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Custom signature syntax – Fortinet Network Device IPS User Manual

Page 24

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FortiGate IPS User Guide Version 3.0 MR7

24

01-30007-0080-20080916

Creating custom signatures

Custom signatures

Custom signature syntax

Table 2: Information keywords

Keyword and value

Description

--attack_id ; This optional value is used to identify the signature. It

cannot be the same value as any other custom rules within

the same VDOM. If an attack ID is not specified, the

FortiGate automatically assigns an attack ID to the

signature.
An attack ID you assign must be between 1000 and 9999.
Example:

--attack_id 1234;

--name ;

Enter the name of the rule. A rule name must be unique

within the same VDOM.
The name you assign must be a string greater than 0 and

less than 64 characters in length.
Example:

---name "Buffer_Overflow";

Table 3: Session keywords

Keyword and value

Description

--flow {from_client |
from_server |
bi_direction };

Specify the traffic direction and state to be inspected.

They can be used for all IP traffic.
Example:

--src_port 41523;

--flow bi_direction;

The signature checks traffic to and from port 41523.
Previous FortiOS versions used to_client and

to_server values. These are now deprecated, but

still function for backwards compatibility.

--service {HTTP | TELNET
| FTP | DNS | SMTP | POP3
| IMAP | SNMP | RADIUS |
LDAP | MSSQL | RPC | SIP
| H323 | NBSS | DCERPC |
SSH | SSL};

Specify the protocol type to be inspected.
This keyword allows you to specify the traffic type by

protocol rather than by port. If the decoder has the

capability to identify the protocol on any port, the

signature can be used to detect the attack no matter

what port the service is running on. Currently, HTTP,

SIP, SSL, and SSH protocols can be identified on any

port based on the content.