Vulnerability Development mailing list archives
Re: swbell DSL bug ?
From: vassago999 () HOTMAIL COM (vassago)
Date: Mon, 8 May 2000 18:04:21 -0500
You do not actually have to change the MAC address of the card. You could very easily custom build dhcp requests, with any MAC address specified within the dhcp packet, without ever altering the address on the card. I coded a pretty simple app in VB that does just that. It wouldn't be much trouble to query other machines for their MAC address, and then use those addresses to lease IP addresses. Since the dhcp server would reserve those IP's to the spoofed MAC addresses of legitimate customers, they probably wouldn't realize there was a problem for a while, unless they sniffed the traffic. ----- Original Message ----- From: J . Phillips <jamie.phillips () NS SYMPATICO CA> To: <VULN-DEV () SECURITYFOCUS COM> Sent: Monday, May 08, 2000 7:36 AM Subject: Re: swbell DSL bug ?
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Absolutley, my DSL provider's DHCP will only assign an IP to the MAC address on the NIC they provided, and it is always the same internal IP. There are however ways to change the burned in address, with which you could theoretically borrow someone else's IP on the same subnet, provided they did not have an IP already leased.(or perhaps even if they do??.) Jamie - -----Original Message----- From: VULN-DEV List [mailto:VULN-DEV () SECURITYFOCUS COM]On Behalf Of Seth R Arnold Sent: May 7, 2000 9:57 PM To: VULN-DEV () SECURITYFOCUS COM Subject: Re: swbell DSL bug ? Ryan, that just means they don't keep good enough track of things -- dhcp servers can be configured to assign leases only for certain MACs. * Ryan Sweat <batrox () SWBELL NET> [000507 17:13]:Southwester Bell is a big provider of dsl access in some parts of the US. Dhcp provides an IP address and the lease expires in about 72 hours. They claim the IP cannot be changed, however when playing around last night, I found if you install another ethernet card, and switch the cable to the new card, it happily gives you another IP address. The dhcp server must rely on mac address when providing a lease for an ip. This could pose many problems. How can accounting be kept when a user can change his ip whenever he likes? I have more testing to do, but I do not see why you couldnt install a few nic cards and get ip address for each one, which swbell would like to charge you much more money for. I am looking into a way to change the mac address in windows. I know it can be done in linux through ifconfig. Maybe somone has experience in this ?? batrox () swbell net- -- Seth Arnold | http://www.willamette.edu/~sarnold/ Hate spam? See http://maps.vix.com/rbl/ for help 'Netscape engineers are weenies!' -- Microsoft -----BEGIN PGP SIGNATURE----- Version: PGPfreeware 6.5.2 for non-commercial use <http://www.pgp.com> iQA/AwUBORa03tGSUCkLAscrEQIQMACfU6bo3nrovauUJQZhGN1ng/wcndgAn0+9 587Xyuwz7Zn7TvnJAotgyL4s =+yJR -----END PGP SIGNATURE-----
Current thread:
- Re: The Million Dollar Solution, (continued)
- Re: The Million Dollar Solution Joerg Mayer (May 06)
- Re: The Million Dollar Solution Jeremy Speer (May 06)
- Re: The Million Dollar Solution Richard Rager (May 07)
- Re: The Million Dollar Solution Joerg Mayer (May 06)
- Re: The Million Dollar Solution Alexander Sanda (May 06)
- Re: The Million Dollar Solution Dimitry Andric (May 06)
- Re: The Million Dollar Solution Vince Gittins (May 06)
- Re: The Million Dollar Solution Oystein Viggen (May 07)
- swbell DSL bug ? Ryan Sweat (May 07)
- Re: swbell DSL bug ? Seth R Arnold (May 07)
- Re: swbell DSL bug ? J . Phillips (May 08)
- Re: swbell DSL bug ? vassago (May 08)
- swbell DSL bug ? Ryan Sweat (May 07)
- Re: swbell DSL bug ? Ryan Bonnett (May 07)
- Re: swbell DSL bug ? spoonm (May 08)
- Re: swbell DSL bug ? marc (May 08)