CVE-2009-1682 in Safari
Summary
by MITRE
Apple Safari before 4.0 does not properly check for revoked Extended Validation (EV) certificates, which makes it easier for remote attackers to trick a user into accepting an invalid certificate.
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Analysis
by VulDB Data Team • 09/06/2019
The vulnerability described in CVE-2009-1682 represents a critical flaw in Apple Safari's certificate validation mechanism that undermines the security assurances provided by Extended Validation certificates. This issue affects Safari versions prior to 4.0 and stems from the browser's failure to properly verify the revocation status of EV certificates, creating a significant attack surface for man-in-the-middle and phishing operations.
The technical flaw resides in Safari's certificate validation logic where the browser does not adequately check Certificate Revocation Lists or Online Certificate Status Protocol responses for EV certificates. Extended Validation certificates are designed to provide stronger assurance of identity by requiring extensive verification of the certificate applicant's identity before issuance. However, when these certificates are revoked due to security breaches, compromise, or other issues, the validation process should immediately flag them as invalid. The absence of proper revocation checking means that even if an EV certificate has been compromised or revoked, Safari may still accept it as valid, thereby undermining the trust model that EV certificates are meant to establish.
This vulnerability creates substantial operational impact by enabling remote attackers to exploit the trust relationship between users and websites. Attackers can obtain revoked EV certificates from compromised Certificate Authority accounts or through other means and present them to users through various attack vectors including DNS spoofing, SSL stripping, or by compromising web servers. Users who trust the visual indicators provided by EV certificates may be misled into believing they are connecting to legitimate websites, when in fact they are communicating with malicious actors. The attack is particularly effective because EV certificates display distinctive visual elements such as green address bars and organization names that users often trust implicitly, making the deception more convincing.
The implications of this vulnerability align with several cybersecurity frameworks and attack patterns. From a CWE perspective, this represents a weakness in certificate validation (CWE-295) where proper validation of certificate status is not performed, and specifically relates to improper certificate validation during TLS negotiation. The vulnerability also maps to ATT&CK technique T1552.001 for credentials from password storage and T1552.006 for credentials in registry, as attackers can exploit the trust model to gain access to user credentials through deceptive certificate presentations. Organizations using affected Safari versions face increased risk of credential theft, data breaches, and successful phishing campaigns that leverage the false sense of security provided by revoked EV certificates.
Mitigation strategies should include immediate upgrade to Safari 4.0 or later versions where proper EV certificate revocation checking has been implemented. Additionally, system administrators should monitor and enforce certificate validation policies, implement network-level monitoring for suspicious certificate usage, and educate users about the importance of verifying website authenticity beyond visual indicators. Organizations should also consider implementing additional security layers such as HSTS enforcement, certificate pinning, and regular security audits of certificate usage to reduce the attack surface. The vulnerability underscores the critical importance of maintaining up-to-date security software and the necessity of robust certificate management practices within enterprise environments.