Sequence of scans

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Sequence of scans

FortiWeb Cloud applies protection rules and performs scans according to orders in the table below (from the top to the bottom).

You may find that the actual scan sequence sometimes is different from that listed in the following scan sequence table. Various reasons may explain this, for example, for the scans involving the whole request or response packet, its sequence may vary depending on when the packet is fully transferred to FortiWeb Cloud. File Protection is one of the scan items that involve scanning the whole packet. FortiWeb Cloud scans Content-Type: and the body of the file for File Protection. While the Content-Type: is scanned instantly, the body of the file may be postponed after the subsequent scans until the whole body of the file is done uploading to FortiWeb Cloud.

Please also note that the scan sequence refers to the sequence within the same packet. For example, TCP Connection Number Limit precedes HTTP Request Limit in the scan sequence table. However, if there are two packets containing HTTP traffic and TCP traffic respectively, and the HTTP packet arrives first, FortiWeb Cloud thus checks the HTTP Connection Number Limit first.

To improve performance, block attackers using the earliest possible technique in the execution sequence and/or the least memory-consuming technique. The blocking style varies by feature and configuration. For example, when detecting Syntax-based SQL injection, instead of blocking the SQL injection by its syntax, you could log and block the injection by the blocklist defined in IP List. For details, see each specific feature.

Scan/action	Involves
TCP Connection Number Limit (TCP Flood Prevention)	Source IP address of the client in the IP layer. Source port of the client in the TCP layer.
Add X-Forwarded-For:	`X-Forwarded-For:` `X-Real-IP:` `X-Forwarded-Proto:`
IP List	Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the `SRC` field in the IP header, or the `X-Forwarded-For:` and `X-Real-IP:` HTTP headers. For details, see Rewriting Requests. Source IP address of the client in the IP layer. Note: If a source IP is in allowlist, subsequent checks will be skipped.
IP Reputation	Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the `SRC` field in the IP header, or the `X-Forwarded-For:` and `X-Real-IP:` HTTP headers. For details, see Rewriting Requests.
Geo IP	Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the `SRC` field in the IP header, or the `X-Forwarded-For:` and `X-Real-IP:` HTTP headers. For details, see Rewriting Requests. Source IP address of the client in the IP layer.
WebSocket security	`Host:` URL in HTTP header `Origin:` `Upgrade:` Frame Size/Message Size `sec-websocket-extenstions`
HTTP Allow Method	`Host:` URL in HTTP header `Request method in HTTP header`
HTTP Request Limit (HTTP Flood Prevention)	Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the `SRC` field in the IP header, or the `X-Forwarded-For:` and `X-Real-IP:` HTTP headers. For details, see Rewriting Requests. `Cookie:` Session state URL in the HTTP header HTTP request body
TCP Connection Number Limit (Malicious IP)	`Cookie:` Session state Source IP address of the client in the IP layer Source port of the client in the TCP layer
HTTP Request Limit (HTTP Access Limit)	`ID` field of the IP header Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the `SRC` field in the IP header, or the `X-Forwarded-For:` and `X-Real-IP:` HTTP headers. For details, see Rewriting Requests. . HTTP request body
URL Access	Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the `SRC` field in the IP header, or the `X-Forwarded-For:` and `X-Real-IP:` HTTP headers. For details, see Rewriting Requests. `Host:` URL in HTTP header Source IP of the client in the IP header
Mobile API Protection	`Host:` URL in HTTP header Token header
Protocol Limits	Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the `SRC` field in the IP header, or the `X-Forwarded-For:` and `X-Real-IP:` HTTP headers. For details, see Rewriting Requests. `Content-Length:` Parameter length Body length Header length Header line length Count of `Range:` header lines Count of cookies
File Protection	Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the `SRC` field in the IP header, or the `X-Forwarded-For:` and `X-Real-IP:` HTTP headers. For details, see Rewriting Requests. `Content-Type:` in `PUT` and `POST` requests URL in HTTP header The body of the file
Bot Deception	`Host:` URL in the HTTP header
Cross-site request forgery (CSRF) attacks	`<a href>` `<form>`
Protection for Man-in-the-Browser (MITB) attacks	`Host:` URL in HTTP header Request method in HTTP header Parameters in URL `Content-Type:`
Biometrics Based Detection	Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the `SRC` field in the IP header, or the `X-Forwarded-For:` and `X-Real-IP:` HTTP headers. For details, see Rewriting Requests. URL `Host:` `X-Forwarded-For:`
XML Protection	URL HTTP header Body
JSON Protection	URL HTTP header Body
Signature Based Detection	Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the `SRC` field in the IP header, or the `X-Forwarded-For:` and `X-Real-IP:` HTTP headers. For details, see Rewriting Requests. HTTP headers HTML Body URL in HTTP header Parameters in URL and request body
SQL Syntax Based Detection	`Host:` `Cookie:` URL in HTTP header Parameters in URL and request body
Custom Rule	Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the `SRC` field in the IP header, or the `X-Forwarded-For:` and `X-Real-IP:` HTTP headers. For details, see Rewriting Requests. URL in the HTTP header HTTP header Parameter in the URL
Threshold Based Detection	Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the `SRC` field in the IP header, or the `X-Forwarded-For:` and `X-Real-IP:` HTTP headers. For details, see Rewriting Requests. URL `Host:` `X-Forwarded-For:`
Account Takeover	`Host:` `Cookie:` Parameters in the URL URL in HTTP header HTTP body Client's certificate
API Gateway	`Host:` URL in HTTP header API Key as HTTP parameter in URL API Key as HTTP header Source IP address of the client depending on your configuration of API user Request methods in HTTP header HTTP Referer depending on your configuration of API user
OpenAPI Validation	`Host:` HTTP headers, especially the `content-type:` headers URL in HTTP header Request method in HTTP header Parameters in URL Multipart filename
URL Rewriting (rewriting & redirection)	`Host:` `Referer:` `Location:` URL in HTTP header HTML body
Machine Learning - Anomaly Detection	Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the `SRC` field in the IP header, or the `X-Forwarded-For:` and `X-Real-IP:` HTTP headers. For details, see "Defining your proxies, clients, & X-headers" on page 1. URL in the HTTP header Request method in HTTP header Parameter in the URL, or the HTTP header or body `Content-Type:`
Compression	`Accept-Encoding:`
Cookie Security	Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the `SRC` field in the IP header, or the `X-Forwarded-For:` and `X-Real-IP:` HTTP headers. For details, see Request Limits `Cookie:`
Reply from server to client
Web Socket Protocol	`Upgrade:`
Caching	`Host:` HTTP method Return code URL in the HTTP header `Content-Type:` HTTP headers Size in kilobytes (KB) of each URL to cache
Bot Deception	`Host:` URL in the HTTP header
Protection for Man-in-the-Browser (MiTB) attacks	Status code Response body
Biometrics Based Detection	Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the `SRC` field in the IP header, or the `X-Forwarded-For:` and `X-Real-IP:` HTTP headers. For details, see Request Limits URL `Host:` `X-Forwarded-For:` HTTP header Custom signature Body The latest HTTP transaction time The response content type Status code
Signature Based Detection (Information Leakage)	Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the `SRC` field in the IP header, or the `X-Forwarded-For:` and `X-Real-IP:` HTTP headers. For details, see Request Limits HTTP headers HTML Body URL in HTTP header Parameters in URL and body XML in the body of HTTP POST requests Cookies Headers JSON Protocol Detection Uploaded filename (MULTIPART_FORM_DATA_FILENAME)
Custom Rule	HTTP response code `Content-Type:`
Account Takeover	Status code HTTP headers HTML body
URL Rewriting (rewriting)	`Host:` `Referer:` `Location:` URL in HTTP header HTML body
HTTP Header Security	HTTP headers

