Description:
Florian Lohoff discovered a bug [0] in dhcrelay which is part of the
ISC DHCP Distribution [1]. The bug is causing the relay agent to
send a continuing packet storm towards the configured DHCP server(s)
in case of a malicious BOOTP packet. The Common Vulnerabilities and
Exposures (CVE) project assigned the id CAN-2003-0039 [2] to the
problem.
Our update does not ultimately fix the root cause of the problem.
However, it improves dhcrelay's compliance to RFC1542 [10] by
rigorously supporting the requirements listed in section "4.1.1
BOOTREQUEST Messages" and thus limiting havoc wreaked to the network:
"The relay agent MUST silently discard BOOTREQUEST messages whose
'hops' field exceeds the value 16. A configuration option SHOULD be
provided to set this threshold to a smaller value if desired by the
network manager. The default setting for a configurable threshold
SHOULD be 4."
The added configuration option is named "-c". Its default value to 4
and the allowed range of the value is between 0 and 16.
Please check whether you are affected by running "<prefix>/bin/rpm
-q dhcpd". If you have the "dhcpd" package installed and its version
is affected (see above), we recommend that you immediately upgrade
it (see Solution). [3][4]
Solution:
Select the updated source RPM appropriate for your OpenPKG release
[5][6], fetch it from the OpenPKG FTP service [7][8] or a mirror
location, verify its integrity [9], build a corresponding binary RPM
from it [3] and update your OpenPKG installation by applying the binary
RPM [4]. For the current release OpenPKG 1.1, perform the following
operations to permanently fix the security problem (for other releases
adjust accordingly).
$ ftp ftp.openpkg.org
ftp> bin
ftp> cd release/1.2/UPD
ftp> get dhcpd-3.0.1rc11-1.2.1.src.rpm
ftp> bye
$ <prefix>/bin/rpm -v --checksig dhcpd-3.0.1rc11-1.2.1.src.rpm
$ <prefix>/bin/rpm --rebuild dhcpd-3.0.1rc11-1.2.1.src.rpm
$ su -
# <prefix>/bin/rpm -Fvh <prefix>/RPM/PKG/dhcpd-3.0.1rc11-1.2.1.*.rpm
________________________________________________________________________
For security reasons, this advisory was digitally signed with
the OpenPGP public key "OpenPKG <openpkg (at) openpkg (dot) org [email concealed]>" (ID 63C4CB9F)
of the OpenPKG project which you can find under the official URL
http://www.openpkg.org/openpkg.pgp or on http://keyserver.pgp.com/. To
check the integrity of this advisory, verify its digital signature by
using GnuPG (http://www.gnupg.org/). For instance, pipe this message to
the command "gpg --verify --keyserver keyserver.pgp.com".
________________________________________________________________________
Hash: SHA1
________________________________________________________________________
OpenPKG Security Advisory The OpenPKG Project
http://www.openpkg.org/security.html http://www.openpkg.org
openpkg-security (at) openpkg (dot) org [email concealed] openpkg (at) openpkg (dot) org [email concealed]
OpenPKG-SA-2003.012 19-Feb-2003
________________________________________________________________________
Package: dhcpd
Vulnerability: denial of service (packet storm)
OpenPKG Specific: no
Affected Releases: Affected Packages: Corrected Packages:
OpenPKG CURRENT <= dhcpd-3.0.1rc11-20030116 >= dhcpd-3.0.1rc11-20030219
OpenPKG 1.2 <= dhcpd-3.0.1rc11-1.2.0 >= dhcpd-3.0.1rc11-1.2.1
OpenPKG 1.1 <= dhcpd-3.0.1rc9-1.1.1 >= dhcpd-3.0.1rc9-1.1.2
Affected Releases: Dependent Packages: none
Description:
Florian Lohoff discovered a bug [0] in dhcrelay which is part of the
ISC DHCP Distribution [1]. The bug is causing the relay agent to
send a continuing packet storm towards the configured DHCP server(s)
in case of a malicious BOOTP packet. The Common Vulnerabilities and
Exposures (CVE) project assigned the id CAN-2003-0039 [2] to the
problem.
Our update does not ultimately fix the root cause of the problem.
However, it improves dhcrelay's compliance to RFC1542 [10] by
rigorously supporting the requirements listed in section "4.1.1
BOOTREQUEST Messages" and thus limiting havoc wreaked to the network:
"The relay agent MUST silently discard BOOTREQUEST messages whose
'hops' field exceeds the value 16. A configuration option SHOULD be
provided to set this threshold to a smaller value if desired by the
network manager. The default setting for a configurable threshold
SHOULD be 4."
The added configuration option is named "-c". Its default value to 4
and the allowed range of the value is between 0 and 16.
Please check whether you are affected by running "<prefix>/bin/rpm
-q dhcpd". If you have the "dhcpd" package installed and its version
is affected (see above), we recommend that you immediately upgrade
it (see Solution). [3][4]
Solution:
Select the updated source RPM appropriate for your OpenPKG release
[5][6], fetch it from the OpenPKG FTP service [7][8] or a mirror
location, verify its integrity [9], build a corresponding binary RPM
from it [3] and update your OpenPKG installation by applying the binary
RPM [4]. For the current release OpenPKG 1.1, perform the following
operations to permanently fix the security problem (for other releases
adjust accordingly).
$ ftp ftp.openpkg.org
ftp> bin
ftp> cd release/1.2/UPD
ftp> get dhcpd-3.0.1rc11-1.2.1.src.rpm
ftp> bye
$ <prefix>/bin/rpm -v --checksig dhcpd-3.0.1rc11-1.2.1.src.rpm
$ <prefix>/bin/rpm --rebuild dhcpd-3.0.1rc11-1.2.1.src.rpm
$ su -
# <prefix>/bin/rpm -Fvh <prefix>/RPM/PKG/dhcpd-3.0.1rc11-1.2.1.*.rpm
________________________________________________________________________
References:
[0] http://marc.theaimsgroup.com/?l=bugtraq&m=104310927813830&w=2
[1] http://www.isc.org/products/DHCP/dhcp-v3.html
[2] http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2003-0039
[3] http://www.openpkg.org/tutorial.html#regular-source
[4] http://www.openpkg.org/tutorial.html#regular-binary
[5] ftp://ftp.openpkg.org/release/1.1/UPD/dhcpd-3.0.1rc9-1.1.2.src.rpm
[6] ftp://ftp.openpkg.org/release/1.2/UPD/dhcpd-3.0.1rc11-1.2.1.src.rpm
[7] ftp://ftp.openpkg.org/release/1.1/UPD/
[8] ftp://ftp.openpkg.org/release/1.2/UPD/
[9] http://www.openpkg.org/security.html#signature
[10] ftp://ftp.rfc-editor.org/in-notes/rfc1542.txt
________________________________________________________________________
For security reasons, this advisory was digitally signed with
the OpenPGP public key "OpenPKG <openpkg (at) openpkg (dot) org [email concealed]>" (ID 63C4CB9F)
of the OpenPKG project which you can find under the official URL
http://www.openpkg.org/openpkg.pgp or on http://keyserver.pgp.com/. To
check the integrity of this advisory, verify its digital signature by
using GnuPG (http://www.gnupg.org/). For instance, pipe this message to
the command "gpg --verify --keyserver keyserver.pgp.com".
________________________________________________________________________
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