Bug 833118 (CVE-2011-5094)

Summary:	CVE-2011-5094 nss: DoS via repeated SSL session renegotiations
Product:	[Other] Security Response	Reporter:	Vincent Danen <vdanen>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	Keywords:	Security
Target Milestone:	---
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Hardware:	All
OS:	Linux
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Fixed In Version:		Doc Type:	Bug Fix
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Last Closed:	2021-06-11 21:04:34 UTC	Type:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	716425

Description Vincent Danen 2012-06-18 16:05:56 UTC

URL: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2011-5094
Assigned: 20120616
Reference: URL: http://www.openwall.com/lists/oss-security/2011/07/08/2
Reference: URL: http://www.ietf.org/mail-archive/web/tls/current/msg07564.html
Reference: URL: http://www.ietf.org/mail-archive/web/tls/current/msg07567.html
Reference: URL: http://www.ietf.org/mail-archive/web/tls/current/msg07553.html
Reference: URL: http://www.ietf.org/mail-archive/web/tls/current/msg07576.html
Reference: URL: http://www.ietf.org/mail-archive/web/tls/current/msg07577.html
Reference: MISC: http://orchilles.com/2011/03/ssl-renegotiation-dos.html
Reference: MISC: http://vincent.bernat.im/en/blog/2011-ssl-dos-mitigation.html
Reference: MISC: http://www.educatedguesswork.org/2011/10/ssltls_and_computational_dos.html
Reference: MISC: https://bugzilla.redhat.com/show_bug.cgi?id=707065

** DISPUTED ** Mozilla Network Security Services (NSS) 3.x, with
certain settings of the SSL_ENABLE_RENEGOTIATION option, does not
properly restrict client-initiated renegotiation within the SSL and
TLS protocols, which might make it easier for remote attackers to
cause a denial of service (CPU consumption) by performing many
renegotiations within a single connection, a different vulnerability
than CVE-2011-1473.  NOTE: it can also be argued that it is the
responsibility of server deployments, not a security library, to
prevent or limit renegotiation when it is inappropriate within a
specific environment.

NOTE: this was originally tracked in bug #707065.

Comment 1 Tomas Hoger 2012-08-07 10:01:12 UTC

As noted in bug 707065, comment 2, applications using NSS can easily instruct the library to refuse any SSL/TLS session renegotiation if such functionality is not needed using the SSL_ENABLE_RENEGOTIATION option value SSL_RENEGOTIATE_NEVER.

Setting NSS_SSL_ENABLE_RENEGOTIATION environment variable to value of 0 or n should mitigate this issue without modifying application, unless the application explicitly sets the SSL_ENABLE_RENEGOTIATION option.

I filed upstream bug as there was none yet.  It's quite likely upstream will decide to wontfix given the nature of this issue and available mitigation.

https://bugzilla.mozilla.org/show_bug.cgi?id=780846

Comment 3 Product Security DevOps Team 2021-06-11 21:04:34 UTC

This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2011-5094