Bug 1887319 (CVE-2020-25648)

Summary:	CVE-2020-25648 nss: TLS 1.3 CCS flood remote DoS Attack
Product:	[Other] Security Response	Reporter:	Huzaifa S. Sidhpurwala <huzaifas>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	crypto-team, dbasant, dueno, elio.maldonado.batiz, kai-engert-fedora, kdudka, nss-nspr-maint, rrelyea, security-response-team, yozone
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	nss 3.58	Doc Type:	If docs needed, set a value
Doc Text:	A flaw was found in the way NSS handled CCS (ChangeCipherSpec) messages in TLS 1.3. This flaw allows a remote attacker to send multiple CCS messages, causing a denial of service for servers compiled with the NSS library. The highest threat from this vulnerability is to system availability.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-04-27 16:46:30 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:	1887720, 1887721, 1889579, 1976249
Bug Blocks:	1887320

Description Huzaifa S. Sidhpurwala 2020-10-12 06:14:32 UTC

NSS allows an attacker to send CCS messages in a row after ClientHello message. If an attacker put multiple CCS messages in a single tcp packet, the NSS server will stuck in a loop for many times to process the messages. 

This issue affects servers which are compiled against the NSS library. Other consumers of NSS like firefox etc are not affected by this flaw.

Comment 2 Huzaifa S. Sidhpurwala 2020-10-13 08:04:31 UTC

Upstream patch: https://hg.mozilla.org/projects/nss/rev/57bbefa793232586d27cee83e74411171e128361
Upstream bug (currently private): https://bugzilla.mozilla.org/show_bug.cgi?id=1641480

Comment 4 RaTasha Tillery-Smith 2020-10-15 19:23:58 UTC

Statement:

This flaw only affects servers that are compiled with the NSS library and when the TLS 1.3 protocol is used.

Comment 5 Huzaifa S. Sidhpurwala 2020-10-20 04:00:25 UTC

External References:

https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/NSS_3.58_release_notes

Comment 6 Huzaifa S. Sidhpurwala 2020-10-20 04:02:07 UTC

Acknowledgments:

Name: the Mozilla project

Comment 7 Bob Relyea 2021-02-18 22:59:16 UTC

Wrong bug.

Comment 8 Divya 2021-03-01 05:29:41 UTC

Hello 

Can we have status update on this CVE for RHEL platforms marked affected as per https://access.redhat.com/security/cve/cve-2020-25648. I notice that for fedora, it has already been marked fixed at https://bugzilla.redhat.com/show_bug.cgi?id=1889579

Regards, 
Divya

Comment 10 errata-xmlrpc 2021-04-27 11:30:38 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2021:1384 https://access.redhat.com/errata/RHSA-2021:1384

Comment 11 Product Security DevOps Team 2021-04-27 16:46:30 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-2020-25648

Comment 12 errata-xmlrpc 2021-09-21 08:38:24 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2021:3572 https://access.redhat.com/errata/RHSA-2021:3572