Bug 1369113 (CVE-2016-2181)

Summary:	CVE-2016-2181 openssl: DTLS replay protection bypass allows DoS against DTLS connection
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, bbaranow, bmaxwell, cdewolf, chazlett, csutherl, dandread, darran.lofthouse, dimitris, dosoudil, erik-fedora, fgavrilo, gzaronik, jaeshin, jawilson, jclere, jondruse, jshepherd, ktietz, lgao, marcandre.lureau, mbabacek, mturk, myarboro, pgier, pjurak, ppalaga, psakar, pslavice, redhat-bugzilla, rjones, rnetuka, rstancel, rsvoboda, sardella, slawomir, tmraz, twalsh, vtunka, weli, yozone
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	openssl 1.0.1u, openssl 1.0.2i	Doc Type:	If docs needed, set a value
Doc Text:	A flaw was found in the Datagram TLS (DTLS) replay protection implementation in OpenSSL. A remote attacker could possibly use this flaw to make a DTLS server using OpenSSL to reject further packets sent from a DTLS client over an established DTLS connection.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-06-08 02:57:41 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:	1369114, 1369115, 1369116, 1377623, 1377624, 1377625, 1377626, 1381814, 1381815
Bug Blocks:	1367347

Description Adam Mariš 2016-08-22 13:52:39 UTC

It was found that when doing handshake/renegotiation, it's possible to bypass DTLS replay protection by sending a record for the next epoch (which does not have to decrypt or have a valid MAC), with a very large sequence number. This means the right hand edge of the window is moved very far to the right, and all subsequent legitimate packets are dropped causing a denial of service.

Upstream patches:

https://github.com/openssl/openssl/commit/5802758eb480c5f14a768f6a061df1dd20aec8c4
https://github.com/openssl/openssl/commit/b77ab018b79a00f789b0fb85596b446b08be4c9d
https://github.com/openssl/openssl/commit/fa75569758298e2930c78989b516cac937118acc

Comment 1 Adam Mariš 2016-08-22 13:53:36 UTC

Created openssl101e tracking bugs for this issue:

Affects: epel-5 [bug 1369116]

Comment 2 Adam Mariš 2016-08-22 13:53:48 UTC

Created openssl tracking bugs for this issue:

Affects: fedora-all [bug 1369114]

Comment 3 Adam Mariš 2016-08-22 13:53:58 UTC

Created mingw-openssl tracking bugs for this issue:

Affects: fedora-all [bug 1369115]

Comment 5 Tomas Hoger 2016-09-22 12:05:12 UTC

Covered now by OpenSSL upstream security advisory and fixed in versions 1.0.1u and 1.0.2i.


DTLS replay protection DoS (CVE-2016-2181)
==========================================

Severity: Low

A flaw in the DTLS replay attack protection mechanism means that records that
arrive for future epochs update the replay protection "window" before the MAC
for the record has been validated. This could be exploited by an attacker by
sending a record for the next epoch (which does not have to decrypt or have a
valid MAC), with a very large sequence number. This means that all subsequent
legitimate packets are dropped causing a denial of service for a specific
DTLS connection.

OpenSSL 1.0.2 DTLS users should upgrade to 1.0.2i
OpenSSL 1.0.1 DTLS users should upgrade to 1.0.1u

This issue was reported to OpenSSL on 21st November 2015 by the OCAP audit team.
The fix was developed by Matt Caswell of the OpenSSL development team.


External References:

https://www.openssl.org/news/secadv/20160922.txt

Comment 8 errata-xmlrpc 2016-09-27 13:54:05 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 6
  Red Hat Enterprise Linux 7

Via RHSA-2016:1940 https://rhn.redhat.com/errata/RHSA-2016-1940.html