Mandrake: chfn Privilege escalation vulnerability
Posted by LinuxSecurity.com Team   
Mandrake In chfn, using a carefully crafted attack sequence, an attacker can exploit a complex file locking and modification race that would allow them to make changes to the /etc/passwd file.

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                Mandrake Linux Security Update Advisory
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Package name:           util-linux
Advisory ID:            MDKSA-2002:047
Date:                   August 8th, 2002
Affected versions:      7.1, 7.2, 8.0, 8.1, 8.2, Corporate Server 1.0.1,
                        Single Network Firewall 7.2
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Problem Description:

 Michal Zalewski found a vulnerability in the util-linux package with
 the chfn utility.  This utility allows users to modify some information
 in the /etc/passwd file, and is installed setuid root.  Using a
 carefully crafted attack sequence, an attacker can exploit a complex
 file locking and modification race that would allow them to make
 changes to the /etc/passwd file.  To successfully exploit this
 vulnerability and obtain privilege escalation, there is a need for some
 administrator interaction, and the password file must over over 4kb in
 size; the attacker's entry cannot be in the last 4kb of the file.
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References:

   http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2002-0638
   http://www.kb.cert.org/vuls/id/405955
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Updated Packages:

 Linux-Mandrake 7.1:
 4c5df1947b62460beb8df7592ef35c6e  7.1/RPMS/util-linux-2.10o-6.1mdk.i586.rpm
 fa4fd5a20bc4cbca324294e3ed712eb1  7.1/SRPMS/util-linux-2.10o-6.1mdk.src.rpm
 Linux-Mandrake 7.2:
 69f07cace4649f3d8326ea8866d95e4f  7.2/RPMS/util-linux-2.10o-6.1mdk.i586.rpm
 fa4fd5a20bc4cbca324294e3ed712eb1  7.2/SRPMS/util-linux-2.10o-6.1mdk.src.rpm

 Mandrake Linux 8.0:
 18a2dc6e74636bdf6b7be146dfa3d6cf  8.0/RPMS/util-linux-2.10s-3.2mdk.i586.rpm
 dd4a423ddc444a202176b09e5251f6fd  8.0/SRPMS/util-linux-2.10s-3.2mdk.src.rpm

 Mandrake Linux 8.0/ppc:
 55e49d1ad321c229a8468f11a43b2fb7  ppc/8.0/RPMS/util-linux-2.11h-3.5mdk.ppc.rpm
 25c5b47d39f8b1c0147930218ddaecd5  ppc/8.0/SRPMS/util-linux-2.11h-3.5mdk.src.rpm

 Mandrake Linux 8.1:
 889ba34fcb46d9c2c2f11cf4fa81dd23  8.1/RPMS/util-linux-2.11h-3.5mdk.i586.rpm
 25c5b47d39f8b1c0147930218ddaecd5  8.1/SRPMS/util-linux-2.11h-3.5mdk.src.rpm

 Mandrake Linux 8.1/ia64:
 2405d127006eef10e1d58e23866f0044  ia64/8.1/RPMS/util-linux-2.11h-3.5mdk.ia64.rpm
 25c5b47d39f8b1c0147930218ddaecd5  ia64/8.1/SRPMS/util-linux-2.11h-3.5mdk.src.rpm

 Mandrake Linux 8.2:
 f137a274c2969ca3b893e96902dee893  8.2/RPMS/losetup-2.11n-4.3mdk.i586.rpm
 c074a07a7f3c3fd92b0be2ebd02dff93  8.2/RPMS/mount-2.11n-4.3mdk.i586.rpm
 420c1537cb8260f984125fd6311dc3d1  8.2/RPMS/util-linux-2.11n-4.3mdk.i586.rpm
 240139061f653327735eb46c3009d245  8.2/SRPMS/util-linux-2.11n-4.3mdk.src.rpm

 Mandrake Linux 8.2/ppc:
 9260b9deba8a1e025e028217f99df3ed  ppc/8.2/RPMS/losetup-2.11n-4.3mdk.ppc.rpm
 abdbafa149f499409c31969ff081e818  ppc/8.2/RPMS/mount-2.11n-4.3mdk.ppc.rpm
 3adff58b4e961fa17c8be1d1224072a2  ppc/8.2/RPMS/util-linux-2.11n-4.3mdk.ppc.rpm
 240139061f653327735eb46c3009d245  ppc/8.2/SRPMS/util-linux-2.11n-4.3mdk.src.rpm

 Corporate Server 1.0.1:
 4c5df1947b62460beb8df7592ef35c6e  1.0.1/RPMS/util-linux-2.10o-6.1mdk.i586.rpm
 fa4fd5a20bc4cbca324294e3ed712eb1  1.0.1/SRPMS/util-linux-2.10o-6.1mdk.src.rpm

 Single Network Firewall 7.2:
 69f07cace4649f3d8326ea8866d95e4f  snf7.2/RPMS/util-linux-2.10o-6.1mdk.i586.rpm
 fa4fd5a20bc4cbca324294e3ed712eb1  snf7.2/SRPMS/util-linux-2.10o-6.1mdk.src.rpm
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Bug IDs fixed (see https://qa.mandrakesoft.com for more information):

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To upgrade automatically, use MandrakeUpdate.  The verification of md5
checksums and GPG signatures is performed automatically for you.

If you want to upgrade manually, download the updated package from one 
of our FTP server mirrors and upgrade with "rpm -Fvh *.rpm".  A list of
FTP mirrors can be obtained from:

   http://www.mandrakesecure.net/en/ftp.php

Please verify the update prior to upgrading to ensure the integrity of
the downloaded package.  You can do this with the command:

  rpm --checksig 

All packages are signed by MandrakeSoft for security.  You can obtain
the GPG public key of the Mandrake Linux Security Team from:

  https://www.mandrakesecure.net/RPM-GPG-KEYS

Please be aware that sometimes it takes the mirrors a few hours to 
update.

You can view other update advisories for Mandrake Linux at:

   http://www.mandrakesecure.net/en/advisories/

MandrakeSoft has several security-related mailing list services that
anyone can subscribe to.  Information on these lists can be obtained by
visiting:

   http://www.mandrakesecure.net/en/mlist.php

If you want to report vulnerabilities, please contact

  security@linux-mandrake.com
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