Well I happen to know the writer of "smurf.c" and he is really pissed at how his exploit for this attack has been passed around like candy, then again, he gave it out publically on the IRC. This bug is exactly like the one that "pepsi.c" exploited. Little kids will have their fun with it, realize that it is dumb and that people are patching themselves against it, and it will die. In the meantime , I did understand how it works, just explained it a little off :). Netstat Webmaster wrote:
On Wed, 30 Jul 1997, Systems Engineer wrote:
Actually people are making it seem that the entire MAE is sending you an echo. No one is mounting an attack from there, they are just making it look like it is coming from there.
Well thats not entirely true. In effect the victim is indeed being 'attacked' by MAE machines on that network. Look at it like this:
evil.com -> generates packet with forged address as (victim.com(icmp_echo)) -> destination for spoofed packet (25 .255 broadcast addresses).
From here... all 25 network's broadcast address pass the icmp with the forged address on to all machines using that network. Each machine then replies as:
xxx.xxx.xxx.255 abused.net.com (echo_reply) -> victim.com abused2.net.com (echo_reply) -> victim.com yyy.yyy.yyy.255 abused3.othernet.com (echo_reply) -> victim.com abused4.othernet.com (echo_reply) -> victim.com
[...etc...]
Its a rather obnoxious attack, and its not exactly new. Though I do think that it will get much worse now that smurf.c has been written and is being passed around like candy.
The real problem I see with this particular attack is that there is nothing short of blocking all ICMPs that 'victim.com' can do. At least
not that I am aware of.
Regards, Tripp
webmaster@http://www.netstat.net
-- --- --- --- --- --- --- --- --- --- Steven Nash ph: (516)248-8400ext25 Systems Engineer / Network Security fax: (516)248-8897 Lightning Internet Services LLC email: snash@lightning.net http://www.lightning.net --- --- --- --- --- --- --- --- ---