CVE-2014-7991 in Unified Communications Manager
Summary
by MITRE
The Remote Mobile Access Subsystem in Cisco Unified Communications Manager (CM) 10.0(1) and earlier does not properly validate the Subject Alternative Name (SAN) field of an X.509 certificate, which allows man-in-the-middle attackers to spoof VCS core devices via a crafted certificate issued by a legitimate Certification Authority, aka Bug ID CSCuq86376.
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Analysis
by VulDB Data Team • 02/24/2022
The vulnerability described in CVE-2014-7991 represents a critical certificate validation flaw within Cisco Unified Communications Manager's Remote Mobile Access Subsystem. This issue affects versions 10.0(1) and earlier, where the system fails to adequately validate the Subject Alternative Name field in X.509 certificates. The flaw enables man-in-the-middle attackers to impersonate legitimate VCS core devices by presenting malicious certificates issued by trusted Certification Authorities. This vulnerability directly impacts the integrity of secure communications within enterprise voice and video infrastructure, potentially allowing unauthorized access to sensitive communication channels.
The technical root cause of this vulnerability lies in the improper implementation of X.509 certificate validation procedures within the Remote Mobile Access Subsystem. When establishing secure connections, the system should rigorously validate all certificate fields including the Subject Alternative Name to ensure that the certificate is legitimate and appropriate for the intended service. However, Cisco's implementation fails to properly check the SAN field, which contains alternative names that the certificate may be used for, including hostnames, IP addresses, and email addresses. This validation gap creates an attack surface where malicious actors can craft certificates that appear legitimate to the vulnerable system while actually directing traffic to attacker-controlled endpoints.
The operational impact of this vulnerability extends beyond simple certificate validation failure to compromise the entire security architecture of Cisco Unified Communications Manager deployments. Attackers exploiting this vulnerability can intercept, modify, or redirect communications between mobile devices and VCS core components, potentially gaining access to sensitive voice and video communication data. This compromises the confidentiality and integrity of enterprise communications, particularly affecting organizations that rely heavily on unified communications for business-critical operations. The vulnerability affects the fundamental trust model of the system, undermining the security assurances provided by SSL/TLS encryption protocols.
Organizations affected by this vulnerability should prioritize immediate remediation through official Cisco security patches and updates. The recommended mitigation strategy involves upgrading to Cisco Unified Communications Manager versions that address this specific certificate validation flaw. Security teams should also implement additional monitoring measures to detect potential exploitation attempts and consider temporary network segmentation to limit the attack surface. This vulnerability aligns with CWE-295, which specifically addresses improper certificate validation, and represents a significant concern under the ATT&CK framework's credential access and defense evasion tactics. The flaw demonstrates how insufficient certificate validation can create persistent security weaknesses that require comprehensive system updates rather than simple configuration changes to resolve effectively.