1 icmp vulnerability, 2 illegal commands (netbios and smtp), Figure 51 smurf attack – ZyXEL Communications G.SHDSL.bis 4-port Security Gateway P-793H User Manual
Page 124
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P-793H User’s Guide
124
Chapter 8 Firewalls
Figure 51 Smurf Attack
8.4.2.1 ICMP Vulnerability
ICMP is an error-reporting protocol that works in concert with IP. The following ICMP types
trigger an alert:
8.4.2.2 Illegal Commands (NetBIOS and SMTP)
The only legal NetBIOS commands are the following - all others are illegal.
All SMTP commands are illegal except for those displayed in the following tables.
Table 35 ICMP Commands That Trigger Alerts
5
REDIRECT
13
TIMESTAMP_REQUEST
14
TIMESTAMP_REPLY
17
ADDRESS_MASK_REQUEST
18
ADDRESS_MASK_REPLY
Table 36 Legal NetBIOS Commands
MESSAGE:
REQUEST:
POSITIVE:
VE:
RETARGET:
KEEPALIVE:
Table 37 Legal SMTP Commands
AUTH
DATA
EHLO
ETRN
EXPN
HELO
HELP
NOOP
QUIT
RCPT
RSET
SAML
SEND
SOML
TURN
VRFY
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