CVE-2025-3091 in mbCONNECT24
Summary
by MITRE • 06/24/2025
An low privileged remote attacker in possession of the second factor for another user can login as that user without knowledge of the other user`s password.
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Analysis
by VulDB Data Team • 06/27/2025
This vulnerability represents a critical authentication bypass flaw that undermines the security of multi-factor authentication systems. The issue stems from improper session management and authentication flow validation where an attacker with access to a victim's second factor token can exploit a weakness in the authentication process to impersonate that user. The vulnerability specifically affects systems where second factor authentication is implemented but lacks proper user verification mechanisms during the authentication flow, creating a pathway for unauthorized access. This type of vulnerability is classified under CWE-287 which deals with improper authentication scenarios and falls into the ATT&CK technique T1078.004 for valid accounts and T1566.002 for phishing with social engineering. The flaw allows for privilege escalation and lateral movement within networks where such authentication systems are deployed.
The technical implementation of this vulnerability typically involves a race condition or state management error in the authentication service where the system fails to properly validate that the second factor belongs to the user attempting to authenticate. When a user provides their second factor, the system should verify that this factor corresponds to the intended user account before proceeding with authentication. However, in affected systems, the authentication service accepts the second factor without proper correlation to the user context, allowing an attacker to leverage another user's second factor token to gain access to that user's account. This creates a scenario where the attacker can bypass password requirements entirely, relying solely on the possession of the second factor. The vulnerability is particularly dangerous because it requires minimal attacker capabilities - only access to another user's second factor, which can be obtained through social engineering, physical access, or other means of compromise.
The operational impact of this vulnerability extends far beyond simple unauthorized access. Organizations may experience complete account takeover scenarios where attackers can access sensitive data, modify system configurations, or escalate privileges within the affected systems. The vulnerability is especially concerning in enterprise environments where privileged accounts may be targeted, potentially leading to full system compromise. Security teams must consider the cascading effects of such an attack, as compromised accounts often have elevated permissions and can provide access to critical infrastructure. This vulnerability can also enable advanced persistent threat campaigns where attackers maintain long-term access to systems without detection, as the authentication bypass may not trigger standard security alerts. The impact is amplified when considering that many organizations rely on second factor authentication as a primary security control, making this vulnerability particularly damaging to overall security posture.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term architectural improvements. Organizations should implement proper user context validation during authentication flows, ensuring that second factor tokens are correlated to specific user accounts before granting access. This includes implementing session binding mechanisms that tie authentication tokens to specific user contexts and account identifiers. The implementation should follow security best practices outlined in NIST SP 800-63B for authentication system security and the ISO/IEC 27001 information security management standards. Organizations should also deploy monitoring solutions that can detect anomalous authentication patterns, particularly when second factors are used in unexpected contexts or from unusual locations. Regular security testing including penetration testing and vulnerability assessments should be conducted to identify similar authentication bypass vulnerabilities. Additionally, implementing multi-factor authentication systems with proper challenge-response mechanisms and account lockout policies can help reduce the window of opportunity for exploitation. The remediation process should include code reviews focusing on authentication flows, proper error handling, and session management practices to ensure that such vulnerabilities do not exist in other parts of the authentication infrastructure.