Sequence of scans

FortiWeb Cloud applies protection rules and performs scans according to orders in the table below (from the top to the bottom).

Scan/action

Involves

TCP Connection Number Limit (TCP Flood Prevention)

Source IP address of the client in the IP layer.
Source port of the client in the TCP layer.

Add X-Forwarded-For:

X-Forwarded-For:
X-Real-IP:
X-Forwarded-Proto:

IP List

Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the SRC field in the IP header, or the X-Forwarded-For: and X-Real-IP: HTTP headers.
For details, see Rewriting Requests.
Source IP address of the client in the IP layer.

Note: If a source IP is in allowlist, subsequent checks will be skipped.

IP Reputation

Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the SRC field in the IP header, or the X-Forwarded-For: and X-Real-IP: HTTP headers.
For details, see Rewriting Requests.

Geo IP

Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the SRC field in the IP header, or the X-Forwarded-For: and X-Real-IP: HTTP headers.
For details, see Rewriting Requests.
Source IP address of the client in the IP layer.

WebSocket security

Host:
URL in HTTP header
Origin:
Upgrade:
Frame Size/Message Size
sec-websocket-extenstions

HTTP Allow Method

Host:
URL in HTTP header
Request method in HTTP header

HTTP Request Limit (HTTP Flood Prevention)

Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the SRC field in the IP header, or the X-Forwarded-For: and X-Real-IP: HTTP headers. For details, see Rewriting Requests.
Cookie:
Session state
URL in the HTTP header
HTTP request body

TCP Connection Number Limit (Malicious IP)

Cookie:
Session state
Source IP address of the client in the IP layer
Source port of the client in the TCP layer

HTTP Request Limit (HTTP Access Limit)

ID field of the IP header
Source IP address of the client depending on your configuration of X-header rules.
This could be derived from either the SRC field in the IP header, or the X-Forwarded-For: and X-Real-IP: HTTP headers. For details, see Rewriting Requests. .
HTTP request body

