Bug 2056955 (CVE-2021-25636)

Summary:	CVE-2021-25636 libreoffice: Incorrect trust validation of signature with ambiguous KeyInfo children
Product:	[Other] Security Response	Reporter:	Sandipan Roy <saroy>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	caolanm, dtardon, erack, sbergman
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	libreoffice 7.2.5, libreoffice 7.3.0	Doc Type:	If docs needed, set a value
Doc Text:	A improper certificate validation flaw was found in LibreOffice allowing an attacker to manipulate a digitally signed ODF document to appear that no alteration of the document occurred since the last signing and that the signature is valid.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2022-12-04 01:03:15 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:	2056956, 2060559, 2060560, 2060561
Bug Blocks:	2056958

Description Sandipan Roy 2022-02-22 12:34:49 UTC

CVE-2021-25636

Title: Incorrect trust validation of signature with ambiguous KeyInfo children

Announced: February 22, 2022

Fixed in: LibreOffice 7.2.5/7.3.0

Description:

LibreOffice supports digital signatures of ODF documents and macros within documents, presenting visual aids that no alteration of the document occurred since the last signing and that the signature is valid.

An Improper Certificate Validation vulnerability in LibreOffice allowed an attacker to create a digitally signed ODF document, by manipulating the documentsignatures.xml or macrosignatures.xml stream within the document to contain both "X509Data" and "KeyValue" children of the "KeyInfo" tag[1], which when opened caused LibreOffice to verify using the "KeyValue" but to report verification with the unrelated "X509Data" value.

In versions >= 7.2.5 (and >= 7.3.0) certificate validation is configured to only consider X509Data children to limit validation to X509 certificates only.

[1] https://www.w3.org/TR/xmldsig-core1/#sec-KeyInfo

Comment 1 Sandipan Roy 2022-02-22 12:35:15 UTC

Created libreoffice tracking bugs for this issue:

Affects: fedora-all [bug 2056956]

Comment 2 Guilherme de Almeida Suckevicz 2022-03-03 18:06:30 UTC

Upstream patches:

https://gerrit.libreoffice.org/c/core/+/127193
https://gerrit.libreoffice.org/c/core/+/127179
https://gerrit.libreoffice.org/c/core/+/127178
https://gerrit.libreoffice.org/c/core/+/127177

Comment 5 errata-xmlrpc 2022-11-08 09:12:19 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2022:7461 https://access.redhat.com/errata/RHSA-2022:7461

Comment 6 Product Security DevOps Team 2022-12-04 01:03:13 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-2021-25636