CVE-2022-28352 in WeeChat
Summary
by MITRE • 04/02/2022
WeeChat (aka Wee Enhanced Environment for Chat) 3.2 to 3.4 before 3.4.1 does not properly verify the TLS certificate of the server, after certain GnuTLS options are changed, which allows man-in-the-middle attackers to spoof a TLS chat server via an arbitrary certificate. NOTE: this only affects situations where weechat.network.gnutls_ca_system or weechat.network.gnutls_ca_user is changed without a WeeChat restart.
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Analysis
by VulDB Data Team • 04/05/2022
CVE-2022-28352 represents a critical security vulnerability in WeeChat versions 3.2 through 3.4 before 3.4.1 that undermines the integrity of TLS certificate verification mechanisms. This vulnerability specifically targets the GnuTLS implementation within WeeChat's network security framework and operates through a subtle but dangerous flaw in the certificate validation process. The issue manifests when users modify the weechat.network.gnutls_ca_system or weechat.network.gnutls_ca_user configuration options without restarting the WeeChat application, creating a window where TLS certificate verification becomes compromised. This represents a classic case of configuration drift vulnerability where runtime modifications to security parameters do not properly invalidate existing TLS connections or revalidate certificate chains, leaving the application in a state where it may accept arbitrary certificates from malicious actors.
The technical flaw stems from improper handling of TLS certificate verification state when GnuTLS configuration options are dynamically altered. When users change certificate authority settings without restarting the application, the existing TLS sessions continue to operate with the old verification context while new connections may be processed with the updated settings. This inconsistency creates a man-in-the-middle attack vector where attackers can present arbitrary certificates that would normally be rejected by proper certificate validation, but are accepted due to the outdated verification state. The vulnerability is particularly dangerous because it operates silently, allowing attackers to establish fraudulent TLS connections that appear legitimate to the client application. According to CWE classification, this vulnerability maps to CWE-295: Improper Certificate Validation, which specifically addresses failures in validating the authenticity and trustworthiness of certificates in secure communications. The flaw also aligns with ATT&CK technique T1573.002: Encrypted Channel, as it enables attackers to establish compromised encrypted communication channels that bypass normal security controls.
The operational impact of this vulnerability extends beyond simple data interception to encompass complete trust relationship compromise within chat environments. In practice, this means that any user of WeeChat who modifies certificate authority settings without restarting the application becomes vulnerable to active attack scenarios where malicious actors can impersonate legitimate chat servers. The vulnerability affects both system-level and user-defined certificate authority configurations, making it particularly concerning for organizations that rely on custom certificate authorities or internal PKI infrastructure. The attack requires minimal prerequisites - simply changing specific configuration options and maintaining a persistent connection to the target chat server - making it highly exploitable in real-world scenarios. Security professionals should note that this vulnerability demonstrates the importance of proper state management in security-critical applications and the potential for configuration changes to create unexpected security gaps. The issue also highlights the need for robust restart mechanisms or immediate validation procedures when security-related configuration parameters are modified, as outlined in industry best practices for secure configuration management.
Mitigation strategies for CVE-2022-28352 require immediate action including patching to version 3.4.1 or later where the vulnerability has been addressed. Users should ensure that any modification to the weechat.network.gnutls_ca_system or weechat.network.gnutls_ca_user configuration options is followed by a complete WeeChat restart to ensure proper certificate validation state. Organizations should implement monitoring procedures to detect unauthorized configuration changes and establish policies requiring application restarts after security-related parameter modifications. The vulnerability underscores the importance of proper application lifecycle management and the necessity of validating security configurations through restart procedures rather than relying on runtime parameter updates. Additionally, network administrators should consider implementing additional monitoring for suspicious certificate behavior and establish procedures for regular security audits of chat client configurations. This vulnerability serves as a reminder of the critical importance of maintaining consistent security states in network applications and the potential for seemingly benign configuration changes to create significant security risks.