CVE-2024-7525
📋 TL;DR
This vulnerability allows web extensions with minimal permissions to intercept and modify HTTP responses for any website, bypassing normal security restrictions. It affects Firefox, Firefox ESR, and Thunderbird users running vulnerable versions. Attackers could steal sensitive data or inject malicious content into web pages.
💻 Affected Systems
- Firefox
- Firefox ESR
- Thunderbird
📦 What is this software?
Firefox by Mozilla
Firefox Esr by Mozilla
Firefox Esr by Mozilla
Thunderbird by Mozilla
Thunderbird by Mozilla
⚠️ Risk & Real-World Impact
Worst Case
Attackers could steal authentication tokens, session cookies, financial data, or inject malware into legitimate websites, leading to complete account compromise and data theft.
Likely Case
Malicious extensions could silently intercept and exfiltrate sensitive user data from banking, email, or social media sites without user awareness.
If Mitigated
With proper extension vetting and user awareness, risk is limited to trusted extensions that become compromised or extensions from untrusted sources.
🎯 Exploit Status
Exploitation requires a malicious web extension, which could be distributed through add-on stores or social engineering.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firefox 129+, Firefox ESR 115.14+, Firefox ESR 128.1+, Thunderbird 128.1+, Thunderbird 115.14+
Vendor Advisory: https://www.mozilla.org/security/advisories/mfsa2024-33/
Restart Required: Yes
Instructions:
1. Open browser/mail client. 2. Go to Help > About Firefox/Thunderbird. 3. Allow automatic update or download latest version from mozilla.org. 4. Restart application.
🔧 Temporary Workarounds
Disable or Remove Suspicious Extensions
allRemove any untrusted or unnecessary web extensions to reduce attack surface.
Use Extension Allowlisting
allConfigure enterprise policies to only allow approved extensions.
🧯 If You Can't Patch
- Restrict installation of web extensions to only trusted, verified sources.
- Monitor for unusual network traffic or data exfiltration from browser processes.
🔍 How to Verify
Check if Vulnerable:
Check browser/mail client version against affected versions list.Check Version:
Firefox/Thunderbird: Help > About Firefox/ThunderbirdVerify Fix Applied:
Confirm version is equal to or greater than patched versions listed in fix_official.📡 Detection & Monitoring
Log Indicators:
- Unusual extension activity logs
- Extension permission escalation attempts
Network Indicators:
- Unexpected data exfiltration from browser processes
- Modified HTTP responses to known sites
SIEM Query:
process:firefox.exe AND network_outbound AND (destination_ip NOT IN trusted_ips OR data_size > threshold)🔗 References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1909298
- https://www.mozilla.org/security/advisories/mfsa2024-33/
- https://www.mozilla.org/security/advisories/mfsa2024-34/
- https://www.mozilla.org/security/advisories/mfsa2024-35/
- https://www.mozilla.org/security/advisories/mfsa2024-37/
- https://www.mozilla.org/security/advisories/mfsa2024-38/
