Re: CVE Request -- logrotate -- nine issues

[Jan Lieskovsky <jlieskov () redhat com>]

Hi Solar,

  thank you for your reaction.

Solar Designer wrote:
> On Fri, Mar 04, 2011 at 03:08:31PM +0100, Jan Lieskovsky wrote:
> >   we have been contacted by Stefan Fritsch of Debian Security Team
> > about presence of nine security flaws in the logrotate utility
> > (the list is provided below).
>
> I've just skimmed over the list, and I only see one issue that I'd call
> a vulnerability in logrotate, issue #8.  And we need more info on #5.

For issue #5:

If the mail configuration directive is used, an attacker can trick
logrotate into sending arbitrary files by mail, by creating
appropriate hard or soft links.

Hope that's enough, let me know if not.

For the second part:

> The rest, as described, appear to rely on sysadmin error and to assume
> security properties that logrotate never advertised it had.  Specifically,
> logrotate was never declared to be safe to use on untrusted directories,
> and it was an error for a sysadmin to make such an assumption.

We don't mind documenting of this behavior in appropriate places.

Wouldn't like to condescend further into particulars, what is and what
is not a security issue (as this is beyond this post), but according
to our opinion even non-documented incorrect behavior, allowing
malicious actions to be performed on the system, should be considered
a security flaw (regardless if it's advertised or not). Because by applying
your above approach, most of the open source project could just say
'this software is not intended to be run like that.'

Not trying to argue, just saying the disclination like the above
doesn't help anyone.

Either the software has the issues, and they should be fixed,
or it has the issues, and they can't be fixed. Then the software
should not be used and an alternative one should be found.

This is not you would shoot yourself into the foot by accident
(by performing some action). This is about local users', aware
of the deficiencies, ability to conduct such actions on the system,
so they would reach some higher privilege, damage or different
kind of benefit for them.

Hope this helps.

Thanks && Regards, Jan.
--
Jan iankko Lieskovsky / Red Hat Security Response Team

> I don't mind logrotate being enhanced/hardened in this respect, but to
> call these vulnerabilities sounds like a stretch.  Also, even if
> logrotate is hardened, it should not be declared to be safe to use on
> untrusted directories.  It'd be better to explicitly state that it is
> not, to avoid this sort of confusion.
>
> > 5) Issue #5: logrotate: Information disclosure by performing email
> >              notifications
> ...
> > 8) Issue #8: logrotate: TOCTOU race condition by creation of new files 
> > (between
> >              opening the file and moment, final permissions have been 
> >              applied)
> >              [information disclosure]
>
> Alexander