Bug 1504045 (CVE-2017-15088)

Summary:	CVE-2017-15088 krb5: Buffer overflow in get_matching_data()
Product:	[Other] Security Response	Reporter:	Adam Mariš <amaris>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	abokovoy, apintea, bkundal, bmaxwell, carnil, cdewolf, chazlett, csutherl, darran.lofthouse, dimitris, dominik.mierzejewski, dosoudil, dpal, fgavrilo, gzaronik, jawilson, jclere, jondruse, jplans, jshepherd, j, lgao, mbabacek, mturk, myarboro, nalin, npmccallum, pgier, pjurak, pkis, ppalaga, psakar, pslavice, rharwood, rnetuka, rstancel, rsvoboda, sbose, security-response-team, ssorce, sstavrev, twalsh, vtunka, weli
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
URL:	https://github.com/krb5/krb5/pull/707
Whiteboard:
Fixed In Version:	krb5 1.16	Doc Type:	If docs needed, set a value
Doc Text:	A stack based buffer overflow was found in the get_matching_data() function, when reading the principal's certificate during pkinit preauthentication. If the Certifcate Authority's subject line is sufficiently long, an attacker able to have a specially crafted certificate signed could crash the authentication process, such as kinit, or, possibly, run arbitrary code.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2018-01-10 11:15:20 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:	1506622
Bug Blocks:	1504046

Description Adam Mariš 2017-10-19 11:44:38 UTC

A buffer overflow vulnerability was found in get_matching_data() function when both the CA cert and the user cert have a long subject affecting krb5 that includes certauth plugin. Attack requires a validated certificate with a long subject and issuer, and a "pkinit_cert_match" string attribute on some principal in the database. A remote code execution exploit might also require that the attacker gets to choose the contents of the issuer in the validated cert.

Bug report:

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=871698

Comment 5 Cedric Buissart 2017-10-26 13:07:57 UTC

Created krb5 tracking bugs for this issue:

Affects: fedora-all [bug 1506622]

Comment 6 Adam Mariš 2017-10-31 12:03:06 UTC

Upstream patch:

https://github.com/krb5/krb5/commit/fbb687db1088ddd894d975996e5f6a4252b9a2b4

Comment 9 Cedric Buissart 2018-01-10 11:14:16 UTC

Statement:

This issue affects the versions of krb5 as shipped with Red Hat Enterprise Linux 7. Red Hat Product Security has rated this issue as having Moderate security impact. A future update may address this issue. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.