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FreeBSD Ports Security Advisory: FreeBSD-SA-00:31.canna

Jul 06, 2000, 19:32 (0 Talkback[s])

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Date: Wed, 5 Jul 2000 16:13:41 -0700
From: FreeBSD Security Advisories security-advisories@freebsd.org
To: BUGTRAQ@SECURITYFOCUS.COM
Subject: FreeBSD Ports Security Advisory: FreeBSD-SA-00:31.canna

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FreeBSD-SA-00:31                                           Security Advisory
                                                                FreeBSD, Inc.

Topic:          Canna port contains remote vulnerability

Category:       ports
Module:         Canna
Announced:      2000-07-05
Affects:        Ports collection.
Corrected:      2000-06-29
Credits:        Shadow Penguin Security
 
Vendor status:  Contacted
FreeBSD only:   NO
I. Background

Canna is a Kana-Kanji conversion server.

II. Problem Description

The Canna server contains an overflowable buffer which may be exploited by a remote user to execute arbitrary code on the local system as user 'bin'.

The Canna port is not installed by default, nor is it "part of FreeBSD" as such: it is part of the FreeBSD ports collection, which contains over 3400 third-party applications in a ready-to-install format. The ports collection shipped with FreeBSD 3.5 contains this vulnerability since it was discovered after the release.

FreeBSD makes no claim about the security of these third-party applications, although an effort is underway to provide a security audit of the most security-critical ports.

III. Impact

Remote users can run arbitrary code as user 'bin' on the local system. Depending on the local system configuration, the attacker may be able to upgrade privileges further by exploiting local vulnerabilities.

If you have not chosen to install the Canna port/package, then your system is not vulnerable to this problem.

IV. Workaround

One of the following:

1) Deinstall the Canna port/package, if you you have installed it.

2) Consider limiting remote access to the Canna server using ipfw(8) or ipf(8).

V. Solution

One of the following:

1) Upgrade your entire ports collection and rebuild the Canna port.

2) Deinstall the old package and install a new package dated after the correction date, obtained from:

ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-3-stable/japanese/Canna-3.2.2.tar.gz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/japanese/Canna-3.2.2.tar.gz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-4-stable/japanese/Canna-3.2.2.tar.gz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/japanese/Canna-3.2.2.tar.gz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-5-current/japanese/Canna-3.2.2.tar.gz

Note: it may be several days before updated packages are available.

3) download a new port skeleton for the Canna port from:

http://www.freebsd.org/ports/

and use it to rebuild the port.

4) Use the portcheckout utility to automate option (3) above. The portcheckout port is available in /usr/ports/devel/portcheckout or the package can be obtained from:

ftp://ftp.freebsd.org/pub/FreeBSD/ports/packages/devel/portcheckout-1.0.tgz

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