Microsoft has make clear a now-patched security flaw impacting Apple macOS that, if efficiently exploited, might 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 concern” that would allow a malicious app to change protected components of the file system.
“Bypassing SIP might result in critical penalties, resembling growing the potential for attackers and malware authors to efficiently set up rootkits, create persistent malware, bypass Transparency, Consent and Management (TCC), and increase the assault floor for added methods and exploits,” Jonathan Bar Or of the Microsoft Risk Intelligence crew mentioned.
SIP, additionally referred to as rootless, is a security 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 varied protections towards the foundation consumer account, permitting modification of those protected components solely by processes which can be signed by Apple and have particular entitlements to put in writing to system recordsdata, resembling 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 baby 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 making the most of “storagekitd’s capability to invoke arbitrary processes with out correct validation or dropping privileges” to ship a brand new file system bundle to /Library/Filesystems – a baby technique of storagekitd – and override the binaries related to the Disk Utility, which might then be triggered throughout sure operations resembling disk restore.
“Since an attacker that may run as root can drop a brand new file system bundle to /Library/Filesystems, they’ll later set off storagekitd to spawn customized binaries, therefore bypassing SIP,” Bar Or mentioned. “Triggering the erase operation on the newly created file system can bypass SIP protections as effectively.”
The disclosure comes practically three months after Microsoft additionally detailed one other security 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 knowledge.
“Prohibiting third-party code to run within the kernel can enhance macOS reliability, the tradeoff being that it reduces monitoring capabilities for security options,” Bar Or mentioned.
“If SIP is bypassed, the whole working system can now not be thought of dependable, and with diminished monitoring visibility, menace actors can tamper with any security options on the gadget to evade detection.”
