Microsoft has make clear a now-patched safety flaw impacting Apple macOS that, if efficiently exploited, may have allowed an attacker operating 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 problem” that would allow a malicious app to change protected elements of the file system.
“Bypassing SIP may result in critical penalties, corresponding to rising the potential for attackers and malware authors to efficiently set up rootkits, create persistent malware, bypass Transparency, Consent and Management (TCC), and develop the assault floor for added strategies and exploits,” Jonathan Bar Or of the Microsoft Risk Intelligence staff stated.
SIP, additionally referred to as rootless, is a safety framework that goals to stop malicious software program put in on a Mac from tampering with the protected elements of the working system, together with /System, /usr, /bin, /sbin, /var, and the apps that come pre-installed on the machine.
It really works by implementing numerous protections in opposition to the foundation person account, permitting modification of those protected elements solely by processes which are signed by Apple and have particular entitlements to jot down to system recordsdata, corresponding to Apple software program updates and Apple installers.
The 2 entitlements particular to SIP are beneath –
- 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 little one processes by inheriting the com.apple.rootless.set up entitlement
CVE-2024-44243, the newest SIP bypass found by Microsoft in macOS after CVE-2021-30892 (Shrootless) and CVE-2023-32369 (Migraine), exploits the Storage Package daemon’s (storagekitd) “com.apple.rootless.set up.heritable” entitlement to get round SIP protections.
Particularly, that is achieved by benefiting from “storagekitd’s potential to invoke arbitrary processes with out correct validation or dropping privileges” to ship a brand new file system bundle to /Library/Filesystems – a baby strategy of storagekitd – and override the binaries related to the Disk Utility, which may then be triggered throughout sure operations corresponding 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 properly.”
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 might 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 entire working system can not be thought-about dependable, and with decreased monitoring visibility, menace actors can tamper with any safety options on the machine to evade detection.”