By slipstream/RoL.

Overview

PC Matic "provides superior security protection over all security products, free or otherwise, on the market".

An issue in PC Matic, versions 1.1.0.65 and below, can be exploited by an entity in a man-in-the-middle position to cause remote code execution, as SYSTEM or as a standard user.

Issues in PC Matic, versions 1.1.0.65 and below, can be exploited by a web page to potentially cause remote code execution as a standard user.

Issues

The PC Matic application is basically Internet Explorer. A version of IE that allows for certain objects like WScript.Shell to be instantiated. The application loads a home page via HTTP, which then loads some javascript files, which among other things do call out to WScript.Shell. An entity in a MITM position can easily intercept requests to http://*.pcpitstop.com/Nirvana/*.js and respond with JavaScript of their choice, the traditional calc.exe payload here being:

(new ActiveXObject('WScript.Shell')).Run('calc.exe');

Additionally, the PC Matic installer installs a service that runs as SYSTEM, which essentially runs wscript scan.wsf every hour, as SYSTEM. scan.wsf basically GETS the contents of http://www.pcpitstop.com/Nirvana/scheduledscanpack.js and then eval()s it. So an entity in a MITM position can just wait up to an hour for the service to run their own JavaScript, as SYSTEM.

PC Matic also installs and uses several ActiveX controls, that are signed by a code signing certificate issued by Thawte. One of these ActiveX controls, PCPitstop2.dll, exposes some interesting methods to IE. Some are limited to specific domains (however, any cross-site-scripting issue in the allowed domains would bypass this limitation). Some, however, are not; and so...

<object name="Exam" id="Exam" classid="CLSID:FFB3A759-98B1-446F-BDA9-909C6EB18CC7"></object>
<script>
    (function(){
        var e = document.getElementById('Exam');
        e.DeviceDriverInstallArguments = "-EncodedCommand ...";
        e.InstallDriver("powershell.exe","","");
    })();
</script>

... would happily execute powershell.exe -EncodedCommand ... with user permissions, assuming the user clicked Allow on the Protected Mode security warning. And, let's face it: PC Matic shows advertisements on Fox News; these would probably be the kind of users who'd just allow all the things. Not to mention they'd be the kind of users who still use IE, too.

Affected Versions

1.1.0.65 and below.

Solution

Uninstallation of this software will prevent exploitation of these issues. The researchers cannot sanction any mitigations except to remove this software definitively from any affected devices.