Re: Faking logout with XTACACS

From: Eric Vyncke (evynckeat_private)
Date: Fri Dec 26 1997 - 04:47:14 PST

  • Next message: J.A. Gutierrez: "Re: Gzip & segmentation faults"

    More comments in-line...
    
    At 11:23 23/12/97 PST, Coaxial Karma wrote:
    >Hi,
    >
    >I dunno if what follows has already been posted or not... Sorry if it
    >has
    >been.
    >
    >I recently discovered that when a Terminal Server (TS) was using XTACACS
    >as authentication protocol, it was possible to make the XTACACS server
    >believes that you've disconnected.
    >
    >In order to exploit this, you only have to send an xlogout request to
    >the
    >XTACACS server claiming to be from the TS.  Here is an example:
    
    1) please note my affiliation to assert my bias ;-)
    
    2) you should really neither use the old TACACS nor XTACACS but rather
    RADIUS or TACACS+:
            - they are available in free source code in C
            - they protect/authenticate the packets by a shared secret
              between the Access Control Server and the Access Router/Firewall
              (Radius encrypts only the password so have less confidentiality
              that TACACS+ which encrypts almost everything)
            - Radius and TACACS+ are widely supported
    
    Best regards
    
    -eric
    
    Eric Vyncke
    Technical Consultant               Cisco Systems Belgium SA/NV
    Phone:  +32-2-778.4677             Fax:    +32-2-778.4300
    E-mail: evynckeat_private          Mobile: +32-75-312.458
    



    This archive was generated by hypermail 2b30 : Fri Apr 13 2001 - 13:37:35 PDT