CVE-2024-8381
📋 TL;DR
This vulnerability allows attackers to trigger type confusion when accessing properties on objects used as 'with' statement environments in Mozilla products. Successful exploitation could lead to arbitrary code execution or browser crashes. Affected users include anyone running vulnerable versions of Firefox, Firefox ESR, or Thunderbird.
💻 Affected Systems
- Firefox
- Firefox ESR
- Thunderbird
📦 What is this software?
Firefox by Mozilla
Firefox Esr by Mozilla
Firefox Esr by Mozilla
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or malware installation.
Likely Case
Browser crashes (denial of service) or limited memory corruption leading to sandbox escape in browser context.
If Mitigated
No impact if patched; sandboxing may limit damage but not prevent initial exploitation.
🎯 Exploit Status
Exploitation requires JavaScript execution; CVSS 9.8 indicates critical severity with high attack vector.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firefox 130, Firefox ESR 128.2, Firefox ESR 115.15, Thunderbird 128.2, Thunderbird 115.15
Vendor Advisory: https://www.mozilla.org/security/advisories/
Restart Required: Yes
Instructions:
1. Open affected application. 2. Go to Help > About Firefox/Thunderbird. 3. Allow automatic update or download from official site. 4. Restart application.
🔧 Temporary Workarounds
Disable JavaScript
allPrevents exploitation by blocking JavaScript execution.
Use Content Security Policy
allRestrict script execution via CSP headers.
🧯 If You Can't Patch
- Isolate vulnerable systems from internet access.
- Implement application whitelisting to prevent malicious code execution.
🔍 How to Verify
Check if Vulnerable:
Check version in application: Help > About Firefox/Thunderbird.Check Version:
firefox --version or thunderbird --versionVerify Fix Applied:
Confirm version is equal to or greater than patched versions listed.📡 Detection & Monitoring
Log Indicators:
- Application crashes with memory corruption errors
- Unusual JavaScript execution patterns
Network Indicators:
- Malicious JavaScript payloads targeting 'with' statements
SIEM Query:
source="firefox.log" AND ("crash" OR "segfault") OR source="thunderbird.log" AND "type confusion"🔗 References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1912715
- https://www.mozilla.org/security/advisories/mfsa2024-39/
- https://www.mozilla.org/security/advisories/mfsa2024-40/
- https://www.mozilla.org/security/advisories/mfsa2024-41/
- https://www.mozilla.org/security/advisories/mfsa2024-43/
- https://www.mozilla.org/security/advisories/mfsa2024-44/
- https://lists.debian.org/debian-lts-announce/2024/09/msg00012.html
- https://lists.debian.org/debian-lts-announce/2024/09/msg00025.html
