Bug 2003191 (CVE-2021-22947)

Summary:	CVE-2021-22947 curl: Server responses received before STARTTLS processed after TLS handshake
Product:	[Other] Security Response	Reporter:	Marian Rehak <mrehak>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	amctagga, andrew.slice, anharris, bdettelb, bniver, bodavis, caswilli, csutherl, dbhole, fjansen, flucifre, gkamathe, gmeno, gzaronik, hhorak, hvyas, jclere, jnakfour, jorton, jreznik, jwong, jwon, kanderso, kaycoth, kdudka, krathod, luhliari, lvaleeva, mbenjamin, mhackett, msekleta, mthacker, mturk, omajid, paul, pjindal, psegedy, rwagner, security-response-team, sostapov, svashisht, szappis, vereddy, vkumar, vmugicag
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	curl 7.79.0	Doc Type:	If docs needed, set a value
Doc Text:	A flaw was found in curl. The flaw lies in how curl handles cached or pipelined responses that it receives from either a IMAP, POP3, SMTP or FTP server before the TLS upgrade using STARTTLS. In such a scenario curl even after upgrading to TLS would trust these cached responses treating them as valid and authenticated and use them. An attacker could potentially use this flaw to carry out a Man-In-The-Middle attack. The highest threat from this vulnerability is to data confidentiality.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-11-02 14:08:24 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:	2003686, 2003687, 2003688, 2003689, 2003690, 2003733, 2003734, 2003735, 2003736, 2004363, 2004650, 2038280
Bug Blocks:	2001529

Description Marian Rehak 2021-09-10 14:39:26 UTC

When curl connects to an IMAP, POP3, SMTP or FTP server to exchange data securely using STARTTLS to upgrade the connection to TLS level, the server can still respond and send back multiple responses before the TLS upgrade. Using this flaw, it allows a Man-In-The-Middle attacker to first inject the
fake responses, then pass-through the TLS traffic from the legitimate server and trick curl into sending data back to the user thinking the attacker's injected data comes from the TLS-protected server.

Upstream Advisory:

https://github.com/curl/curl/commit/ec3bb8f727405

Comment 4 gkamathe 2021-09-15 06:35:20 UTC

Created curl tracking bugs for this issue:

Affects: fedora-all [bug 2004363]

Comment 6 Tomas Hoger 2021-10-07 09:04:03 UTC

Upstream advisory:

https://curl.se/docs/CVE-2021-22947.html

Comment 7 errata-xmlrpc 2021-11-02 08:43:50 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2021:4059 https://access.redhat.com/errata/RHSA-2021:4059

Comment 8 Product Security DevOps Team 2021-11-02 14:08:24 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-2021-22947

Comment 16 errata-xmlrpc 2022-02-22 15:54:31 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.2 Extended Update Support

Via RHSA-2022:0635 https://access.redhat.com/errata/RHSA-2022:0635

Comment 17 errata-xmlrpc 2022-04-13 14:29:21 UTC

This issue has been addressed in the following products:

  .NET Core on Red Hat Enterprise Linux

Via RHSA-2022:1354 https://access.redhat.com/errata/RHSA-2022:1354