CVE-2011-3422 in Mac OS X
Summary
by MITRE
The Keychain implementation in Apple Mac OS X 10.6.8 and earlier does not properly handle an untrusted attribute of a Certification Authority certificate, which makes it easier for man-in-the-middle attackers to spoof arbitrary SSL servers via an Extended Validation certificate, as demonstrated by https access with Safari.
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Analysis
by VulDB Data Team • 01/06/2025
The vulnerability described in CVE-2011-3422 represents a critical flaw in Apple Mac OS X 10.6.8 and earlier versions that affects the system's keychain implementation. This weakness specifically targets how the operating system processes Certification Authority certificates, particularly when handling untrusted attributes within these certificates. The vulnerability stems from insufficient validation mechanisms that fail to properly sanitize or verify the attributes of certificate authority certificates before accepting them as legitimate trust anchors.
The technical exploitation of this vulnerability occurs through a man-in-the-middle attack vector where an attacker can manipulate Extended Validation certificates to deceive the Mac OS X system into accepting fraudulent SSL certificates. When Safari attempts to establish https connections, the flawed keychain implementation does not adequately validate the certificate attributes, allowing attackers to present forged certificates that appear legitimate to the system. This failure in certificate validation creates a trust boundary breach that undermines the entire SSL/TLS security framework that users rely upon for secure web communications.
The operational impact of this vulnerability extends beyond simple certificate validation failures, as it fundamentally compromises the integrity of secure web browsing on affected Mac systems. Attackers can leverage this weakness to perform sophisticated man-in-the-middle attacks against users accessing https websites, potentially intercepting sensitive data including login credentials, personal information, and financial transactions. The vulnerability affects the core trust infrastructure of the operating system, making it particularly dangerous as it operates at a low-level system component that handles all certificate validation processes for secure communications.
This vulnerability aligns with CWE-295, which addresses improper certificate validation, and demonstrates characteristics consistent with ATT&CK technique T1552.001, involving the use of certificate manipulation for credential access. The flaw represents a failure in the certificate chain validation process where the system should be rejecting certificates with untrusted attributes but instead accepts them as valid trust anchors. Organizations using affected Mac OS X versions face significant risk of data breaches and credential theft when users browse the web, as the vulnerability enables attackers to bypass the security mechanisms designed to protect against such attacks.
The recommended mitigation strategies include immediate installation of Apple's security updates that address the certificate validation flaw in the keychain implementation. System administrators should ensure all Mac OS X systems are updated to versions that properly validate certificate attributes and reject certificates with untrusted attributes. Additionally, organizations should consider implementing network monitoring solutions to detect potential man-in-the-middle attacks and educate users about the importance of verifying certificate warnings and maintaining up-to-date systems. The vulnerability highlights the critical importance of proper certificate validation in maintaining secure communications and demonstrates how flaws in system-level trust mechanisms can have widespread implications for user security across all applications that rely on SSL/TLS protection.