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Thread: better quality with VNC payloads?

  1. #1
    Senior Member BigMac's Avatar
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    Default better quality with VNC payloads?

    This has been something thats bothered me in the past, are there any options with the metasploit multi/hanlder for getting better quality during a vnc session?

    its like the remote side of the vncviewer is set by default to view 1 frame per second!

    any ideas? any one experience this?

  2. #2
    Member imported_vvpalin's Avatar
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    Can i ask why you would want to use vnc in the first place ??
    Using backtrack for the first time is like being 10 years old again with the keys to a Ferrari.

  3. #3
    Senior Member BigMac's Avatar
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    Quote Originally Posted by vvpalin View Post
    Can i ask why you would want to use vnc in the first place ??
    i make video tutorials sometimes, im never able to use a vnc payload during a screen capture because of the low fps...

  4. #4
    Super Moderator lupin's Avatar
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    Quote Originally Posted by BigMac View Post
    This has been something thats bothered me in the past, are there any options with the metasploit multi/hanlder for getting better quality during a vnc session?

    its like the remote side of the vncviewer is set by default to view 1 frame per second!

    any ideas? any one experience this?
    Ive experienced it, and the universal opinion I have heard on the issue is that "slow" or "not working at all" is the normal mode of operation for the vlc payload.

    If you do get it working well it would probably be worthwhile sharing your method on the forums because it seems it's a common problem. Personally I don't bother to use it, preferring a regular shell or a meterpreter session.
    Capitalisation is important. It's the difference between "Helping your brother Jack off a horse" and "Helping your brother jack off a horse".

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  5. #5
    Senior Member BigMac's Avatar
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    Quote Originally Posted by lupin View Post
    Ive experienced it, and the universal opinion I have heard on the issue is that "slow" or "not working at all" is the normal mode of operation for the vlc payload.

    If you do get it working well it would probably be worthwhile sharing your method on the forums because it seems it's a common problem. Personally I don't bother to use it, preferring a regular shell or a meterpreter session.
    im sure its a simple tweek with how metasploit launches vncviewer.exe. . . if you read the comand line help of vncviewer.exe -h you will see the fps options but why would hdmoor or who ever choose to launch vncviewer with so little fps? i have been looking threw the source but have not found what im looking for... sometimes you just need that second pair of eyes ,-)

    i too would wrather use a shell or a meterpreter but sometimes you need that visual...

    just a tip! you have to put your mouse over the black vncscreen and shake the mouse to refre4sh the screen, you must do this everytime to see the next frame ,-(

  6. #6
    Very good friend of the forum Gitsnik's Avatar
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    Quote Originally Posted by BigMac View Post
    im sure its a simple tweek with how metasploit launches vncviewer.exe. . . if you read the comand line help of vncviewer.exe -h you will see the fps options but why would hdmoor or who ever choose to launch vncviewer with so little fps?
    I would imagine the server has something to do with it as well, considering I don't have any VNC libraries installed on my test machine at the moment and metasploit still does its thing just fine.

    In terms of frame rate, I note that I only get 16bit colour out of my XPSP3 test machine and that it seems responsive and handles fine. The fact that I have my router set up to treat that network as though it is 23 hops away (thus introducing a delay) probably helps this.

    So, speculation: Frame rate is so low because the payload is designed to be used across WAN links. Also coding a faster 32 bit image style is probably too annoying.

    Try setting up a different machine with a VNC listener ready to catch the session, then set that host as your exploit payload and try it from there - that way you can at least eliminate whether it is the payload or the server that is causing the frame rate issues - judging by how my machines reacted I'd say it's the server, but I've been wrong on more occasions than I care to remember.
    Still not underestimating the power...

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  7. #7
    Super Moderator lupin's Avatar
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    Quote Originally Posted by BigMac View Post
    i too would wrather use a shell or a meterpreter but sometimes you need that visual...
    Yeah, I guess its useful for demos, if not for serious work.

    Quote Originally Posted by BigMac View Post
    just a tip! you have to put your mouse over the black vncscreen and shake the mouse to refre4sh the screen, you must do this everytime to see the next frame ,-(
    Not exactly the most usable interface, is it?
    Capitalisation is important. It's the difference between "Helping your brother Jack off a horse" and "Helping your brother jack off a horse".

    The Forum Rules, Forum FAQ and the BackTrack Wiki... learn them, love them, live them.

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