FileZilla 3.46.3 - 'Scale factor' Buffer Overflow

How it was found

Summary:

FileZilla in has a problem in the "Scale Factor" field is vulnerable to a Buffer Over Flow attack or a denial attack. Adding random characters in an entry that must accept only Float input type values.

Steps To Reproduce:

A python file of name generatepaste.py was generated for the generation of the chain that allows the overflow, which is the following:

buffer = "\x41" * 5000000 eip= "\x42" * 4 f = open ("generate.txt", "w") f.write(buffer+eip) f.close()

1.- Run python code : python generatepaste.py 2.- Open generate.txt and copy content to clipboard. 3.- Open FileZilla. 4.- Select the Edit menu and then Settings. 5.- Find the Interface section and select Themes. 6.- Paste Clipboard on "Scale Factor" three times. 7.- Click in the icons. 8.- BoF

Supporting Material/References:

[list any additional material (e.g. screenshots, logs, etc.)]

• [attachment / reference] F719632

Impact

An attacker can corrupt FileZilla applications and be a preamble to a much more severe attack.