CVE-2018-18498
📋 TL;DR
This vulnerability is an integer overflow in image buffer size calculations in Mozilla products, which can lead to out-of-bounds writes. Attackers could exploit this to execute arbitrary code or cause denial of service. It affects Thunderbird, Firefox ESR, and Firefox users running outdated versions.
💻 Affected Systems
- Mozilla Thunderbird
- Mozilla Firefox ESR
- Mozilla Firefox
📦 What is this software?
Firefox by Mozilla
Firefox Esr by Mozilla
Thunderbird by Mozilla
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, or ransomware deployment.
Likely Case
Application crash (denial of service) or limited memory corruption leading to information disclosure.
If Mitigated
No impact if patched; reduced risk with memory protection mechanisms like ASLR/DEP.
🎯 Exploit Status
Exploitation requires triggering the integer overflow via crafted images, but no public exploits are documented.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Thunderbird 60.4, Firefox ESR 60.4, Firefox 64
Vendor Advisory: https://access.redhat.com/errata/RHSA-2018:3831
Restart Required: Yes
Instructions:
1. Update Thunderbird to version 60.4 or later. 2. Update Firefox ESR to version 60.4 or later. 3. Update Firefox to version 64 or later. Use built-in update mechanism or download from official Mozilla sources.
🔧 Temporary Workarounds
Disable image rendering
allPrevent processing of untrusted images by disabling image loading in browser/email client settings.
Use memory protection
allEnable ASLR and DEP at OS level to reduce exploit success probability.
🧯 If You Can't Patch
- Restrict user access to untrusted websites and email attachments.
- Deploy application whitelisting to block execution of malicious code.
🔍 How to Verify
Check if Vulnerable:
Check application version: Thunderbird < 60.4, Firefox ESR < 60.4, or Firefox < 64 indicates vulnerability.Check Version:
Thunderbird: thunderbird --version; Firefox: firefox --versionVerify Fix Applied:
Confirm version is Thunderbird >= 60.4, Firefox ESR >= 60.4, or Firefox >= 64.📡 Detection & Monitoring
Log Indicators:
- Application crashes with memory access violations
- Unexpected process terminations in browser/email logs
Network Indicators:
- Unusual outbound connections from browser processes post-crash
SIEM Query:
source="*browser*" OR source="*thunderbird*" event_type="crash" OR severity="critical"🔗 References
- http://www.securityfocus.com/bid/106168
- https://access.redhat.com/errata/RHSA-2018:3831
- https://access.redhat.com/errata/RHSA-2018:3833
- https://access.redhat.com/errata/RHSA-2019:0159
- https://access.redhat.com/errata/RHSA-2019:0160
- https://bugzilla.mozilla.org/show_bug.cgi?id=1500011
- https://lists.debian.org/debian-lts-announce/2018/12/msg00002.html
- https://security.gentoo.org/glsa/201903-04
- https://usn.ubuntu.com/3844-1/
- https://usn.ubuntu.com/3868-1/
- https://www.debian.org/security/2018/dsa-4354
- https://www.debian.org/security/2019/dsa-4362
- https://www.mozilla.org/security/advisories/mfsa2018-29/
- https://www.mozilla.org/security/advisories/mfsa2018-30/
- https://www.mozilla.org/security/advisories/mfsa2018-31/
- http://www.securityfocus.com/bid/106168
- https://access.redhat.com/errata/RHSA-2018:3831
- https://access.redhat.com/errata/RHSA-2018:3833
- https://access.redhat.com/errata/RHSA-2019:0159
- https://access.redhat.com/errata/RHSA-2019:0160
- https://bugzilla.mozilla.org/show_bug.cgi?id=1500011
- https://lists.debian.org/debian-lts-announce/2018/12/msg00002.html
- https://security.gentoo.org/glsa/201903-04
- https://usn.ubuntu.com/3844-1/
- https://usn.ubuntu.com/3868-1/
- https://www.debian.org/security/2018/dsa-4354
- https://www.debian.org/security/2019/dsa-4362
- https://www.mozilla.org/security/advisories/mfsa2018-29/
- https://www.mozilla.org/security/advisories/mfsa2018-30/
- https://www.mozilla.org/security/advisories/mfsa2018-31/
