[Snort-users] "stream.c" in Nessus causes tons of same alerts!

Xu Zhenqing xuzq at ...452...
Fri Sep 29 05:44:04 EDT 2000


snort-users:

 I start the Snort-1.7Beta0 with Mysql support
in my linux box. Everything is ok before I use
the Nessus Scanner against the target host.
After the scan, there are about 40,000 same 
items of "NMAP TCP PING!". The huge alert data
cause MySql works very slowly.

I look into the detail of the alert log, find that
src_ip = dst_ip! After the investigation, nessus 
simulates the "stream.c" attack in 
plugins/scripts/stream.nasl. This plugin sends about
40,000 IP packets with the src_ip = dst_ip = target host.

I think this is the cause of the tons of same alerts.
Change the first line of the scan-lib:
alert tcp any any -> $HOME_NET any (flag:A; ack:0; msg:"NMAP TCP PING!")
to :
alert tcp !$HOME_NET any -> $HOME_NET any (flag:A; ack:0; msg:"NAMP TCP PING!")

can avoid the tons of same alerts.

But now we will let the DOS attacker pass our SNORT. 

            Xu Zhenqing
            xuzq at ...452...




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