Secunia Advisory: SA13786

Critical: Not critical
Impact: Spoofing
Where: From remote
Solution Status: Unpatched

Software: Mozilla 0.x
Mozilla 1.0
Mozilla 1.1
Mozilla 1.2
Mozilla 1.3
Mozilla 1.4
Mozilla 1.5
Mozilla 1.6
Mozilla 1.7.x
Mozilla Firefox 0.x
Mozilla Firefox 1.x

mikx has discovered a weakness in Mozilla and Mozilla Firefox, which potentially can be exploited by malicious people to trick users into performing unintended actions.

The problem is that popup windows can overlay modal dialogs. This can e.g. be exploited by a malicious web site to hide the information text in a download or security dialog in order to trick a user into accepting it.

Exploitation is more or less convincing depending on the used Windows desktop theme.

The weakness has been confirmed on Mozilla Firefox 1.0 and Mozilla 1.7.5 for Windows.

Solution: Do not take positive actions on dialogs from untrusted sources.