CVE-2015-1145 in MacOS X
Summary
by MITRE
The Code Signing implementation in Apple OS X before 10.10.3 does not properly validate signatures, which allows local users to bypass intended access restrictions via a crafted bundle, a different vulnerability than CVE-2015-1146.
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Analysis
by VulDB Data Team • 12/01/2024
The vulnerability identified as CVE-2015-1145 represents a critical flaw in the code signing validation mechanism of Apple's macOS operating system versions prior to 10.10.3. This weakness resides in the fundamental security architecture designed to ensure software integrity and prevent unauthorized code execution. The issue manifests specifically within the code signing implementation where the system fails to properly validate digital signatures associated with software bundles. This failure creates a pathway for malicious actors to exploit the system's trust model and bypass intended security controls that are meant to prevent unauthorized software from executing with elevated privileges.
The technical flaw stems from insufficient signature validation routines that do not adequately verify the authenticity and integrity of code signing certificates within application bundles. Attackers can craft malicious bundles that appear to be legitimate software but contain unauthorized code or modifications that would normally be rejected by proper signature verification. This vulnerability operates at the kernel level of the operating system, where code signing policies are enforced, making it particularly dangerous as it can be exploited to circumvent system security controls without requiring network connectivity or external attack vectors. The flaw specifically affects the way the system processes and validates code signatures, allowing crafted bundles to pass validation checks that should have rejected them based on proper certificate chain verification and signature integrity checks.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass broader system compromise capabilities. Local users who can execute code on the target system can leverage this weakness to bypass security restrictions that are fundamental to macOS security architecture. This includes bypassing Gatekeeper protections, which are designed to prevent execution of unsigned or untrusted software, and potentially gaining unauthorized access to system resources that should be protected. The vulnerability's implications are particularly severe because it allows attackers to execute malicious code with the privileges of the executing user, which could lead to further privilege escalation if the user has administrative rights. This weakness can be exploited to install backdoors, modify system files, or establish persistent access to the compromised system.
Security mitigations for CVE-2015-1145 primarily involve updating to Apple macOS 10.10.3 or later versions where the code signing implementation has been properly patched to address the validation flaw. System administrators should implement comprehensive patch management procedures to ensure all macOS systems are updated promptly. Additionally, organizations should monitor for suspicious software installations and verify the integrity of all application bundles before deployment. The vulnerability aligns with CWE-313, which addresses the improper handling of sensitive data in code signing contexts, and may be related to ATT&CK technique T1553.003, which covers code signing policy bypass. Organizations should also consider implementing additional security controls such as application whitelisting, system integrity protection monitoring, and regular security audits to detect potential exploitation attempts. The fix implemented by Apple addresses the root cause by strengthening the signature validation process and ensuring proper certificate chain verification before granting execution privileges to software bundles.