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The vulnerability exists in the nsCSSFrameConstructor::ContentAppended function within Firefox’s layout engine. When JavaScript appends multiple child nodes to a DOM element using appendChild, the function fails to update an internal index correctly while creating frames for the new content. This incorrect tracking leads to a state where the engine creates duplicate frames for the same DOM node. The subsequent interaction with these duplicate frames corrupts the browser’s memory, creating a use-after-free condition. A remote attacker can craft a malicious web page containing specific JavaScript that manipulates the DOM to trigger this flaw. Successful exploitation allows the execution of arbitrary code within the context of the current user, as demonstrated by the Belmoo malware in October 2010.
Platform: Mozilla Firefox
Version: 3.5.14
Vulnerability: Memory Corruption
Severity: Critical
date: 2010-10
Prediction: 2010-10-26
What Undercode Say:
searchsploit "Firefox 3.5.14"
grep -r "nsCSSFrameConstructor" /firefox/src/
python -c "print('CVE-2010-3765 POC')"
// Malicious JS triggering the flaw
var e = document.getElementById('container');
for (var i = 0; i < 100; i++) {
var newChild = document.createElement('div');
e.appendChild(newChild);
// Triggers incorrect index tracking
}
How Exploit:
Crafted HTML/JavaScript
Memory corruption
Arbitrary code execution
Protection from this CVE
Update Firefox immediately
Disable JavaScript temporarily
Use NoScript extension
Impact:
Remote Code Execution
System Compromise
Malware Infection
🎯Let’s Practice Exploiting & Learn Patching For Free:
Sources:
Reported By: www.cve.org
Extra Source Hub:
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