Bug 1902011 (CVE-2020-27818)

Summary:	CVE-2020-27818 pngcheck: global buffer overflow was discovered in check_chunk_name function via crafted pngfile
Product:	[Other] Security Response	Reporter:	Marian Rehak <mrehak>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED UPSTREAM	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	code
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 check_chunk_name() function of pngcheck. This flaw allows an attacker who can pass a malicious file to be processed by pngcheck to cause a temporary denial of service. The highest threat from this vulnerability is to system availability.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-11-26 17:33:53 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:	1902012
Bug Blocks:	1902014

Description Marian Rehak 2020-11-26 15:16:37 UTC

A global buffer overflow was discovered in check_chunk_name function in pngcheck-2.4.0 via a crafted png file.

Reference:

https://bugzilla.redhat.com/show_bug.cgi?id=1897485

Comment 1 Marian Rehak 2020-11-26 15:17:03 UTC

Created pngcheck tracking bugs for this issue:

Affects: fedora-all [bug 1902012]

Comment 2 Product Security DevOps Team 2020-11-26 17:33:53 UTC

This CVE Bugzilla entry is for community support informational purposes only as it does not affect a package in a commercially supported Red Hat product. Refer to the dependent bugs for status of those individual community products.

Comment 4 Todd Cullum 2020-11-30 19:01:28 UTC

Flaw summary:

When pngcheck is provided a crafted input file, it could cause a global-buffer-overflow -> out-of-bounds read, due to improper use of casts in the check_chunk_name() function of pngcheck-2.4.0/pngcheck.c. Red Hat Product Security has designated this as a Low severity issue because an attacker would likely need to social engineer a user or already have access to a victim system, and exploiting this flaw would likely only lead to temporary denial of service (application crash).

Comment 5 Todd Cullum 2020-11-30 19:03:19 UTC

Mitigation:

To mitigate this flaw, do not provide input files from untrusted sources to pngcheck.

Comment 7 Todd Cullum 2020-12-02 19:50:40 UTC

External References:

F34/Rawhide: https://bodhi.fedoraproject.org/updates/FEDORA-2020-04d5e1ce26
F33:         https://bodhi.fedoraproject.org/updates/FEDORA-2020-4349e95c4f
F32:         https://bodhi.fedoraproject.org/updates/FEDORA-2020-23432b7b72
F31:         https://bodhi.fedoraproject.org/updates/FEDORA-2020-27b168926a
EPEL8:       https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2020-6c93c61069
EPEL7:       https://bodhi.fedoraproject.org/updates/FEDORA-EPEL-2020-339db397ad