Date: Sat, 14 Aug 1999 19:22:10 +0200
From: Wichert Akkerman <wichert@wi.leidenuniv.nl>
To: debian-security-announce@lists.debian.org
Subject: [SECURITY] new version isdnutils fixes exploitable xmonisdn

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We have received reports that the version of xmonisdn as distributed
in the isndutils package from Debian GNU/Linux 2.1 has a security
problem.

Xmonisdn is an X applet that shows the status of the ISDN links. You can
configure it to run two scripts when the left or right mouse button are
clicked on it. Xmonisdn was installed setuid root so that the scripts
could do things like add and delete the default route. However is that
while the scripts were checked for owner root and not writeable by group
or others the scripts are run via the system() library function, which
spawns a shell to run it. This means that the scripts are open to attack
via IFS and/or PATH manipulation.

However, the setuid root isn't necessary anymore as the ISDN system now
offers other ways of preventing dialouts besides by manipulating network
routes.  This can be done by anyone who can access /dev/isdnctrl0 and
/dev/isdninfo. On debian systems those are rw for group dialout, so if
xmonisdn is run by someone in group dialout, they can execute the
necessary isdnctrl commands.

wget url
        will fetch the file for you
dpkg -i file.deb
        will install the referenced file.

Debian GNU/Linux 2.1 alias slink
- -------------------------------

  This version of Debian was released only for Intel, the Motorola
  680x0, the alpha and the Sun sparc architecture.

  Source archives:
    http://security.debian.org/dists/stable/updates/source/isdnutils_3.0-12slink13.diff.gz
      MD5 checksum: 56f4328687b0478c83b49ae8c61d3a24
    http://security.debian.org/dists/stable/updates/source/isdnutils_3.0-12slink13.dsc
      MD5 checksum: 44ecac14b66830e969ce6e09b3f95e1e
    http://security.debian.org/dists/stable/updates/source/isdnutils_3.0.orig.tar.gz
      MD5 checksum: 83cb39ed37747367331ec5b433fc7dda

  Alpha architecture:
    http://security.debian.org/dists/stable/updates/binary-alpha/isdnutils_3.0-12slink13_alpha.deb
      MD5 checksum: 984e4be2224fcf90261139e2576b2d35

  Intel ia32 architecture:
    http://security.debian.org/dists/stable/updates/binary-i386/isdnutils_3.0-12slink13_i386.deb
      MD5 checksum: 6550f5ee476a0c8056acf19f5a1e41fb

  Sun Sparc architecture:
    http://security.debian.org/dists/stable/updates/binary-sparc/isdnutils_3.0-12slink13_sparc.deb
      MD5 checksum: 2da71a182ff8955c0822aa9737095c97

For not yet released architectures please refer to the appropriate
directory ftp://ftp.debian.org/debian/dists/sid/binary-$arch/ .

- --
Debian GNU/Linux      .    Security Managers     .   security@debian.org
              debian-security-announce@lists.debian.org
  Christian Hudon     .     Wichert Akkerman     .     Martin Schulze
<chrish@debian.org>   .   <wakkerma@debian.org>  .   <joey@debian.org>


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