[VulnWatch] Re: [LSD] Critical security vulnerability in Microsoft Operating Systems

From: Last Stage of Delirium (contact@lsd-pl.net)
Date: Tue Jul 22 2003 - 13:15:12 PDT

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    Hello,
    
    We confirm the existance of the following RPC attack vectors pointed out
    by Todd Sabin with regard to the vulnerability described in MS03-026.
    These are respectively:
    
    - ncacn_np:\pipe\epmapper
    - ncadg_ip_udp:135
    - ncacn_ip_tcp:135
    - ncacn_http:593
    
    This means that at least:
    - UDP port 135,
    - TCP ports 135, 139, 445 and 593 can be used as remote attack vectors.
    
    The possibility of using ncacn_http (and TCP port 80) for the purpose
    of launching a remote attack depends on whether COM Internet Services
    are enabled for DCOM on a Windows Server running IIS (as far as we know
    they are not enabled by default).
    
    Best Regards,
    Members of LSD Research Group
    http://lsd-pl.net
    
    
    On Thu, 17 Jul 2003, Todd Sabin wrote:
    
    >
    > I think it's worth mentioning that Microsoft's advisory on this issue
    > is incorrect in stating that the only attack vector is port 135.  The
    > vulnerability lies in one of the RPC interfaces that the endpoint
    > mapper/RPCSS services.  As such, it is accessible over any RPC
    > protocol sequence that the endpoint mapper listens on.  That includes:
    >
    > o ncacn_ip_tcp :  TCP port 135
    > o ncadg_ip_udp :  UDP port 135
    > o ncacn_np     :  \pipe\epmapper, normally accessible via SMB null
    >                   session on TCP ports 139 and 445
    > o ncacn_http   : if active, listening on TCP port 593.
    >
    > Finally, if ncacn_http is active, and COM Internet Services is
    > installed and enabled, which is NOT the default in any configuration
    > I'm aware of, then you can also talk to the endpoint mapper over port
    > 80.  Just to be clear, I think this is a very uncommon scenario, but
    > the possibility does exist.
    >
    > So if you want to be completely safe, block UDP 135, TCP 135, 139, 445,
    > and 593.  And make sure you don't have COM Internet Services running.
    >
    > --
    > Todd Sabin                                          <tsabinat_private>
    > BindView RAZOR Team                            <tsabinat_private>
    >
    



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