Full Disclosure: Re: /etc/passwd corruption

[John Jacobs <flamdugen () hotmail com>]

Hi,

> On ubuntu lucid, I found a way to add corrupted entries to /etc/passwd
> e.g. "AAA\n", but not to /etc/shadow. Does someone know a way to use
> that for privilege escalation? What is the "+" line handling in
> /etc/passwd for?
Please see "man 5 passwd", I suspect you'll be able to leverage this to 
create a system account in /etc/passwd.  The file will likely need to contain 
a crypt()'d password.  Not exactly sure how PAM will handle.

The Ubuntu gents are normally really good about fixing security issues so
you'll likely want to get in touch with them so they can fix it up.

Cheers,
John
                                          
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