Bug 1475224 (CVE-2017-2834)

Summary:	CVE-2017-2834 freerdp: Out-of-bounds write in license_recv()
Product:	[Other] Security Response	Reporter:	Adam Mariš <amaris>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	mads, negativo17, oholy, pahan, pokorra.mailinglists
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2017-08-07 13:58:58 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1475245, 1475246, 1475247
Bug Blocks:	1475243

Description Adam Mariš 2017-07-26 08:38:00 UTC

An exploitable code execution vulnerability exists in the authentication functionality of FreeRDP 2.0.0-beta1+android11. A specially crafted server response can cause an out-of-bounds write resulting in an exploitable condition. An attacker can compromise the server or use a man in the middle attack to trigger this vulnerability.

The vulnerability is located in the license server handling. The license message sent by the server contains a length field, which is not correctly verified by FreeRDP. For internal purposes, the library decreases this value by 4, if the server is sent a value inferior to 3, this will result in a negative value and the writing of packet contents outside of the allocated buffer in memory. This vulnerability can allow the execution of arbitrary code on the FreeRDP client side.

External References:

https://www.talosintelligence.com/vulnerability_reports/TALOS-2017-0336
http://blog.talosintelligence.com/2017/07/vulnerbility-spotlight-freerdp-multiple.html

Comment 1 Adam Mariš 2017-07-26 09:31:16 UTC

Created freerdp tracking bugs for this issue:

Affects: epel-6 [bug 1475247]
Affects: fedora-all [bug 1475246]


Created freerdp1.2 tracking bugs for this issue:

Affects: fedora-all [bug 1475245]

Comment 2 Stefan Cornelius 2017-07-27 14:27:57 UTC

Patch:
https://github.com/FreeRDP/FreeRDP/pull/4055/commits/8292b4558f0684065ce1f58db7783cc426099223

Comment 3 Stefan Cornelius 2017-08-07 13:59:06 UTC

Statement:

Red Hat Product Security has rated this issue as having Moderate security impact. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.