How the CVE Works:
CVE-2025-31187 is a critical vulnerability in macOS that allows malicious apps to bypass file system protections and modify restricted directories. The flaw stems from improper access controls in the kernel’s file system layer, enabling privilege escalation. Attackers exploit this by crafting a malicious application that manipulates system calls to gain write access to protected areas (e.g., /System, /Library). Successful exploitation could lead to root persistence, data theft, or OS compromise. Apple patched this in macOS Ventura 13.7.5, Sonoma 14.7.5, and Sequoia 15.4 by hardening file system permission checks.
DailyCVE Form:
Platform: macOS
Version: Ventura <13.7.5
Vulnerability: FS modification bypass
Severity: Critical
Date: 03/31/2025
What Undercode Say:
Analytics:
- CVSS 4.0: 9.8 (AV:L/AC:L/AT:N/PR:N/UI:N/S:C/C:H/I:H/A:H)
- Exploitability: High (PoC likely in wild)
- Patch Gap: ~30 days from disclosure
Exploit Commands:
1. Check vulnerable version:
sw_vers | grep "ProductVersion"
2. Malicious app payload (concept):
let rootPaths = [bash]
rootPaths.forEach { try? Data().write(to: URL(fileURLWithPath: $0 + "/malicious")) }
Protection:
1. Immediate patch:
softwareupdate --install --all
2. Sandboxing enforcement:
sudo spctl --master-enable
3. Monitor FS changes:
sudo fs_usage -w -f filesys | grep "modify"
Code Fix (Apple’s Patch):
- Kernel now validates `root` write requests via `kauth` scope checks:
if (vnode_isprotected(vp) && !kauth_cred_issuser(cred)) { return EPERM; }
Detection Rule (YARA):
rule macos_cve202531187_exploit {
strings:
$syscall = "openat" nocase
$path = "/System" nocase
condition:
all of them
}
Mitigation:
- Restrict app installations to App Store only:
sudo defaults write /Library/Preferences/com.apple.security GKAutoRearm -bool YES
- Enable SIP (System Integrity Protection):
csrutil enable
References:
Reported By: https://nvd.nist.gov/vuln/detail/CVE-2025-31187
Extra Source Hub:
Undercode
