Date: Tue, 11 Jul 2000 15:02:20 -0700
From: FreeBSD Security Advisories security-advisories@freebsd.org
To: BUGTRAQ@SECURITYFOCUS.COM
Subject: FreeBSD Ports Security Advisory: FreeBSD-SA-00:31.canna
[REVISED]
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FreeBSD-SA-00:31 Security Advisory
FreeBSD, Inc.
Topic: Canna port contains remote vulnerability [REVISED]
Category: ports
Module: Canna
Announced: 2000-07-05
Revised: 2000-07-11
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 3500 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).
3) Create a /etc/hosts.canna file on the Canna server and list
the hosts which you wish to allow access to the Canna server. For
example, if you want to allow access via localhost only, include
the following in your /etc/hosts.canna file:
localhost
unix
If you want to allow access via localhost and some-other-host.com,
which has IP address x.y.z.w, include the following:
localhost
unix
x.y.z.w
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/ja-Canna-3.2.2.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/japanese/ja-Canna-3.2.2.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-4-stable/japanese/ja-Canna-3.2.2.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current/japanese/ja-Canna-3.2.2.tgz
ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/alpha/packages-5-current/japanese/ja-Canna-3.2.2.tgz
Note: it may be several days before updated packages are
available.
3) download a new port skeleton for the Canna port from:
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
VI. Revision History
v1.0 2000-07-05 Initial release
v1.1 2000-07-11 Add additional access-control method submitted by KOJIMA Hajime
Correct package URL. Update size of ports collection.
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