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AUSCERT External Security Bulletin Redistribution
ESB-2000.166 -- FreeBSD-SA-00:32.bitchx
bitchx port contains client-side vulnerability
7 July 2000
AusCERT Security Bulletin Summary
Vendor: FreeBSD Ports Collection
Operating System: FreeBSD
Impact: Denial of Service
Access Required: Remote
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FreeBSD-SA-00:32 Security Advisory
Topic: bitchx port contains client-side vulnerability
Affects: Ports collection.
Vendor status: Patch released
FreeBSD only: NO
BitchX is a popular IRC client.
II. Problem Description
The bitchx client incorrectly parses string-formatting operators
included as part of channel invitation messages sent by remote IRC
users. This can cause the local client to crash, and may possibly
present the ability to execute arbitrary code as the local user.
The bitchx 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 collections shipped with FreeBSD 4.0 and 3.5 contain
this problem 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 IRC users can cause the local client to crash, and possibly
execute code as the local user.
If you have not chosen to install the bitchx port/package, then
your system is not vulnerable to this problem.
Issue the following bitchx command (e.g. as part of a startup script):
/ignore * invites
which will disable processing of channel invitation messages.
One of the following:
1) Upgrade your entire ports collection and rebuild the bitchx 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. Be
sure to check the file creation date on the package, because the
version number of the software has not changed.
3) download a new port skeleton for the bitchx 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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