0-Day Fixes

Internet Explorer vulnerability

Report ID: MAPP-CVE20124969
Date Published: 20 September 2012
Date Revised: 24 September 2012
Criticality: Critical
Compromise Type: remote-code-execution
Compromise From: remote
Affected Product/Component:
Internet Explorer 6
Internet Explorer 7
Internet Explorer 8
Internet Explorer 9


A vulnerability in Internet Explorer (IE) could, upon successful exploitation, allow a remote attacker to execute arbitrary code and take complete control of a compromised system.

Detailed Description

Microsoft has released an advisory following the discovery of a vulnerability in Internet Explorer (IE). The vulnerability exists when IE attempts to access a deleted or improperly allocated object, which results in memory corruption. An attacker could take advantage of this condition to gain similar rights as the logged-on user, and possibly take complete control of a compromised system.

To mitigate the impact of this vulnerability, users are advised to implement some workarounds such as applying the relevant Microsoft Fix it solution, or deploying the Enhanced Mitigation Experience Toolkit (EMET). Complete instruction is available from Microsoft Security Advisory 2757760.

F-Secure detects the files taking advantage of this vulnerability as JS:Exploit.JS.Agent.AQ starting in Aquarius database version 2012-09-17_04, and as JS:Exploit.JS.Agent.AR starting in Aquarius database version 2012-09-17_05. Both versions were released on 17 September 2012. Please allow F-Secure products to block the installation of these malicious files, and to remove or disinfect the malicious files if found in the system.

CVE Reference

  • CVE-2012-4969

Detected Exploit

  • JS:Exploit.JS.Agent.AQ
  • JS:Exploit.JS.Agent.AR
  • Aquarius database version 2012-09-17_04 at 20:41:06 UTC
  • Aquarius database version 2012-09-17_04 at 22:43:21 UTC
Release Dates
  • 17 September 2012
Detected Exploit Components
  • Exploit:W32/Defeater.B
  • Exploit:W32/Defeater.C
  • Exploit:W32/Defeater.D
  • Exploit:W32/SWFdloader.R
  • Exploit:W32/SWFdloader.S
  • Exploit:W32/SWFdloader.T
  • Exploit:W32/SWFdloader.U
  • Trojan.Dropper.UIU


Microsoft recommends users to apply the following workarounds to mitigate the impact of the vulnerability until a patch is released:

  • Apply the Microsoft Fix it solution, "Prevent Memory Corruption via ExecCommand in Internet Explorer"
  • Deploy the Enhanced Mitigation Experience Toolkit (EMET)
  • Set Internet security zone setting to "High"
  • Configure Internet Explorer to prompt before running Active Scripting, or disable Active Scripting 

For complete instructions, please refer to Microsoft Security Advisory 2757760


Allow F-Secure Internet Security or F-Secure Anti-Virus to block installation of malicious files, and to remove or disinfect malicious files if found on the system.

Original Source

Microsoft Security Advisory 2757760