Bug 1301488 (CVE-2015-7744)

Summary:	CVE-2015-7744 yaSSL, wolfSSL: insufficient hardening of RSA-CRT implementation (Oracle MySQL CPU Jan 2016)
Product:	[Other] Security Response	Reporter:	Martin Prpič <mprpic>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	abaron, aortega, apevec, ayoung, chrisw, dallan, databases-maint, dciabrin, fdinitto, fweimer, gkotton, hhorak, jdornak, jorton, jschluet, jstanek, lhh, lpeer, markmc, mbayer, mmaslano, mmuzila, rbryant, rohara, sclewis, tdecacqu, yeylon
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	mysql 5.5.46, mysql 5.6.27, mariadb 5.5.46, mariadb 10.1.9, mariadb 10.0.22, wolfSSL 3.6.8, yaSSL 2.3.8	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2016-02-08 09:28:43 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:
Bug Blocks:	1301514

Description Martin Prpič 2016-01-25 09:05:39 UTC

Vulnerability in the MySQL Server component of Oracle MySQL (subcomponent: Server: Security: Encryption). Supported versions that are affected are 5.5.45 and earlier and 5.6.26 and earlier. Very difficult to exploit vulnerability allows successful unauthenticated network attacks via multiple protocols. Successful attack of this vulnerability can result in unauthorized read access to a subset of MySQL Server accessible data. 

External References:

http://www.oracle.com/technetwork/topics/security/cpujan2016verbose-2367956.html

Comment 1 Martin Prpič 2016-01-25 09:33:37 UTC

Created mariadb tracking bugs for this issue:

Affects: fedora-all [bug 1301518]

Comment 2 Martin Prpič 2016-01-25 09:33:49 UTC

Created community-mysql tracking bugs for this issue:

Affects: fedora-all [bug 1301517]

Comment 3 Martin Prpič 2016-01-25 09:34:00 UTC

Created mariadb-galera tracking bugs for this issue:

Affects: fedora-all [bug 1301519]

Comment 5 Tomas Hoger 2016-02-08 09:28:43 UTC

This actually is not a MySQL flaw, but a flaw in embedded yaSSL library.  Mitre CVE description is:

  wolfSSL (formerly CyaSSL) before 3.6.8 does not properly handle faults
  associated with the Chinese Remainder Theorm (CRT) process when allowing
  ephemeral key exchange without low memory optimizations on a server, which
  makes it easier for remote attackers to obtain private RSA keys by capturing
  TLS handshakes, aka a Lenstra attack.

References:

https://wolfssl.com/wolfSSL/Blog/Entries/2015/9/17_Two_Vulnerabilities_Recently_Found%2C_An_Attack_on_RSA_using_CRT_and_DoS_Vulnerability_With_DTLS.html
https://www.wolfssl.com/wolfSSL/Docs-yassl-changelog.html
https://people.redhat.com/~fweimer/rsa-crt-leaks.pdf
https://securityblog.redhat.com/2015/09/02/factoring-rsa-keys-with-tls-perfect-forward-secrecy/

Issue was fixed in MySQL by updating embedded yaSSL library to version 2.3.8:

https://github.com/mysql/mysql-server/commit/b9768521bdeb1a8069c7b871f4536792b65fd79b

MySQL and MariaDB packages as included in Red Hat products do not use embedded yaSSL library and rather use system OpenSSL.  Therefore, they were not affected by this issue.