CVE-2017-5398
📋 TL;DR
CVE-2017-5398 is a memory corruption vulnerability in Thunderbird and Firefox that could allow attackers to execute arbitrary code on affected systems. This affects users running vulnerable versions of Firefox (<52), Firefox ESR (<45.8), Thunderbird (<52), and Thunderbird ESR (<45.8).
💻 Affected Systems
- Mozilla Firefox
- Mozilla Firefox ESR
- Mozilla Thunderbird
- Mozilla Thunderbird ESR
📦 What is this software?
Firefox by Mozilla
Firefox by Mozilla
Thunderbird by Mozilla
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Application crash or denial of service, with potential for limited code execution in targeted attacks.
If Mitigated
Minimal impact if systems are patched, isolated, or have memory protection controls enabled.
🎯 Exploit Status
Memory corruption vulnerabilities in browsers/email clients are frequently weaponized. The CVSS 9.8 score indicates high exploitability.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firefox 52, Firefox ESR 45.8, Thunderbird 52, Thunderbird ESR 45.8
Vendor Advisory: https://www.mozilla.org/en-US/security/advisories/
Restart Required: Yes
Instructions:
1. Open the application. 2. Go to Help > About. 3. Allow automatic update. 4. Restart when prompted. For enterprise deployments, use your standard patch management system.
🔧 Temporary Workarounds
Disable JavaScript
allReduces attack surface by disabling JavaScript execution in Thunderbird
In Thunderbird: Edit > Preferences > Advanced > General > Config Editor > Set javascript.enabled to false
Network Segmentation
allRestrict network access to vulnerable systems
🧯 If You Can't Patch
- Isolate affected systems from internet and untrusted networks
- Implement application whitelisting to prevent execution of unauthorized code
🔍 How to Verify
Check if Vulnerable:
Check application version in Help > About menu. Compare against affected versions.Check Version:
On Linux: thunderbird --version or firefox --version. On Windows: Check Help > About.Verify Fix Applied:
Verify version is Firefox ≥52, Firefox ESR ≥45.8, Thunderbird ≥52, or Thunderbird ESR ≥45.8.📡 Detection & Monitoring
Log Indicators:
- Application crash logs
- Memory access violation errors
- Unexpected process termination
Network Indicators:
- Unusual outbound connections from browser/email client
- Suspicious download patterns
SIEM Query:
source="*thunderbird*" OR source="*firefox*" AND (event_type="crash" OR error="memory" OR error="corruption")🔗 References
- http://rhn.redhat.com/errata/RHSA-2017-0459.html
- http://rhn.redhat.com/errata/RHSA-2017-0461.html
- http://rhn.redhat.com/errata/RHSA-2017-0498.html
- http://www.securityfocus.com/bid/96651
- http://www.securitytracker.com/id/1037966
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=1332550%2C1332597%2C1338383%2C1321612%2C1322971%2C1333568%2C1333887%2C1335450%2C1325052%2C1324379%2C1336510
- https://security.gentoo.org/glsa/201705-06
- https://security.gentoo.org/glsa/201705-07
- https://www.debian.org/security/2017/dsa-3805
- https://www.debian.org/security/2017/dsa-3832
- https://www.mozilla.org/security/advisories/mfsa2017-05/
- https://www.mozilla.org/security/advisories/mfsa2017-06/
- https://www.mozilla.org/security/advisories/mfsa2017-07/
- https://www.mozilla.org/security/advisories/mfsa2017-09/
- http://rhn.redhat.com/errata/RHSA-2017-0459.html
- http://rhn.redhat.com/errata/RHSA-2017-0461.html
- http://rhn.redhat.com/errata/RHSA-2017-0498.html
- http://www.securityfocus.com/bid/96651
- http://www.securitytracker.com/id/1037966
- https://bugzilla.mozilla.org/buglist.cgi?bug_id=1332550%2C1332597%2C1338383%2C1321612%2C1322971%2C1333568%2C1333887%2C1335450%2C1325052%2C1324379%2C1336510
- https://security.gentoo.org/glsa/201705-06
- https://security.gentoo.org/glsa/201705-07
- https://www.debian.org/security/2017/dsa-3805
- https://www.debian.org/security/2017/dsa-3832
- https://www.mozilla.org/security/advisories/mfsa2017-05/
- https://www.mozilla.org/security/advisories/mfsa2017-06/
- https://www.mozilla.org/security/advisories/mfsa2017-07/
- https://www.mozilla.org/security/advisories/mfsa2017-09/
