWE-129, indicating weakness in the validation of the length of input. When attackers exploit this vulnerability, they can cause the ZNC daemon to crash and restart, effectively creating a denial of service condition that prevents legitimate users from accessing IRC services through the bouncer. The attack vector is particularly dangerous because it requires no authentication and can be executed from any remote location, making it a significant threat to systems running vulnerable versions of ZNC.
The operational impact of this vulnerability extends beyond simple service disruption, as it can compromise the reliability and availability of IRC communications for users who depend on the ZNC bouncer for maintaining persistent connections. Organizations and individuals relying on ZNC for IRC connectivity face potential exposure to continuous service interruptions that can last from minutes to hours depending on the system recovery mechanisms in place. The vulnerability's exploitation can occur through various means including malformed IRC messages, specially crafted channel names, or other input fields where substring operations are performed. According to ATT&CK framework categorization, this vulnerability aligns with T1499.004, which covers network disruption through service availability attacks, and represents a form of resource exhaustion that affects system availability.
Mitigation strategies for CVE-2010-2934 require immediate attention from system administrators and security teams responsible for maintaining ZNC installations. The most effective immediate solution involves upgrading to a patched version of ZNC that addresses the unsafe substr() calls and implements proper input validation mechanisms. Organizations should also consider implementing network-level protections such as firewall rules that limit access to IRC ports and monitor for suspicious traffic patterns that might indicate exploitation attempts. Additionally, deploying intrusion detection systems that can identify anomalous behavior patterns associated with buffer overflow attempts can provide early warning capabilities. The vulnerability demonstrates the importance of proper input validation and boundary checking in software development, particularly in applications that process untrusted data from network sources. System administrators should also implement regular security audits of their IRC infrastructure and maintain updated threat intelligence to identify potential exploitation attempts against known vulnerabilities in their network services.