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Debian Security Advisory: mailx local exploit

Mar 13, 2001, 23:12 (1 Talkback[s])
(Other stories by Wichert Akkerman)

Date: Tue, 13 Mar 2001 23:05:57 +0100
From: Wichert Akkerman wichert@cistron.nl
To: debian-security-announce@lists.debian.org
Subject: [SECURITY] [DSA-044-1] mailx local exploit


Debian Security Advisory DSA-044-1                                      security@debian.org
http://www.debian.org/security/                                   Wichert Akkerman 
March 13, 2001


Package        : mailx
Problem type   : buffer overflow
Debian-specific: no
The mail program (a simple tool to read and send email) as distributed with Debian GNU/Linux 2.2 has a buffer overflow in the input parsing code. Since mail is installed setgid mail by default this allowed local users to use it to gain access to mail group.

Since the mail code was never written to be secure fixing it properly would mean a large rewrite. Instead of doing this we decided to no longer install it setgid. This means that it can no longer lock your mailbox properly on systems for which you need group mail to write to the mailspool, but it will still work for sending email.

This has been fixed in mailx version 8.1.1-10.1.5. If you have suidmanager installed you can also make this manually with the following command:

suidregister /usr/bin/mail root root 0755

wget url
        will fetch the file for you
dpkg -i file.deb
        will install the referenced file.
Debian GNU/Linux 2.2 alias potato

Potato was released for alpha, arm, i386, m68k, powerpc and sparc.

Source archives:
http://security.debian.org/dists/stable/updates/main/source/mailx_8.1.1-10.1.5.diff.gz
MD5 checksum: bfc7cf2139819cb25750cddc4c939931
http://security.debian.org/dists/stable/updates/main/source/mailx_8.1.1-10.1.5.dsc
MD5 checksum: 564992494f775638eeae0bc3427c513a
http://security.debian.org/dists/stable/updates/main/source/mailx_8.1.1.orig.tar.gz
MD5 checksum: c779002cb043b57fd5198ec2032cacb0

Alpha architecture:
http://security.debian.org/dists/stable/updates/main/binary-alpha/mailx_8.1.1-10.1.5_alpha.deb
MD5 checksum: 37edc09cfe3c96994dfeff42c42fe9b2

ARM architecture:
http://security.debian.org/dists/stable/updates/main/binary-arm/mailx_8.1.1-10.1.5_arm.deb
MD5 checksum: 8c50598bb486d62ad312730083e674f1

Intel ia32 architecture:
http://security.debian.org/dists/stable/updates/main/binary-i386/mailx_8.1.1-10.1.5_i386.deb
MD5 checksum: 18d30b35676fa9887a626c46909c9d9d

Motorola 680x0 architecture:
http://security.debian.org/dists/stable/updates/main/binary-m68k/mailx_8.1.1-10.1.5_m68k.deb
MD5 checksum: 86ef8e4cf85e1634096ba52ed1f10987

PowerPC architecture:
http://security.debian.org/dists/stable/updates/main/binary-powerpc/mailx_8.1.1-10.1.5_powerpc.deb
MD5 checksum: 97ec939047cdb7025095701df840838e

Sun Sparc architecture:
http://security.debian.org/dists/stable/updates/main/binary-sparc/mailx_8.1.1-10.1.5_sparc.deb
MD5 checksum: 7b22c952196f2e604558d4b12ef23932

These files will be moved into ftp://ftp.debian.org/debian/dists/stable/*/binary-$arch/ soon.

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


For apt-get: deb http://security.debian.org/ stable/updates main
For dpkg-ftp: ftp://security.debian.org/debian-security dists/stable/updates/main
Mailing list: debian-security-announce@lists.debian.org
Package info: `apt-cache show <pkg>' and http://packages.debian.org/<pkg>