CVE-2015-5943 in Mac OS X
Summary
by MITRE
SecurityAgent in Apple OS X before 10.11.1 does not prevent synthetic clicks from reaching keychain windows, which allows attackers to bypass intended access restrictions via a crafted app.
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Analysis
by VulDB Data Team • 11/21/2024
The vulnerability identified as CVE-2015-5943 resides within Apple's SecurityAgent component of macOS operating systems prior to version 10.11.1. This flaw represents a critical security oversight in the system's handling of user interface interactions and access control mechanisms. The SecurityAgent serves as a crucial component responsible for managing authentication processes and protecting sensitive system resources including the keychain, which stores passwords, certificates, and other confidential authentication data. When an attacker crafts a malicious application that can generate synthetic mouse clicks, they can exploit this vulnerability to manipulate the keychain window interface directly, bypassing the intended authentication controls.
The technical nature of this vulnerability stems from insufficient input validation and access control enforcement within the SecurityAgent's user interface processing pipeline. Synthetic clicks, which are programmatically generated mouse events that can be triggered by malicious applications without user interaction, are not properly filtered or restricted from reaching the keychain authentication windows. This allows an attacker's crafted application to simulate user interactions that would normally require explicit user consent or authentication. The flaw operates at the system level where the windowing system fails to distinguish between legitimate user-generated events and programmatically generated synthetic events when they target authentication interfaces.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete compromise of the keychain protection mechanisms. Attackers can exploit this weakness to access encrypted passwords, certificates, and other sensitive authentication material stored within the system keychain without proper authorization. This represents a significant breach in the security model of macOS, as the keychain is designed to provide strong protection for credentials and cryptographic keys. The vulnerability effectively undermines the fundamental principle of authentication by allowing automated manipulation of the authentication process through synthetic input events.
From a cybersecurity perspective, this vulnerability aligns with CWE-215, which addresses the exposure of sensitive information through improper input validation, and relates to ATT&CK technique T1555.001 for credentials from password storage modules. The attack vector demonstrates how seemingly benign system components can be leveraged for malicious purposes when proper access controls are not enforced. The vulnerability's exploitation requires minimal user interaction beyond installation of the malicious application, making it particularly dangerous in scenarios where users might unknowingly install compromised software. Organizations and individuals face significant risk as this flaw enables attackers to silently access sensitive authentication data, potentially leading to broader system compromise, credential theft, and unauthorized access to protected resources.
The recommended mitigation strategy involves immediate deployment of Apple's security updates, specifically macOS 10.11.1 and subsequent versions that address this vulnerability through enhanced input filtering and access control enforcement within the SecurityAgent component. System administrators should ensure all macOS installations are updated to versions that contain the necessary patches. Additional protective measures include implementing application whitelisting policies to prevent execution of untrusted applications, monitoring for suspicious synthetic input event patterns, and conducting regular security assessments to identify potential exploitation attempts. The vulnerability highlights the importance of comprehensive input validation and access control enforcement in system components that handle sensitive authentication processes, reinforcing the need for defense-in-depth approaches to protect critical system resources.