CVE-2016-7143 in Charybdis
Summary
by MITRE
The m_authenticate function in modules/m_sasl.c in Charybdis before 3.5.3 allows remote attackers to spoof certificate fingerprints and consequently log in as another user via a crafted AUTHENTICATE parameter.
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Analysis
by VulDB Data Team • 09/23/2024
The vulnerability identified as CVE-2016-7143 resides within the Charybdis IRC server software, specifically in the m_sasl.c module's m_authenticate function. This flaw represents a critical authentication bypass vulnerability that undermines the security of the server's certificate-based authentication system. The issue affects versions prior to 3.5.3, making it a significant concern for organizations running older installations of this widely-used IRC server software.
The technical flaw stems from insufficient validation of certificate fingerprints during the SASL authentication process. When a client attempts to authenticate using certificate-based methods, the m_authenticate function fails to properly verify the authenticity of the certificate presented. Attackers can exploit this weakness by crafting a malicious AUTHENTICATE parameter that contains a forged certificate fingerprint, enabling them to impersonate legitimate users within the IRC network. This vulnerability directly violates the principle of authentication integrity, as defined by CWE-287, which addresses improper authentication mechanisms.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to assume the identity of legitimate users within the IRC environment. This can lead to severe consequences including unauthorized channel access, message spoofing, privilege escalation, and potential network disruption. The ability to spoof certificate fingerprints means that attackers can bypass the certificate-based authentication layer entirely, rendering the security measures ineffective. This type of attack aligns with ATT&CK technique T1566, specifically focusing on credential access through the exploitation of authentication mechanisms.
Organizations affected by this vulnerability should prioritize immediate patching of their Charybdis installations to version 3.5.3 or later, where the authentication validation has been properly strengthened. Additionally, network administrators should implement monitoring for suspicious authentication patterns and consider implementing additional security layers such as IP-based restrictions or more robust certificate validation mechanisms. The vulnerability demonstrates the critical importance of proper input validation in authentication systems, as highlighted by CWE-287's emphasis on ensuring that authentication mechanisms properly verify credentials. This weakness serves as a reminder that even minor flaws in authentication code can have significant security implications, particularly in environments where user identity verification is paramount for network integrity and access control.