[bug] Cant do reverse connect via automated task (scheduler)

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[bug] Cant do reverse connect via automated task (scheduler)

Postby AnotherUVNCuser » 2017-10-01 01:23

Hello all (and Rudi) :-)


The following has been tested using 1.2.1.6, under a virtual Windows 7 Home Basic Edition (x86) and a real Windows 10 Pro (x64)


I wanted to execute a reverse connection to my own computer via an automated task (Windows Task Scheduler).
The task gets executed but nothing happens.

For your information:

The Task Scheduler does NOT execute WINVNC -connect HOSTNAME/IP directly,
but runs a self compiled commandline .exe, that i've made using http://orwelldevcpp.blogspot.be/ and http://www.codeblocks.org/

Code: Select all
#include <windows.h>
//#include <winver.h>

using namespace std;

int main() {

//   system("NETSTAT -N | FINDSTR /I ESTABLISHED | FINDSTR :1234 >NUL || winvnc.exe -connect 192.168.0.226:1234");
   system("winvnc.exe -connect 192.168.0.226");
   return 0;

}


With TightVNC this works fine, but with UltraVNC it doesn't do anything.

Hopefully this can be fixed, as i intent to run multiple commands on a scheduled/repeating time and want to do this via an .exe, so that i don't have to add more stuff to the task scheduler (i prefer this method over a .bat/.cmd).
With the automated task i can manage my computers when i'm not at home, without having to manually connect to them (call me lazy, i find it convenient :mrgreen:).

Also (to eliminate any misunderstandings): the server connects to the correct address, the 192. was purely entered as an example and i also use encryption/authentication.


EDIT: 1.2.1.7 is also affected

/AnotherUVNCuser
Last edited by AnotherUVNCuser on 2017-10-01 16:43, edited 6 times in total.
AnotherUVNCuser
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[bug] Cant do reverse connect via automated task (scheduler)

Postby AnotherUVNCuser » 2017-10-01 02:25

I have recorded a video in which i demonstrate the (reproducable) problem (1.2.1.7 is also affected):

https://www.youtube.com/watch?v=P4tpjXDbGX8
AnotherUVNCuser
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Posts: 31
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Re: [bug] Cant do reverse connect via automated task (schedu

Postby AnotherUVNCuser » 2017-10-02 15:45

The problem with the non running task really appears to be related to session 0 (SYSTEM) :/

Isn't it possible to make it compatible with the Windows SYSTEM account?

Besides trying the system(); C++ directive i've also tried the following (of which both methods fail when trying to run them from a SYSTEM task):

ShellExecute
Code: Select all
#include <windows.h>

// using namespace std;

int main()

{

   ShellExecute(0, "open", "winvnc.exe", "-connect 192.168.0.226:1234", 0, 1);

   return 0;

}



CreateProcess
Code: Select all
#include <windows.h>

// using namespace std;

int main()

{
   HWND            hWnd;
   STARTUPINFO         sInfo;
   PROCESS_INFORMATION   pInfo;

   ZeroMemory(&sInfo, sizeof(sInfo));
   sInfo.cb = sizeof(sInfo);
   ZeroMemory(&pInfo, sizeof(pInfo));

   char cmdArgs[] = " -connect 192.168.0.226:1234";

   if(CreateProcess("winvnc.exe", cmdArgs, NULL, NULL, false, 0, NULL, NULL, &sInfo, &pInfo));

    {
//        WaitForSingleObject(pInfo.hProcess,INFINITE);

        CloseHandle(pInfo.hThread);
        CloseHandle(pInfo.hProcess);

    } 

    return 0;

}


EDIT: After some more testing, i've came to a possible solution (i don't want to call it a workaround just yet).

I've noticed that i can make the task work when choosing a different built in account, i.e. SID: S-1-5-32-545, which is the built in users account.

(found here: https://support.microsoft.com/nl-nl/hel ... ng-systems )

Using this account, i only don't know if it can connect to me without me having to log on first (which would defeat its purpose of my usage goal).
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