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AUSCERT External Security Bulletin Redistribution
ESB-2000.165 -- FreeBSD-SA-00:31.canna
Canna port contains remote vulnerability
7 July 2000
AusCERT Security Bulletin Summary
Vendor: FreeBSD Ports Collection
Operating System: FreeBSD
Impact: Execute Arbitrary Code/Commands
Access Required: Remote
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FreeBSD-SA-00:31 Security Advisory
Topic: Canna port contains remote vulnerability
Affects: Ports collection.
Credits: Shadow Penguin Security
Vendor status: Contacted
FreeBSD only: NO
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.
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.
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)
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:
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:
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