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Mozilla Foundation Security Advisory 2012-98

Title: Firefox installer DLL hijacking
Impact: High
Announced: November 20, 2012
Reporter: Robert Kugler
Products: Firefox

Fixed in: Firefox 17.0
  Firefox ESR 10.0.11
  Firefox 18.0
  Firefox ESR 17.0.1
  Firefox ESR 10.0.12


Security researcher Robert Kugler reported that when a specifically named DLL file on a Windows computer is placed in the default downloads directory with the Firefox installer, the Firefox installer will load this DLL when it is launched. In circumstances where the installer is run by an administrator privileged account, this allows for the downloaded DLL file to be run with administrator privileges. This can lead to arbitrary code execution from a privileged account.

Additional vulnerable DLL file names were found and fixed in Firefox 18.0, Firefox ESR 17.0.1, and Firefox ESR 10.0.12 releases.