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Administration Guide

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Credential phishing prevention

When credential phishing prevention is enabled, the FortiGate scans for corporate credentials submitted to external websites and compares them to sensitive credentials stored in the corporate domain controller. Based on the configured antiphishing rules in proxy mode web filter profiles, the FortiGate will block the URL or alert the user if the credentials match ones that are stored on the corporate domain controller.

  • The corporate domain controller must be configured on the credential-store. Credentials are matched based on sAMAccountName. UPN format is not currently supported.
  • The antiphishing profile defines the corporate domain controller, antiphishing check option, default action if no rules match, antiphishing status, and so on.
  • Inspection entries in the profile define what action occurs when the submission request matches the specified FortiGuard categories.
  • The profile scans for pre-defined and custom username and password fields in the HTTP request, such as username, auth, and password. You can evaluate custom fields by configuring custom patterns.
  • The URL filter defines individual URLs that the antiphish action (block or log) is applied to when the URL submission request matches.
Note

Web-based URL filter actions and FortiGuard category-based filtering have higher priority than antiphishing URL filter actions and FortiGuard filtering:

  • If a request is blocked by the web-based URL filter or FortiGuard filter, there is no further antiphishing scanning. Antiphishing scanning only happens after the web-based URL filtes and FortiGuard filters allow the traffic.
  • If a submission matches an entry in the URL filter table that has an antiphishing action, the defined action is taken. No further FortiGuard category-based rules are applied.
  • Like firewall rules, the URL filter table and Fortiguard category-based antiphishing rules use a top-down priority. The rule that matches first is the one that is used.

In this example, URLs that match FortiGuard category 37 (social networking) will be blocked and other categories will be logged.

To configure credential phishing prevention:
  1. Configure the corporate domain controller:
    config credential-store domain-controller
        edit "win2016"
            set domain-name "corpserver.local"
            set username "Administrator"
            set password ENC password
            set ip <server_ip>
        next
    end
    
    Note

    The domain controller entry name must be the hostname of the DC (win2016 in the example). Both it and the domain name are case sensitive.

  2. Configure the antiphishing profile, which includes the FortiGuard category rule:
    config webfilter profile
        edit "<profile-name>"
            set feature-set proxy
            ...
            config web
                ...
            end
            config antiphish
                set status enable
                set domain-controller "win2016"
                set default-action block
                set check-uri enable
                set check-basic-auth enable
                set max-body-len 65536
                config inspection-entries
                    edit "inspect-37"
                        set fortiguard-category 37
                        set action block
                    next
                    edit "inspect-others"
                        set fortiguard-category all
                        set action log
                    next
                end
                config custom-patterns
                    edit "customer-name"
                        set category username
                    next
                    edit "customer-passwd"
                       set category password
                    next
                end
            end
            ...
            set web-antiphishing-log enable
        next
    end
    • check-uri enables support for scanning HTTP GET URI parameters.
    • check-basic-auth enables support for scanning the HTTP Basic Auth field.
  3. Configure the URL filter to scan specific URLs.

    The antiphish action is added to the URL filter table entry, and the URL filter is applied to the webfilter profile.

    config webfilter urlfilter
        edit 1
            set name "antiphish-table"
            config entries
                edit 1
                    set url "www.example.com"
                    set type simple
                    set antiphish-action block
                    set status enable
                    set referrer-host ''
                next
            end
        next
    end
    config webfilter profile
        edit "<profile-name>"
            config web
                set urlfilter-table 1
            end
            ...
        next
    end
  4. Optionally, define custom patterns to scan fields other than the built-in username and password keywords are needed:
    config webfilter profile
        edit "<profile-name>"
            config custom-patterns
                    edit "customer-name"
                        set category username
                    next
                    edit "customer-passwd"
                       set category password
                    next
                end
            end
        next
    end 
    

Credential phishing prevention

When credential phishing prevention is enabled, the FortiGate scans for corporate credentials submitted to external websites and compares them to sensitive credentials stored in the corporate domain controller. Based on the configured antiphishing rules in proxy mode web filter profiles, the FortiGate will block the URL or alert the user if the credentials match ones that are stored on the corporate domain controller.

  • The corporate domain controller must be configured on the credential-store. Credentials are matched based on sAMAccountName. UPN format is not currently supported.
  • The antiphishing profile defines the corporate domain controller, antiphishing check option, default action if no rules match, antiphishing status, and so on.
  • Inspection entries in the profile define what action occurs when the submission request matches the specified FortiGuard categories.
  • The profile scans for pre-defined and custom username and password fields in the HTTP request, such as username, auth, and password. You can evaluate custom fields by configuring custom patterns.
  • The URL filter defines individual URLs that the antiphish action (block or log) is applied to when the URL submission request matches.
Note

Web-based URL filter actions and FortiGuard category-based filtering have higher priority than antiphishing URL filter actions and FortiGuard filtering:

  • If a request is blocked by the web-based URL filter or FortiGuard filter, there is no further antiphishing scanning. Antiphishing scanning only happens after the web-based URL filtes and FortiGuard filters allow the traffic.
  • If a submission matches an entry in the URL filter table that has an antiphishing action, the defined action is taken. No further FortiGuard category-based rules are applied.
  • Like firewall rules, the URL filter table and Fortiguard category-based antiphishing rules use a top-down priority. The rule that matches first is the one that is used.

In this example, URLs that match FortiGuard category 37 (social networking) will be blocked and other categories will be logged.

To configure credential phishing prevention:
  1. Configure the corporate domain controller:
    config credential-store domain-controller
        edit "win2016"
            set domain-name "corpserver.local"
            set username "Administrator"
            set password ENC password
            set ip <server_ip>
        next
    end
    
    Note

    The domain controller entry name must be the hostname of the DC (win2016 in the example). Both it and the domain name are case sensitive.

  2. Configure the antiphishing profile, which includes the FortiGuard category rule:
    config webfilter profile
        edit "<profile-name>"
            set feature-set proxy
            ...
            config web
                ...
            end
            config antiphish
                set status enable
                set domain-controller "win2016"
                set default-action block
                set check-uri enable
                set check-basic-auth enable
                set max-body-len 65536
                config inspection-entries
                    edit "inspect-37"
                        set fortiguard-category 37
                        set action block
                    next
                    edit "inspect-others"
                        set fortiguard-category all
                        set action log
                    next
                end
                config custom-patterns
                    edit "customer-name"
                        set category username
                    next
                    edit "customer-passwd"
                       set category password
                    next
                end
            end
            ...
            set web-antiphishing-log enable
        next
    end
    • check-uri enables support for scanning HTTP GET URI parameters.
    • check-basic-auth enables support for scanning the HTTP Basic Auth field.
  3. Configure the URL filter to scan specific URLs.

    The antiphish action is added to the URL filter table entry, and the URL filter is applied to the webfilter profile.

    config webfilter urlfilter
        edit 1
            set name "antiphish-table"
            config entries
                edit 1
                    set url "www.example.com"
                    set type simple
                    set antiphish-action block
                    set status enable
                    set referrer-host ''
                next
            end
        next
    end
    config webfilter profile
        edit "<profile-name>"
            config web
                set urlfilter-table 1
            end
            ...
        next
    end
  4. Optionally, define custom patterns to scan fields other than the built-in username and password keywords are needed:
    config webfilter profile
        edit "<profile-name>"
            config custom-patterns
                    edit "customer-name"
                        set category username
                    next
                    edit "customer-passwd"
                       set category password
                    next
                end
            end
        next
    end