OpenPKG Information for VU#149953

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



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OpenPKG Security Advisory                            The OpenPKG Project                   
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

 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

  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]

 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> 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


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Comment: OpenPKG <>


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