Bug 1844161 (CVE-2020-11085)

Summary:	CVE-2020-11085 freerdp: out-of-bounds read in cliprdr_read_format_list function
Product:	[Other] Security Response	Reporter:	Guilherme de Almeida Suckevicz <gsuckevi>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	mads, negativo17, oholy, pahan
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	freerdp 2.1.0	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2020-09-29 22:01:34 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:	1844162, 1844163, 1844164, 1844165, 1844282, 1844283
Bug Blocks:	1844196

Description Guilherme de Almeida Suckevicz 2020-06-04 18:11:15 UTC

In FreeRDP before 2.1.0, there is an out-of-bounds read in cliprdr_read_format_list. Clipboard format data read (by client or server) might read data out-of-bounds. This has been fixed in 2.1.0.

Reference:
https://github.com/FreeRDP/FreeRDP/security/advisories/GHSA-2j4w-v45m-95hf

Upstream commit:
https://github.com/FreeRDP/FreeRDP/commit/b73143cf7ee5fe4cdabcbf56908aa15d8a883821

Comment 1 Guilherme de Almeida Suckevicz 2020-06-04 18:11:41 UTC

Created freerdp tracking bugs for this issue:

Affects: epel-6 [bug 1844164]
Affects: fedora-all [bug 1844163]


Created freerdp1.2 tracking bugs for this issue:

Affects: epel-7 [bug 1844165]
Affects: fedora-all [bug 1844162]

Comment 2 Todd Cullum 2020-06-05 00:20:28 UTC

Note that the flaw in the files reported for this CVE does not exist in any Red Hat Enterprise Linux version. However, the flaw exists instead in cliprdr_process_format_list() in client/cliprdr_main.c and cliprdr_server_receive_format_list() in server/cliprdr_main.c for FreeRDP-2.0.0-rc4. This version is shipped in Red Hat Enterprise Linux 8 and Red Hat Enterprise Linux 7. freerdp 1.0.2, as shipped in Red Hat Enterprise Linux 6 is significantly different and this flaw does not appear to exist there. The issue is that the code:

		while (dataLen)
		{
			Stream_Read_UINT32(s, formats[index].formatId); /* formatId (4 bytes) */
			dataLen -= 4;

			formats[index].formatName = NULL;

if dataLen is less than 4, an out-of-bounds read is possible.

Comment 4 Todd Cullum 2020-06-05 00:38:33 UTC

Mitigation:

To mitigate this flaw in vulnerable versions, clipboard support should be disabled for freerdp sessions.

Comment 5 errata-xmlrpc 2020-09-29 20:43:58 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2020:4031 https://access.redhat.com/errata/RHSA-2020:4031

Comment 6 Product Security DevOps Team 2020-09-29 22:01:34 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-2020-11085

Comment 7 errata-xmlrpc 2020-11-04 02:39:01 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2020:4647 https://access.redhat.com/errata/RHSA-2020:4647