Mozilla Firefox and Thunderbird Uninitialized Memory Information Disclosure (CVE-2013-1675)
Executive & SecOps Summary
SECOPS ASSESSMENTMozilla Firefox before 21.0, Firefox ESR 17.x before 17.0.6, Thunderbird before 17.0.6, and Thunderbird ESR 17.x before 17.0.6
Remote attackers can extract sensitive process memory data via crafted web content, potentially bypassing memory protection mechanisms
Immediately upgrade all affected installations to Firefox 21.0 / Thunderbird 17.0.6 or later
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
Update Firefox and Thunderbird to the latest secure versions using your system package manager.
# For Debian/Ubuntu-based systems
sudo apt-get update
sudo apt-get --only-upgrade install firefox thunderbird -y
# For RedHat/CentOS-based systems
sudo yum update firefox thunderbird -y2. Temporary Workaround & Hardening Configuration
If immediate patching is not feasible, disable JavaScript execution in Thunderbird and restrict access to untrusted external websites.
# Disable JavaScript in Thunderbird user preferences
echo "user_pref('javascript.enabled', false);" >> ~/.thunderbird/*.default/prefs.js3. Log Audit & IoC Verification Commands
Use the following script to audit the installed versions of Firefox and Thunderbird across your endpoints to identify vulnerable deployments.
#!/bin/bash
echo '[*] Auditing Mozilla Product Versions...'
if command -v firefox >/dev/null 2>&1; then
ff_ver=$(firefox --version | awk '{print $3}')
echo "[+] Firefox installed: $ff_ver"
else
echo '[-] Firefox not found.'
fi
if command -v thunderbird >/dev/null 2>&1; then
tb_ver=$(thunderbird --version | awk '{print $3}')
echo "[+] Thunderbird installed: $tb_ver"
else
echo '[-] Thunderbird not found.'
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Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability (CVE-2013-1675) exists in the SVG (Scalable Vector Graphics) zoom event handling component of Mozilla browsers and mail clients. Specifically, the nsDOMSVGZoomEvent::mPreviousScale and nsDOMSVGZoomEvent::mNewScale functions fail to properly initialize their internal data structures (CWE-665). Consequently, uninitialized memory fragments from previous process allocations are exposed when these properties are accessed.
2. Exploitation Mechanics & Attack Scenario
An attacker can exploit this vulnerability by hosting a malicious website or sending an HTML-formatted email containing crafted JavaScript. When a victim visits the site or opens the email, the script triggers an SVG zoom event and reads the uninitialized values of mPreviousScale and mNewScale. Because these values contain remnants of raw process memory, the attacker can reconstruct sensitive data such as cryptographic keys, session tokens, or memory addresses, and exfiltrate them to an external server.
3. Infrastructure & Business Impact
As a CISA KEV-listed vulnerability, this flaw poses a high practical risk. Information disclosure of this nature is frequently utilized in multi-stage exploit chains. By leaking memory layout details, attackers can bypass critical exploit mitigation controls like ASLR (Address Space Layout Randomization), paving the way for reliable Remote Code Execution (RCE) and complete endpoint compromise.
Official Vendor Advisories & References
Mozilla Firefox before 21.0, Firefox ESR 17.x before 17.0.6, Thunderbird before 17.0.6, and Thunderbird ESR 17.x before 17.0.6 do not properly initialize data structures for the nsDOMSVGZoomEvent::mPreviousScale and nsDOMSVGZoomEvent::mNewScale functions, which allows remote attackers to obtain sensitive information from process memory via a crafted web site.
Frequently Asked SecOps Questions (CVE-2013-1675)
FAQQ1. How critical is CVE-2013-1675 and is it actively exploited in the wild?
CVE-2013-1675 is rated CVSS 6.5 (MEDIUM) with a 30-day EPSS exploitation probability of 6.7%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2013-1675?
Primary impacted vendors include mozilla across firefox, thunderbird. Scope summary: Firefox before 21.0, Firefox ESR 17.x before 17.0.6, Thunderbird before 17.0.6, and Thunderbird ESR 17.x before 17.0.6
Q3. What temporary mitigations or workarounds exist for CVE-2013-1675 before patching?
[Mitigation] Immediately upgrade all affected installations to Firefox 21.0 / Thunderbird 17.0.6 or later Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
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