Mozilla Foundation Security Advisory 2011-40

Code installation through holding down Enter

Announced September 27, 2011 Reporter Mariusz Mlynski Impact Critical Products Firefox, SeaMonkey, Thunderbird Fixed in Firefox 3.6.23

Firefox 7

SeaMonkey 2.4

Thunderbird 3.1.15

Thunderbird 7

Description

Mariusz Mlynski reported that if you could convince a user to hold down the Enter key--as part of a game or test, perhaps--a malicious page could pop up a download dialog where the held key would then activate the default Open action. For some file types this would be merely annoying (the equivalent of a pop-up) but other file types have powerful scripting capabilities. And this would provide an avenue for an attacker to exploit a vulnerability in applications not normally exposed to potentially hostile internet content.

Mariusz also reported a similar flaw with manual plugin installation using the PLUGINSPAGE attribute. It was possible to create an internal error that suppressed a confirmation dialog, such that holding enter would lead to the installation of an arbitrary add-on. (This variant did not affect Firefox 3.6)

References