Re: wu-ftpd and /etc/passwd

[sinster () DARKWATER COM (Jon Paul, Nollmann)]

Sprach Chico <chico () SUMMITPRO COM>:
> is wuftpd dependant upon the user account having a valid shell for security
> reasons or just by design?

I can't speak for wuftpd in specific, only its authors can, but it's general
practice to disallow logins when either the password isn't matched or
when the shell is invalid.  It's done for security reasons: it dodges
a lot of errors with the old .rhosts, hosts.equiv, lpd % hack, and
other similar mechanisms.  So, yes: it is done for security reasons
_and_ by design.

(note: it's usually more effective to set the shell to a program that
actually exists but is inoffensive, rather than a program that doesn't
exist... historically, a number of daemons, in an attempt to be
helpful, exec /bin/sh whenever they can't execute the shell in
/etc/passwd.  Most don't exist anymore, but I can't say that none
exist now.  My disable-shell of choice is /bin/false.)

--
Jon Paul Nollmann ne' Darren Senn                      sinster () balltech net
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