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NSE4 · Question #504

You are creating a custom signature. Which has incorrect syntax?

The correct answer is A. F-SBID(--attack_id 1842,--name "Ping.Death";--protocol icmp; --data_size>32000;). The incorrect syntax in the custom signature is the use of a comma to separate parameters where a semicolon is required.

Submitted by jaden.t· Apr 18, 2026Security Profiles and Content Inspection

Question

You are creating a custom signature. Which has incorrect syntax?

Options

  • AF-SBID(--attack_id 1842,--name "Ping.Death";--protocol icmp; --data_size>32000;)
  • BF-SBID(--name "Block.SMTP.VRFY.CMD";--pattern "vrfy";-- service SMTP; --no_case;--
  • CF-SBID(--name "Ping.Death";--protocol icmp;--data_size>32000;)
  • DF-SBID(--name "Block".HTTP.POST"; --protocol tcp;-- service HTTP;-- flow from_client; --

How the community answered

(33 responses)
  • A
    76% (25)
  • B
    9% (3)
  • C
    3% (1)
  • D
    12% (4)

Why each option

The incorrect syntax in the custom signature is the use of a comma to separate parameters where a semicolon is required.

AF-SBID(--attack_id 1842,--name "Ping.Death";--protocol icmp; --data_size>32000;)Correct

FortiGate custom IPS signature definitions (F-SBID) require semicolons (`;`) to separate parameters within the signature definition, making the syntax `attack_id 1842,--name` incorrect due to the comma.

BF-SBID(--name "Block.SMTP.VRFY.CMD";--pattern "vrfy";-- service SMTP; --no_case;--

This syntax appears correct, with semicolons properly separating parameters like `--name`, `--pattern`, `--service`, and `--no_case`.

CF-SBID(--name "Ping.Death";--protocol icmp;--data_size>32000;)

This syntax appears correct, using semicolons to separate `--name`, `--protocol`, and `--data_size` parameters.

DF-SBID(--name "Block".HTTP.POST"; --protocol tcp;-- service HTTP;-- flow from_client; --

This syntax also appears correct, using semicolons to separate `--name`, `--protocol`, `--service`, and `--flow` parameters.

Concept tested: FortiGate custom signature syntax

Source: https://docs.fortinet.com/document/fortigate/7.4.0/handbook/115469/custom-ips-signatures

Topics

#Custom Signature#IPS#Syntax#Security Profile

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