-----BEGIN PGP SIGNED MESSAGE-----
AUSCERT External Security Bulletin Redistribution
ESB-1999.028 -- NetBSD Security Advisory 1999-004
traceroute can create untraceable packet floods
01 March 1999
The NetBSD Foundation, Inc. has released the following advisory concerning a
vulnerability in traceroute. This vulnerability may allow remote users to
create untraceable packet floods.
- --------------------------BEGIN INCLUDED TEXT--------------------
- -----BEGIN PGP SIGNED MESSAGE-----
NetBSD Security Advisory 1999-004
Topic: traceroute can create untraceable packet floods
Version: NetBSD 1.3.3 and prior; NetBSD-current until 19990217
Severity: Unauthorized users can flood remote hosts with a forged
By feeding traceroute(1) with invalid arguments the time delay
between packets sent is set to zero resulting in all packets sent out
very fast, possibly flooding the remote host with packets containing
a false source address.
When setting the wait time for each packet the argument was not
sanity checked possibly causing select(2) to return immediately
after sending out a packet instead of waiting for reply. The
return value of a select(2) call was not properly checked causing
a flood of packets to be sent to the remote host. This is
exacerbated by the fact that traceroute(1) allowed non-root users
to set the source address for these packets, allowing them to appear
to come from any address, possibly making it extremely difficult to
identify the real source of the flood.
Solutions and Workarounds
A patch is available for the NetBSD 1.3.3 source, which fixes the
above problems. You may find this patch on the NetBSD ftp server:
The patch contains details on how to apply it. As a temporary measure,
you can allow only privileged users to run traceroute by disabling its
chmod u-s /usr/sbin/traceroute
Thanks go out to the members of the Bugtraq mailing list where this
problem was first discussed. Also, many thanks to Curt Sampson
<cjs@NetBSD.ORG> who fixed the problem in NetBSD-current and to
Hubert Feyrer <hubertf@NetBSD.ORG> for the patch to NetBSD-1.3.3
and the coordination of this security advisory.
Information about NetBSD and NetBSD security can be found at
http://www.NetBSD.ORG/ and http://www.NetBSD.ORG/Security/.
Copyright 1999, The NetBSD Foundation, Inc. All Rights Reserved.
$NetBSD: NetBSD-SA1999-004.txt,v 1.1 1999/02/28 00:45:56 mrg Exp $
- -----BEGIN PGP SIGNATURE-----
- -----END PGP SIGNATURE-----
- --------------------------END INCLUDED TEXT--------------------
This security bulletin is provided as a service to AusCERT's members. As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to use any or all of this information is
the responsibility of each user or organisation, and should be done so in
accordance with site policies and procedures.
NOTE: This is only the original release of the security bulletin. It will
not be updated when updates to the original are made. If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the original authors to ensure that the information is still current.
Contact information for the authors of the original document is included
in the Security Bulletin above. If you have any questions or need further
information, please contact them directly.
Previous advisories and external security bulletins can be retrieved from:
If you believe that your system has been compromised, contact AusCERT or
your representative in FIRST (Forum of Incident Response and Security
Internet Email: email@example.com
Facsimile: (07) 3365 7031
Telephone: (07) 3365 4417 (International: +61 7 3365 4417)
AusCERT personnel answer during Queensland business hours
which are GMT+10:00 (AEST).
On call after hours for emergencies.
-----BEGIN PGP SIGNATURE-----
-----END PGP SIGNATURE-----