A Serious macOS Flaw Bypassed Security to Expose Passwords and Decrypt Apps
Apple’s macOS is widely regarded for its robust security architecture, but a recently disclosed vulnerability serves as a critical reminder that no operating system is entirely immune to threats. A significant security flaw was discovered that could have allowed malicious applications to bypass core macOS security features, granting them full, unrestricted access to the macOS Keychain and the ability to decrypt sensitive iOS applications.
This vulnerability highlights the ongoing cat-and-mouse game between platform developers and cybercriminals, emphasizing the need for constant vigilance and timely software updates.
What Was the Vulnerability?
The security flaw, identified as CVE-2023-42924, resided within a fundamental component of macOS known as CoreTrust. This system is responsible for verifying the digital signatures of applications, acting as a gatekeeper that ensures only legitimate, Apple-notarized software can run with full privileges.
The vulnerability created a loophole that allowed an attacker to craft a special digital signature. When an application with this malicious signature was launched, it could fool CoreTrust into granting it elevated privileges it should never have had. Essentially, a malicious app could masquerade as a trusted one, allowing it to circumvent foundational security checks built deep into the operating system.
The Real-World Impact: More Than Just Passwords
The consequences of this flaw were severe, primarily affecting two critical areas of the Apple ecosystem:
Complete Keychain Access: The macOS Keychain is a secure digital vault that stores your most sensitive information, including website passwords, credit card numbers, Wi-Fi passwords, private encryption keys, and secure notes. By exploiting this vulnerability, a malicious application could gain the ability to read all data stored in the Keychain without requiring your master password or any user interaction. This would allow an attacker to silently exfiltrate a user’s entire digital life.
iOS App Decryption: For developers and security researchers, a compromised Mac could be used for another nefarious purpose. The flaw made it possible to decrypt and analyze sensitive iOS applications that were being examined on the Mac. This could lead to the theft of intellectual property, the discovery of further vulnerabilities within the app, or the reverse-engineering of proprietary code.
The most dangerous aspect of this attack is its stealth. Because the exploit bypassed core security prompts, a user would have no visible warning that their data was being compromised. The malicious app could operate silently in the background, siphoning off sensitive information.
Your Best Defense: Actionable Security Tips
While Apple has patched this specific vulnerability, the principles of good digital hygiene remain your strongest defense against both current and future threats.
Update Your Mac Immediately: The most critical step is to ensure your system is running the latest version of macOS. Apple addressed CVE-2023-42924 in macOS Sonoma 14.2, macOS Ventura 13.6.3, and macOS Monterey 12.7.2. If you have not updated, your system remains vulnerable. Navigate to System Settings > General > Software Update to install the patch.
Download Apps Only from Trusted Sources: The primary way this vulnerability would be exploited is through a trojanized application. Stick to downloading software directly from the Mac App Store or from the official websites of reputable developers. Avoid third-party app aggregators and torrent sites.
Leverage Built-in macOS Protections: Be thankful for Gatekeeper and XProtect, Apple’s built-in anti-malware tools. Gatekeeper ensures that apps are notarized by Apple before they run, while XProtect actively scans for and blocks known malware. Keeping your system updated ensures these tools have the latest security definitions.
Scrutinize Permission Requests: Even with a patched system, be wary of applications asking for broad permissions. If a simple utility app asks for access to your contacts, documents, or system-level controls, treat it with suspicion. Never grant permissions to an application you do not fully trust.
Consider a Reputable Security Suite: For an added layer of protection, a well-regarded antivirus or anti-malware solution for Mac can help detect and block threats that might slip through the cracks, providing real-time scanning and protection.
This vulnerability serves as a powerful reminder that proactive security is essential. While Apple works to secure its platforms, users play a crucial role in maintaining their own digital safety. Stay informed, stay vigilant, and always keep your systems up to date.
Source: https://www.helpnetsecurity.com/2025/09/04/macos-gcore-vulnerability-cve-2025-24204/