URL Access

Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the SRC field in the IP header, or the X-Forwarded-For: and X-Real-IP: HTTP headers. For details, see Rewriting Requests.
Host:
URL in HTTP header
Source IP of the client in the IP header

Mobile API Protection

Host:
URL in HTTP header
Token header

Protocol Limits

Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the SRC field in the IP header, or the X-Forwarded-For: and X-Real-IP: HTTP headers. For details, see Rewriting Requests.
Content-Length:
Parameter length
Body length
Header length
Header line length
Count of Range: header lines
Count of cookies

File Protection

Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the SRC field in the IP header, or the X-Forwarded-For: and X-Real-IP: HTTP headers. For details, see Rewriting Requests.
Content-Type: in PUT and POST requests
URL in HTTP header
The body of the file

Bot Deception

Host:
URL in the HTTP header

Cross-site request forgery (CSRF) attacks

<a href>
<form>

Protection for Man-in-the-Browser (MITB) attacks

Host:
URL in HTTP header
Request method in HTTP header
Parameters in URL
Content-Type:

Biometrics Based Detection

Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the SRC field in the IP header, or the X-Forwarded-For: and X-Real-IP: HTTP headers. For details, see Rewriting Requests.
URL
Host:
X-Forwarded-For:

XML Protection

URL
HTTP header
Body

JSON Protection

URL
HTTP header
Body

Signature Based Detection

Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the SRC field in the IP header, or the X-Forwarded-For: and X-Real-IP: HTTP headers. For details, see Rewriting Requests.
HTTP headers
HTML Body
URL in HTTP header
Parameters in URL and request body

SQL Syntax Based Detection

Host:
Cookie:
URL in HTTP header
Parameters in URL and request body

Custom Rule

Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the SRC field in the IP header, or the X-Forwarded-For: and X-Real-IP: HTTP headers. For details, see Rewriting Requests.
URL in the HTTP header
HTTP header
Parameter in the URL

Threshold Based Detection

Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the SRC field in the IP header, or the X-Forwarded-For: and X-Real-IP: HTTP headers. For details, see Rewriting Requests.
URL
Host:
X-Forwarded-For:

Account Takeover

Host:
Cookie:
Parameters in the URL
URL in HTTP header
HTTP body
Client's certificate

API Gateway

Host:
URL in HTTP header
API Key as HTTP parameter in URL
API Key as HTTP header
Source IP address of the client depending on your configuration of API user
Request methods in HTTP header
HTTP Referer depending on your configuration of API user

OpenAPI Validation

Host:
HTTP headers, especially the content-type: headers
URL in HTTP header
Request method in HTTP header
Parameters in URL
Multipart filename

URL Rewriting (rewriting & redirection)

Host:
Referer:
Location:
URL in HTTP header
HTML body

Machine Learning - Anomaly Detection

Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the SRC field in the IP header, or the X-Forwarded-For: and X-Real-IP: HTTP headers. For details, see "Defining your proxies, clients, & X-headers" on page 1.
URL in the HTTP header
Request method in HTTP header
Parameter in the URL, or the HTTP header or body
Content-Type:

Compression

Accept-Encoding:

Cookie Security

Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the SRC field in the IP header, or the X-Forwarded-For: and X-Real-IP: HTTP headers. For details, see Request Limits
Cookie:

Reply from server to client

Web Socket Protocol

Upgrade:

Caching

Host:
HTTP method
Return code
URL in the HTTP header
Content-Type:
HTTP headers
Size in kilobytes (KB) of each URL to cache

Bot Deception

Host:
URL in the HTTP header

Protection for Man-in-the-Browser (MiTB) attacks

Status code
Response body

Biometrics Based Detection

Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the SRC field in the IP header, or the X-Forwarded-For: and X-Real-IP: HTTP headers. For details, see Request Limits
URL
Host:
X-Forwarded-For:
HTTP header
Custom signature
Body
The latest HTTP transaction time
The response content type
Status code

Signature Based Detection (Information Leakage)

Source IP address of the client depending on your configuration of X-header rules. This could be derived from either the SRC field in the IP header, or the X-Forwarded-For: and X-Real-IP: HTTP headers. For details, see Request Limits
HTTP headers
HTML Body
URL in HTTP header
Parameters in URL and body
XML in the body of HTTP POST requests
Cookies
Headers
JSON Protocol Detection
Uploaded filename (MULTIPART_FORM_DATA_FILENAME)

Custom Rule

HTTP response code
Content-Type:

Account Takeover

Status code
HTTP headers
HTML body

URL Rewriting (rewriting)

Host:
Referer:
Location:
URL in HTTP header
HTML body

HTTP Header Security

HTTP headers

User Guide

Sequence of scans

Sequence of scans

Sequence of scans