Re: RAZOR advisory: Linux util-linux chfn local root vulnerability

[Andreas Beck <becka () uni-duesseldorf de>]

Andrew Pimlott <andrew () pimlott net> wrote:
> > > If he is smart, he will check whether the file is open (eg with fuser)
> > Not really. The file does not have to be open to be present in the system.
> > It is prefectly possible to leave a dangling root-owned file several
> > times, 
> Correct, but: the admin should still verify that it is not open
> before deleting it (in his cron job).  

As long as there is no atomic "check-if-file-is-open-and-if-not-delete-it"
this just makes exploitation harder by introducing another race condition.


CU, Andy

-- 
= Andreas Beck                    |  Email :  <becka () bedatec de>             =