Bug 1549961 (CVE-2018-5733)

Summary:	CVE-2018-5733 dhcp: Reference count overflow in dhcpd allows denial of service
Product:	[Other] Security Response	Reporter:	Adam Mariš <amaris>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	apmukher, dcantrell, dkholia, jpopelka, pemensik, pzhukov, security-response-team, thozza, yozone
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	dhcp 4.1-ESV-R15-P1, dhcp 4.3.6-P1, dhcp 4.4.1	Doc Type:	If docs needed, set a value
Doc Text:	A denial of service flaw was found in the way dhcpd handled reference counting when processing client requests. A malicious DHCP client could use this flaw to trigger a reference count overflow on the server side, potentially causing dhcpd to crash, by sending large amounts of traffic.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2018-03-13 09:03:22 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1549999, 1550000, 1550084, 1550085, 1550246, 1550249
Bug Blocks:	1549964

Description Adam Mariš 2018-02-28 07:32:47 UTC

A malicious client which is allowed to send very large amounts of traffic (billions of packets) to a DHCP server can eventually overflow a 32-bit reference counter, potentially causing dhcpd to crash.

Versions of DHCP affected: 4.1.0 -> 4.1-ESV-R15, 4.2.0 -> 4.2.8, 4.3.0 -> 4.3.6, 4.4.0

Comment 1 Adam Mariš 2018-02-28 07:32:50 UTC

Acknowledgments:

Name: ISC
Upstream: Felix Wilhelm (Google)

Comment 5 Tomas Hoger 2018-02-28 20:31:16 UTC

Public now via upstream advisory.

External References:

https://kb.isc.org/article/AA-01567

Comment 6 Tomas Hoger 2018-02-28 20:31:55 UTC

Created dhcp tracking bugs for this issue:

Affects: fedora-all [bug 1550246]

Comment 8 Tomas Hoger 2018-03-01 12:40:22 UTC

Upstream commit:

https://source.isc.org/cgi-bin/gitweb.cgi?p=dhcp.git;a=commitdiff;h=197b26f25309f947b97a83b8fdfc414b767798f8

Upstream bug (not public):

https://bugs.isc.org/Public/Bug/Display.html?id=47140

Comment 9 errata-xmlrpc 2018-03-09 10:06:11 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 6

Via RHSA-2018:0469 https://access.redhat.com/errata/RHSA-2018:0469

Comment 10 errata-xmlrpc 2018-03-12 18:46:39 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2018:0483 https://access.redhat.com/errata/RHSA-2018:0483