CVE-2012-6399 in WebEx
Summary
by MITRE
Cisco WebEx 4.1 on iOS does not verify that the server hostname matches a domain name in the subject s Common Name (CN) or subjectAltName field of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via an arbitrary valid certificate, aka Bug ID CSCud94176.
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Analysis
by VulDB Data Team • 05/17/2018
This vulnerability exists in Cisco WebEx 4.1 for iOS clients where the application fails to properly validate SSL/TLS certificates during secure communications. The flaw specifically relates to certificate hostname validation, where the client does not verify that the server hostname matches either the Common Name field or the Subject Alternative Name fields within the X.509 certificate structure. This represents a critical breakdown in the SSL/TLS security protocol implementation that directly violates established security standards and best practices.
The technical nature of this vulnerability stems from improper certificate validation logic within the iOS client application. When establishing secure connections, the application should perform strict hostname verification against the certificate presented by the server. This validation is a fundamental security control that prevents attackers from conducting man-in-the-middle attacks by presenting valid certificates that do not correspond to the intended server. The absence of this validation creates an exploitable condition where any attacker with a valid certificate can impersonate the legitimate server, as the client will accept any certificate without proper hostname matching.
This vulnerability has significant operational impact as it undermines the entire SSL/TLS security model that organizations rely upon for secure communications. Attackers can exploit this weakness to intercept and manipulate communications between WebEx clients and servers, potentially accessing sensitive meeting data, user credentials, or confidential business information. The vulnerability specifically affects enterprise environments where WebEx is used for secure video conferencing and collaboration, making it particularly dangerous for organizations handling sensitive corporate or government data. The attack vector is relatively simple as attackers only need to present a valid certificate with a matching domain name to the target server, bypassing the normal security checks that would normally prevent such impersonation.
The vulnerability aligns with CWE-295, which specifically addresses "Improper Certificate Validation," and represents a failure in implementing proper SSL/TLS certificate validation procedures. From an ATT&CK framework perspective, this vulnerability maps to T1566.001 - "Phishing via Social Engineering" and T1041 - "Exfiltration Over C2 Channel" as attackers can use this weakness to establish malicious connections and exfiltrate data. Organizations should immediately implement mitigations including updating to patched versions of Cisco WebEx, implementing additional network monitoring for suspicious certificate usage, and considering temporary workarounds such as disabling SSL certificate verification only when absolutely necessary and under strict network controls. The recommended approach includes deploying certificate pinning mechanisms where possible, implementing network segmentation to limit exposure, and conducting thorough security assessments to identify any potential exploitation attempts.