Re: Calife heap corrupt / potential local root exploit

[Ollivier Robert <roberto () keltia freenix fr>]

In-Reply-To: <20040227091921.26210.qmail () www securityfocus com>

> Calife heap corrupt / potential local root exploit
> --------------------------------------------------
> by Leon Juranic a.k.a DownBload <downbload () hotmail com> / II-Labs
>
>
> Version affected(tested): calife-2.8.4c and calife-2.8.5
> - calife can be found at packages.debian.org, FreeBSD 5.0 (security), ...

Thanks you for taking the time to contact me before sending such a mail to Bugtraq.  It is always nice to deal with 
such nice people [NOT!]

> [downbload@localhost downbload]$ calife luser
> Password: "A" x 3000
> Password: real_user_password
> Segmentation fault
> [downbload@localhost downbload]$

Interesting, on which plateform?  I just tried that on FreeBSD 4.9, 5.2 and could not reproduce.

On Linux/Debian, it does segfault. glibc problem?

> - "A" x 3000 will corrupt the heap.
> - If real_user_password isn't correct, calife will do exit()
> - If attacker wants to exploit calife, there must be at least one user "available" in /etc/calife.auth

Do you have such an exploit?  I'd like to see it.

>            pt_pass = (char *) getpass ("Password:");
>            memset (user_pass, '\0', l_size);
>            strcpy (user_pass, pt_pass); // <- BAD CODE

I could have used strlcpy but I assumed (and my reading of the FreeBSD source code confirm it) that getpass(3) was 
doing the size check.

In FreeBSD, it seems not possible to overflow that as the code verify the length.

I'll release 2.8.6 today.

Courtesy seems to go down the gutters these days apparently.

Ollivier, pissed off.