Bug 1524546 (CVE-2017-17439)

Summary:	CVE-2017-17439 heimdal: NULL pointer dereference via crafted UDP packets
Product:	[Other] Security Response	Reporter:	Andrej Nemec <anemec>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED UPSTREAM	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	abo, ktdreyer
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-06-08 03:33:26 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:	1524547, 1524548
Bug Blocks:

Description Andrej Nemec 2017-12-11 16:38:43 UTC

In Heimdal through 7.4, remote unauthenticated attackers are able to crash the KDC by sending a crafted UDP packet containing empty data fields for client name or realm. The parser would unconditionally dereference NULL pointers in that case, leading to a segmentation fault. This is related to the _kdc_as_rep function in kdc/kerberos5.c and the der_length_visible_string function in lib/asn1/der_length.c.

Upstream issue:

https://github.com/heimdal/heimdal/issues/353

Upstream patch:

https://github.com/heimdal/heimdal/commit/1a6a6e462dc2ac6111f9e02c6852ddec4849b887

References:

http://www.h5l.org/pipermail/heimdal-discuss/2017-August/000259.html

Comment 1 Andrej Nemec 2017-12-11 16:39:08 UTC

Created heimdal tracking bugs for this issue:

Affects: epel-all [bug 1524548]
Affects: fedora-all [bug 1524547]

Comment 2 Product Security DevOps Team 2019-06-08 03:33:26 UTC

This CVE Bugzilla entry is for community support informational purposes only as it does not affect a package in a commercially supported Red Hat product. Refer to the dependent bugs for status of those individual community products.