Bug 1970201 (CVE-2021-3601)

Summary:	CVE-2021-3601 openssl: Certificate with CA:FALSE is accepted as valid CA cert
Product:	[Other] Security Response	Reporter:	Huzaifa S. Sidhpurwala <huzaifas>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	crypto-team, hkario, mjc, mturk, sahana, security-response-team, tm
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:	A flaw was found in the way OpenSSL will accept a certificate with explicitly set Basic Constraints to CA:FALSE as a valid CA if it is present in the trusted bundle. This flaw allows an attacker with access to a private key, of which the corresponding certificate is in the trust bundle, to use this flaw for MITM to any connection from the victim machine.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-06-15 15:04:25 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:	1950376, 1971525

Description Huzaifa S. Sidhpurwala 2021-06-10 05:00:34 UTC

OpenSSL 1.0.2 will accept a certificate with explicitly set Basic Constraints to CA:FALSE as a valid CA if it is present in the trusted bundle.

Upstream bug: https://github.com/openssl/openssl/issues/5236

The exploitability of this bug is limited; the attacker needs to get access to a private key of which the corresponding certificate is in the trust bundle; but if, as an administrator, I want my machine to trust a specific self-signed certificate, that's precisely what I need to do. Then the attacker is able to leverage this certificate to MITM any connection from my machine, not just ones to the specific server that uses the self-signed certificate.

Comment 3 Product Security DevOps Team 2021-06-15 15:04:25 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-2021-3601