RE: Windows Remote Desktop

From: Depp, Dennis M. (deppdm_at_ornl.gov)
Date: 01/16/04

  • Next message: Shawn Jackson: "RE: A different question RE: Windows Remote Desktop" 
    Date: Fri, 16 Jan 2004 08:45:07 -0500
To: jamie@nucdc.org, security-basics@securityfocus.com

    The RDP protocol must setup the RD4 encryption. The first packet must
    be sent in plain text because the two machines have not yet agreed on
    how to encrypt the data. You will notice the mstshash= before
    administrator. This is what RDP is using to setup the encryption. I
    assume mstshash stands for MicroSoft Terminal Server HASH.

    Denny

    -----Original Message-----
    From: Jamie Pratt [mailto:jamie@nucdc.org]
    Sent: Thursday, January 15, 2004 4:31 PM
    To: security-basics@securityfocus.com
    Subject: Re: Windows Remote Desktop

    hmm... the 'main' traffic does appear encrypted, but this third packet
    sent on the initial RDP connection prior to login is somewhat odd: (the
    RDP session has 'Administrator' as the default account on the TS login
    screen, and I am running as Administrator myself - what's up with the
    username showing in the data section of the packet if it's all encrypted
    then?) - Well..at least I can't see the password going over the wire!

    ---------------------------------------------------------------------
    Frame 20 (94 bytes on wire, 94 bytes captured)
    Ethernet II, Src: 00:07:f4:ed:e4:af, Dst: 00:0f:43:71:2c:6e
    Internet Protocol, Src Addr: 192.168.X.X (192.168.X.X), Dst Addr:
    X.X.X.X (X.X.X.X)
    Transmission Control Protocol, Src Port: 1054 (1054), Dst Port: 3389
    (3389), Seq: 1, Ack: 1, Len: 40
    Source port: 1054 (1054)
    Destination port: 3389 (3389)
    Sequence number: 1
    Next sequence number: 41
    Acknowledgement number: 1
    Header length: 20 bytes
    Flags: 0x0018 (PSH, ACK)
    Window size: 16560
    Checksum: 0x25c9 (correct)

    Data (40 bytes)

    0000 03 00 00 28 23 e0 00 00 00 00 00 43 6f 6f 6b 69 ...(#......Cooki
    0010 65 3a 20 6d 73 74 73 68 61 73 68 3d 41 64 6d 69 e: mstshash=Admi
    0020 6e 69 73 74 72 61 0d 0a nistra..

    ------------------------------------------------------------------------

    regards,
    jamie

    Depp, Dennis M. wrote:
    > Two statements I don't agree with:
    >
    > 1) "Additionally no actual 'data' is transferred through the RDP
    > connection, it's just interface information (mouse movement, button
    > clicks, typing) and screen refreshes. Now if you were using the
    resource
    > mapping then data would traverse the RDP connection and would be
    subject
    > to its encryption."
    > Data is sent over the wire concerning keystrokes, mouse
    > movements and screen refresh data. Obviously this information,
    > particularly keystrokes can provide data to a hacker. However all
    > information set via RDP is encrypted the default is 56-bit with the
    > capacity to use 128-bit RC4. Even when using local resources, the
    data
    > is still encrypted with 128-bit security.
    >
    > 2) "All in all I think that PCAnywhere and Citrix have
    > more secure RDP/VNC like interfaces"
    > The default security setting in Citrix is basic (no encryption)
    > PCAnywhere maybe better, I'm not sure. Both Citrix and RDP are
    > vulnerable to MiM attacks. Citrix does have the capability to use
    SSL
    > but this is comprable to Microsoft's VPN solution.
    >
    > Denny
    >
    > -----Original Message-----
    > From: Shawn Jackson [mailto:sjackson@horizonusa.com]
    > Sent: Wednesday, January 14, 2004 6:36 PM
    > To: jamesworld@intelligencia.com
    > Cc: Michael Gale; security-basics@securityfocus.com
    > Subject: RE: Windows Remote Desktop
    >
    <snip>

    ------------------------------------------------------------------------ 

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