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Mozilla Foundation Security Advisory 2005-50

Title: Exploitable crash in InstallVersion.compareTo
Severity: Critical
Reporter: shutdown
Products: Firefox, Mozilla Suite

Fixed in: Firefox 1.0.5
  Mozilla Suite 1.7.10

Description

When InstallVersion.compareTo() is passed an object rather than a string it assumed the object was another InstallVersion without verifying it. When passed a different kind of object the browser would generally crash with an access violation.

shutdown has demonstrated that different javascript objects can be passed on some OS versions to get control over the instruction pointer. We assume this could be developed further to run arbitrary machine code if the attacker can get exploit code loaded at a predictable address.

Update:(2005-12-14) Aviv Raff has posted a proof of concept exploit of this flaw that demonstrates execution of attacker-supplied code on windows.

Workaround

References