Zero-day vulnerability in Mozilla Firefox

Heap-based buffer overflow

The vulnerability was reported by Morten Kr├еkvik of Telenor SOC (a Norwegian security vendor). The Nobel Peace Prize website was serving on October 25, 2010 a zero-day exploit against Firefox users. When people accessed the Nobel Peace Prize site they were diverted onto an attack server located in Taiwan which delivered a JavaScript exploit.

Known malware:

Exploit: Belmoo Trojan.

Vulnerability details

Advisory: SB2010102701 - Remote code execution in Mozilla Firefox

Vulnerable component: Mozilla Firefox

CVE-ID: CVE-2010-3765

CVSSv3 score: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C

CWE-ID: CWE-119 - Improper Restriction of Operations within the Bounds of a Memory Buffer


The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to boundary error within nsCSSFrameConstructor::ContentAppended. A remote attacker can create a specially crafted web page containing specially crafted document.write and appendChild calls, cause heap-based buffer overflow and execute arbitrary code on the target system with privileges of the current user.

Successful exploitation of this vulnerability may allow an attacker to compromise vulnerable system.

Note: this vulnerability is being actively exploited.

Known APT campaigns:

Nobel Peace Prize ceremony beach

The group behind this attack was also behind Sunshop.

The attack server located in Taiwan spread malicious HTML file as Trojan.Malscript and the downloaded threat as Backdoor.Belmoo.

Public Exploits: