Microsoft has make clear a now-patched safety flaw impacting Apple macOS that, if efficiently exploited, might have allowed an attacker working as “root” to bypass the working system’s System Integrity Safety (SIP) and set up malicious kernel drivers by loading third-party kernel extensions.
The vulnerability in query is CVE-2024-44243 (CVSS rating: 5.5), a medium-severity bug that was addressed by Apple as a part of macOS Sequoia 15.2 launched final month. The iPhone maker described it as a “configuration subject” that would allow a malicious app to change protected components of the file system.
“Bypassing SIP might result in critical penalties, equivalent to rising the potential for attackers and malware authors to efficiently set up rootkits, create persistent malware, bypass Transparency, Consent and Management (TCC), and broaden the assault floor for extra methods and exploits,” Jonathan Bar Or of the Microsoft Menace Intelligence workforce stated.
SIP, additionally referred to as rootless, is a safety framework that goals to forestall malicious software program put in on a Mac from tampering with the protected components of the working system, together with /System, /usr, /bin, /sbin, /var, and the apps that come pre-installed on the gadget.
It really works by implementing numerous protections towards the basis person account, permitting modification of those protected components solely by processes which can be signed by Apple and have particular entitlements to jot down to system recordsdata, equivalent to Apple software program updates and Apple installers.
The 2 entitlements particular to SIP are under –
- com.apple.rootless.set up, which lifts SIP’s file system restrictions for a course of with this entitlement
- com.apple.rootless.set up.heritable, which lifts SIP’s file system restrictions for a course of and all its baby processes by inheriting the com.apple.rootless.set up entitlement
CVE-2024-44243, the most recent SIP bypass found by Microsoft in macOS after CVE-2021-30892 (Shrootless) and CVE-2023-32369 (Migraine), exploits the Storage Equipment daemon’s (storagekitd) “com.apple.rootless.set up.heritable” entitlement to get round SIP protections.
Particularly, that is achieved by profiting from “storagekitd’s capacity to invoke arbitrary processes with out correct validation or dropping privileges” to ship a brand new file system bundle to /Library/Filesystems – a toddler means of storagekitd – and override the binaries related to the Disk Utility, which might then be triggered throughout sure operations equivalent to disk restore.
“Since an attacker that may run as root can drop a brand new file system bundle to /Library/Filesystems, they will later set off storagekitd to spawn customized binaries, therefore bypassing SIP,” Bar Or stated. “Triggering the erase operation on the newly created file system can bypass SIP protections as nicely.”
The disclosure comes practically three months after Microsoft additionally detailed one other safety flaw in Apple’s Transparency, Consent, and Management (TCC) framework in macOS (CVE-2024-44133, CVSS rating: 5.5) – aka HM Surf – that may very well be exploited to entry delicate information.
“Prohibiting third-party code to run within the kernel can improve macOS reliability, the tradeoff being that it reduces monitoring capabilities for safety options,” Bar Or stated.
“If SIP is bypassed, your complete working system can now not be thought of dependable, and with decreased monitoring visibility, risk actors can tamper with any safety options on the gadget to evade detection.”