CVE-2016-6445 in Server
Summary
by MITRE
A vulnerability in the Extensible Messaging and Presence Protocol (XMPP) service of the Cisco Meeting Server (CMS) before 2.0.6 and Acano Server before 1.8.18 and 1.9.x before 1.9.6 could allow an unauthenticated, remote attacker to masquerade as a legitimate user. This vulnerability is due to the XMPP service incorrectly processing a deprecated authentication scheme. A successful exploit could allow an attacker to access the system as another user.
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Analysis
by VulDB Data Team • 09/26/2022
The vulnerability identified as CVE-2016-6445 represents a critical authentication flaw within the Extensible Messaging and Presence Protocol implementation of Cisco Meeting Server and Acano Server products. This weakness stems from the XMPP service's improper handling of deprecated authentication mechanisms, creating a pathway for unauthorized remote access. The vulnerability affects specific versions of Cisco Meeting Server prior to 2.0.6 and Acano Server versions before 1.8.18 and 1.9.x before 1.9.6, making these deployments particularly susceptible to exploitation. The flaw allows unauthenticated attackers to impersonate legitimate users, fundamentally compromising the system's user authentication integrity and potentially leading to full system compromise.
The technical root cause of this vulnerability lies in the XMPP service's inadequate validation of authentication tokens and credentials when processing deprecated authentication schemes. When the service encounters authentication requests using obsolete protocols, it fails to properly reject or properly validate these deprecated mechanisms, instead accepting malformed or improperly formatted authentication data. This processing error creates a condition where attackers can craft specific authentication requests that bypass normal security controls, effectively allowing them to assume the identity of existing users within the system. The vulnerability operates at the protocol level, specifically targeting the authentication handshake process between client and server components, making it particularly challenging to detect and prevent through conventional network monitoring approaches.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to potentially escalate privileges and gain deeper system access. Successful exploitation allows attackers to masquerade as legitimate users, which means they can access user-specific data, modify system configurations, and potentially move laterally within the network infrastructure. The remote nature of the attack means that threat actors can exploit this vulnerability from outside the network perimeter, eliminating the need for physical access or insider knowledge. This characteristic aligns with attack patterns documented in the MITRE ATT&CK framework under the credential access and privilege escalation domains, specifically targeting the use of deprecated or weak authentication protocols as a means of system compromise.
Organizations affected by this vulnerability should prioritize immediate remediation through official software updates from Cisco and Acano, specifically upgrading to versions that address the deprecated authentication scheme processing issue. Network segmentation and firewall rule implementation can provide temporary mitigation by restricting access to XMPP service ports, though this approach does not eliminate the underlying vulnerability. Security monitoring should focus on detecting anomalous authentication patterns and unusual user activity that might indicate successful exploitation attempts. The vulnerability demonstrates the importance of proper authentication protocol management and the risks associated with maintaining deprecated security mechanisms within production systems. This case study aligns with CWE-287, which addresses improper authentication issues, and highlights the necessity of regularly reviewing and updating authentication mechanisms to prevent exploitation of legacy protocols that may be vulnerable to manipulation by threat actors.