CVE-2018-4086 in iOS
Summary
by MITRE
An issue was discovered in certain Apple products. iOS before 11.2.5 is affected. macOS before 10.13.3 is affected. tvOS before 11.2.5 is affected. watchOS before 4.2.2 is affected. The issue involves the "Security" component. It allows remote attackers to spoof certificate validation via crafted name constraints.
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Analysis
by VulDB Data Team • 02/02/2021
This vulnerability resides within Apple's security infrastructure and affects multiple operating systems including iOS, macOS, tvOS, and watchOS. The flaw specifically targets the certificate validation mechanism, which is fundamental to establishing secure communications and authenticating entities within the Apple ecosystem. The vulnerability enables attackers to manipulate the certificate validation process through the use of crafted name constraints, potentially allowing them to bypass security checks that should prevent unauthorized certificate issuance or validation.
The technical nature of this vulnerability stems from improper handling of name constraints within X.509 certificates during the validation process. Name constraints are used to limit the domain names or other identifiers that can be included in certificates issued by a certificate authority. When these constraints are improperly validated, attackers can craft certificates that appear legitimate but contain malicious name constraints that bypass the normal validation procedures. This flaw operates at the core of PKI (Public Key Infrastructure) trust mechanisms, where certificate validation is critical for maintaining secure communications and preventing man-in-the-middle attacks.
The operational impact of this vulnerability is significant as it affects a broad range of Apple devices and operating systems, spanning mobile, desktop, and television platforms. Attackers could exploit this weakness to perform certificate spoofing attacks, potentially intercepting encrypted communications or impersonating legitimate services. The vulnerability affects versions prior to the specified security updates, meaning that users operating on these older versions remain exposed to potential exploitation. This creates a substantial risk for organizations and individuals who may not have updated their systems, as the attack surface includes email communications, web browsing, and any application relying on secure certificate validation.
The vulnerability aligns with CWE-295 which addresses "Improper Certificate Validation" and represents a classic example of how certificate validation flaws can compromise entire security architectures. From an attack perspective, this vulnerability maps to techniques described in the MITRE ATT&CK framework under the "Credential Access" and "Initial Access" phases, where attackers can leverage compromised certificates to gain unauthorized access to systems or data. The impact extends beyond simple certificate validation bypass to potentially enable more sophisticated attacks including SSL/TLS interception, service impersonation, and credential theft. Organizations should implement immediate patch management procedures to address this vulnerability, as the risk of exploitation increases with the number of affected systems in their environment.
This vulnerability demonstrates the critical importance of proper certificate validation implementation in security infrastructure and highlights how even subtle flaws in cryptographic validation can have wide-ranging consequences. The affected versions represent a significant portion of Apple's deployed user base, making this vulnerability particularly concerning from a threat landscape perspective. The remediation requires updating to the specified secure versions of each operating system, as Apple has addressed this specific weakness in their security updates. Security teams should prioritize this vulnerability in their assessment and remediation schedules, particularly in environments where Apple devices are used for sensitive communications or critical infrastructure operations.