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: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED UPSTREAM QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: abo, ktdreyer
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Last Closed: 2019-06-08 03:33:26 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On: 1524547, 1524548    
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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.