Re: Cisco 675 password nonsense

From: Francis Bodie (BFrancisat_private)
Date: Tue Aug 03 1999 - 08:24:39 PDT

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    This is all true, and shows one of the security
    issues with brining broadband access to the uneducated user.
    
    Since this is sort of related. I had to do a password recovery on a
    675,
    which is an undocumented procedure( or at least not in the manual.)
    
    To recover the password you do the following steps:
    
    1.  Reboot the Cisco 675
    
    2.  Access the device through the serial Console
    (Speed: 34000, 8, N,1)
    
    3.  Issue the break command, <CTRL>-C
    
    4.  The Cisco 675 should be display a prompt =>
    
    5.  Issue the command: ES 6   (Erase Page? 6)
    
    6.  Issue the command: M0     (Turn of monitor mode.)
    
    7.  Issue the command: go
    
    8.  The modem should reboot, with exec and ena passwords removed.
    
    *NOTE:  You will also loose your entire config.
    
    Apparently the whole ROM monitor mode on the 675 is
    a bit strange, most likely due to it being a former NetSpeed product.
    
    Bodie
    
    <DISCLAIMER>Views expressed here are not those of Space
    Imaging.</DISCLAIMER>
    
    > -----Original Message-----
    > From: DeMoNx [mailto:demonxat_private]
    > Sent: Saturday, July 31, 1999 2:58 PM
    > To: BUGTRAQat_private
    > Subject: Cisco 675 password nonsense
    >
    >
    > (First of all please forgive me if you dis-approve of my use
    > of the word
    > router. I just think it's a bot more appropriate term than
    > 'modem' for the
    > hardware being discussed.)
    >
    > Is your DSL router an open book???
    >
    > When a certain long distance provider/isp in my area began
    forcefully
    > switching all non-business/special adsl accounts over to
    > using PPP rather
    > than bridging mode for 'security reasons', I got a little
    > suspicious. With
    > bridging mode enabled on a Cisco 675, one used to be able to hook up
    > seemingly limitless machines (provided you have the hubs), to one
    dsl
    > connection using dhcp. Now with PPP, your dhcp server becomes
    > 10.10.10.0...your 675, which in turn uses dhcp or ipcp to handle
    > traffic between itself and your isp....blah blah blah etc.
    >
    > My point is, with all this wonderfully confusing hubub, many
    > people I'm
    > sure are pulling their hair out trying to fathom the first 5
    > pages of the
    > 'CBOS Users Guide', trying in vain to set up their dsl to
    > avoid paying $90
    > to the guys that will end up coming to their house and
    > setting it up for
    > them. The problem is, *most* of these guys don't set passwords on
    the
    > 675's. It is very simple to compromise an unpassworded 675. simply
    hit
    > 'enter' at the password prompt after telnetting in, if you get a
    cbos>
    > promt you are half way there, NOT GOOD. If there is no exec
    > mode password
    > set, then there most likely won't be an enable(superuser)
    > mode password
    > either. So, at this prompt you simply type 'enable' and hit
    > enter twice.
    > If you are in enable mode, your prompt will change to the #
    > symbol, and
    > you have full access to all the router's settings. ISP's are
    > letting this
    > happen, people are buying this technology without any
    > knowlege that they
    > may be at this kind of risk. Below is a log of one such Cisco 675.
    The
    > ip's and hostnames have been changed to protect the
    > irresponsible *and*
    > the uninformed.
    >
    > ---
    >
    >
    > $telnet adslppp93.lame.isp.net Trying 296.161.127.93...
    > Connected to adslppp93.lame.isp.net.
    > Escape character is '^]'.
    >
    > User Access Verification
    > Password:                  (Just hit enter, whoa! No password!)
    >
    > cbos>enable                (with just 8 keystrokes full
    > access is given)
    >
    > Password:
    >
    > cbos#stats ppp             (Hmm, who's 675 is this?)
    >
    > VC       VPI/VCI  STATE          MRU    USERNAME  RADIUS   TX
    RX
    > wan0-0   01/01   Opened State    2048   poorsap   disabled
    > 358673   358956
    >
    > cbos#exit
    > Connection closed by foreign host.
    >
    > now, to change these passwords (the easiest way of securing
    > the router)
    >
    > type 'enable' hit enter to enter administration mode
    >
    > then type 'set password exec clear NEWPASSWORD exec' to keep em out
    >
    > and then 'set password enable clear NEWPASSWORD enable' to change
    the
    > superuser password.
    >
    > This is what the person who setup the 675 *SHOULD* have done prior
    to
    > leaving the jobsite.
    >
    > Bill Watts
    >
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