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             AUSCERT External Security Bulletin Redistribution

          CVE-2015-8605: UDP payload length not properly checked
                              14 January 2016


        AusCERT Security Bulletin Summary

Product:           DHCP
Publisher:         ISC
Operating System:  Windows
                   UNIX variants (UNIX, Linux, OSX)
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2015-8605  

Original Bulletin: 

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CVE-2015-8605: UDP payload length not properly checked


Brian Conry 

Reference Number: 





2016-01-12 14:41 

Last Updated: 

2016-01-12 21:45



Document Version:


Posting date:

12 January 2016

Program Impacted:


Versions affected:

4.0.x, 4.1.x, 4.2.x, 4.1-ESV -> 4.1-ESV-R12, 4.3.0->4.3.3. 3.x may also be 
affected but has not been tested.




- From adjacent networks 2001-2015 Internet Systems Consortium


A badly formed packet with an invalid IPv4 UDP length field can cause a DHCP 
server, client, or relay program to terminate abnormally.


Nearly all IPv4 DHCP clients and relays, and most IPv4 DHCP servers are 
potentially affected.

A server, client, or relay that is built to only be able to process unicast 
packets (i.e. those that have already been processed by the OS UDP/IP stack) 
is not affected, however this build configuration is not normally viable for 
clients and relays. Servers with this build configuration require a relay in 
order to be able to process DISCOVER and other broadcast requests from 

Not all potentially-affected builds will actually be affected, but because it
is difficult to identify or predict those which should be upgraded, our advice
is that all builds should be considered vulnerable.

CVSS Score: 5.7

CVSS Vector: (AV:A/AC:M/Au:N/C:N/I:N/A:C)

For more information on the Common Vulnerability Scoring System and to obtain
your specific environmental score please visit: 


None likely, but in some environments following the advice from 
can substantially reduce the risk by limiting the exposure of a DHCP server to
"controlled" networks and clients.

Active exploits:

No known active exploits.

Solution: Upgrade to the patched release most closely related to your current
version of DHCP. These can all be downloaded from 

DHCP version 4.1-ESV-R12-P1

DHCP version 4.3.3-P1

Acknowledgements: Thanks to Sebastian Poehn from Sophos for reporting this 

Document Revision History:

1.0 Advance Notification 5 January, 2016

1.1 ESV Version name corrected 12 January 2016

2.0 Public Disclosure 12 January, 2016

Related Documents:

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