CVE-2023-45149 in Talk
Summary
by MITRE • 10/25/2023
Nextcloud talk is a chat module for the Nextcloud server platform. In affected versions brute force protection of public talk conversation passwords can be bypassed, as there was an endpoint validating the conversation password without registering bruteforce attempts. It is recommended that the Nextcloud Talk app is upgraded to 15.0.8, 16.0.6 or 17.1.1. There are no known workarounds for this vulnerability.
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Analysis
by VulDB Data Team • 10/25/2023
The vulnerability identified as CVE-2023-45149 represents a critical security flaw in the Nextcloud Talk chat module that affects the platform's public conversation password protection mechanisms. This issue specifically targets the brute force protection systems that are designed to prevent unauthorized access to public chat conversations through password guessing attacks. The vulnerability exists within the authentication validation endpoint that processes conversation password submissions without properly tracking or registering brute force attempts, effectively undermining the security controls that should protect against automated password cracking attempts.
The technical implementation flaw stems from the absence of proper rate limiting and brute force detection mechanisms within the password validation endpoint. When users attempt to access public conversation rooms, the system validates the provided password but fails to increment or track failed authentication attempts in the brute force protection system. This creates a scenario where attackers can continuously submit password guesses without encountering the typical rate limiting or account lockout mechanisms that would normally prevent such automated attacks. The vulnerability is particularly concerning because it directly impacts the security of public conversations that are accessible to anyone with the conversation link, making them susceptible to unauthorized access through repeated password guessing attempts.
The operational impact of this vulnerability extends beyond simple unauthorized access to compromised conversation data. Attackers can exploit this weakness to gain access to sensitive discussions, personal communications, and potentially confidential information shared within public Nextcloud Talk conversations. This represents a significant risk for organizations that rely on Nextcloud for secure communications, as the vulnerability effectively removes the protective barrier that should exist between public conversations and unauthorized users. The lack of any known workarounds means that organizations must immediately upgrade their systems to prevent exploitation, as there are no temporary mitigation strategies available.
Organizations should prioritize immediate remediation by upgrading to Nextcloud Talk versions 15.0.8, 16.0.6, or 17.1.1, as these releases contain the necessary patches to address the brute force protection bypass. The vulnerability aligns with CWE-307, which addresses inadequate brute force protection mechanisms, and represents a clear violation of security best practices outlined in various cybersecurity frameworks. From an attacker perspective, this vulnerability maps to ATT&CK technique T1110.003, which covers credential stuffing and password spraying attacks, as it removes the protective measures that would normally prevent such automated password guessing attempts. The security implications extend to potential data breaches, privacy violations, and compliance issues that organizations may face if they fail to address this vulnerability promptly, particularly in environments subject to regulatory requirements such as GDPR, HIPAA, or SOX compliance standards.