CVE-2003-0355 in Safari
Summary
by MITRE
Safari 1.0 Beta 2 (v73) and earlier does not validate the Common Name (CN) field for X.509 Certificates, which could allow remote attackers to spoof certificates.
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Analysis
by VulDB Data Team • 06/14/2018
The vulnerability described in CVE-2003-0355 represents a critical flaw in Apple Safari 1.0 Beta 2 and earlier versions that undermines the fundamental security mechanism of SSL/TLS certificate validation. This weakness specifically targets the validation of the Common Name field within X.509 certificates, which serves as a crucial component in establishing trust between web browsers and servers. The implementation fails to properly verify that the certificate's Common Name matches the domain name of the website being accessed, creating a significant security gap that malicious actors can exploit to conduct man-in-the-middle attacks.
The technical flaw stems from Safari's inadequate certificate validation process where the browser does not perform proper hostname verification against the certificate's Common Name field. This failure aligns with CWE-295, which addresses improper certificate validation, and specifically relates to the absence of hostname checking in the certificate validation chain. When a user navigates to a website, the browser should verify that the certificate presented by the server corresponds to the domain name being accessed, but Safari's implementation bypassed this critical step, allowing attackers to present certificates with arbitrary Common Names that do not match the target domain.
The operational impact of this vulnerability extends far beyond simple certificate validation failure, as it fundamentally compromises the integrity of secure communications between users and web servers. Attackers can exploit this weakness by obtaining or generating certificates with misleading Common Names that match legitimate websites, enabling them to intercept and modify traffic without detection. This vulnerability directly maps to techniques described in the MITRE ATT&CK framework under T1573, which covers "Tunneling" and "Proxy" techniques used for data exfiltration and man-in-the-middle attacks. The consequences include potential data theft, session hijacking, and the ability to impersonate trusted websites without raising security alerts.
Security professionals should recognize this vulnerability as part of a broader category of SSL/TLS implementation flaws that have plagued web browsers since the early days of secure web communications. The lack of proper certificate validation in Safari 1.0 Beta 2 represents a failure to implement the fundamental security principle of certificate chain validation, which should include hostname verification as mandated by RFC 2818. Organizations and users should immediately update to patched versions of Safari, as this vulnerability could be exploited by attackers with minimal technical expertise to conduct successful phishing attacks and eavesdropping operations. The remediation involves implementing proper certificate validation mechanisms that verify the Common Name field against the requested hostname, ensuring that certificates can only be trusted when they properly authenticate the server they represent.