PoC Released for CVE-2023-42942 – a macOS Root Privilege Escalation Vulnerability
An independent security researcher has published details and proof-of-concept (PoC) code for a macOS vulnerability (CVE-2023-42942) that could be exploited for root privilege escalation.
The Discovery of CVE-2023-42942
The security defect was identified and reported by security researcher Mickey Jin in April last year, with a patch available since the release of macOS Sonoma 14.1 in October.
In its advisory, Apple notes that the flaw allowed a malicious app may be able to gain root privileges and that improved handling of symlinks resolved the issue.
The Vulnerability: A Race to Root Privileges
The vulnerability’s essence lay in a race condition within xpcroleaccountd, a system service integral to macOS’s security infrastructure. Mickey Jin’s exploration into this vulnerability unveiled a multi-step process to exploit the flaw, demonstrating both the vulnerability’s potential impact and the ingenuity required to exploit it.
-
The Setup: A malicious actor plants a specially crafted Apple-signed XPC service bundle in a temporary location.
-
Triggering the Race: They send an XPC empty message to this bundle, starting the race within the xpcroleaccountd service.
-
The Switch: Right before a crucial API call (copyfile), the malicious bundle is replaced with a symbolic link pointing to a different, attacker-controlled file.
-
Tricking Verification: The replaced file passes Apple’s signature checks by masquerading as legitimate.
-
Payload Delivery with a Kick: Now, the attacker’s malicious code executes, not with regular user permissions, but with full root powers!
Today, Mickey Jin published details on the PoC exploit code needed to exploit the CVE-2023-42942 flaw.
Implications
The ability to gain root privileges on a macOS system is the hacker equivalent of hitting the jackpot. Root access allows:
- Unrestricted modification of system files and settings
- Installation of further malware or backdoors
- Monitoring and interception of sensitive data
- Taking complete control of the compromised machine.
This analysis of CVE-2023-42942 offers a technical perspective on a significant macOS vulnerability. The exploit highlights the risks of privilege escalation and the continuous need for vigilance in patching and the adoption of robust security practices.
