OpenPKG Information for VU#149953

ISC "dhcrelay" fails to limit hop count when malicious bootp packet is received

Status

Affected

Vendor Statement

No statement is currently available from the vendor regarding this vulnerability.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Vendor References

None

Addendum

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________________________________________________________________________

OpenPKG Security Advisory                            The OpenPKG Project
http://www.openpkg.org/security.html              http://www.openpkg.org
openpkg-security@openpkg.org                         openpkg@openpkg.org
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@openpkg.org>" (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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