Create a Decryption Profile

Attach Decryption profiles to Decryption policy rules to control the protocol versions, algorithms, verification checks, and session checks the firewall accepts for the traffic defined in the policy rules.
A decryption profile allows you to perform checks on both decrypted traffic and SSL traffic that you choose to exclude from decryption. (If a server breaks SSL decryption technically due to certificate pinning or other reasons, add the server to the Decryption Exclusion list.) Depending on your needs, create Decryption profiles to:
  • Block sessions based on certificate status, including blocking sessions with expired certificates, untrusted issuers, unknown certificate status, certificate status check timeouts, and certificate extensions.
  • Block sessions with unsupported versions and cipher suites, and that require using client authentication.
  • Block sessions if the resources to perform decryption are not available or if a hardware security module is not available to sign certificates.
  • Define the protocol versions and key exchange, encryption, and authentication algorithms allowed for SSL Forward Proxy and SSL Inbound Inspection traffic in the SSL Protocol Settings.
Don’t weaken the main Decryption profile that you apply to most sites to accommodate weaker sites. Instead, create one or more separate Decryption profiles for sites that you need to support but that don’t support strong ciphers and algorithms. You can also create different Decryption profiles for different URL Categories to fine tune security vs. performance for traffic that contains no sensitive material; however, you should always decrypt and inspect all the traffic you can.
After you create a decryption profile, attach it to a decryption policy rule; the firewall then enforces the decryption profile settings on traffic that matches the decryption policy rule.
Palo Alto Networks firewalls include a default decryption profile that you can use to enforce the basic recommended protocol versions and cipher suites for decrypted traffic. However, the best practice is to enable tighter decryption controls as described in SSL Forward Proxy Decryption Profile, SSL Inbound Inspection Decryption Profile, and SSL Protocol Settings Decryption Profile.
Avoid supporting weak protocols or algorithms because they contain known vulnerabilities that attackers can exploit. If you must allow a weaker protocol or algorithm to support a key partner or contractor who uses legacy systems with weak protocols, create a separate Decryption profile for the exception and attach it to a Decryption policy rule that applies the profile only to the relevant traffic (for example, the source IP address of the partner). Don’t allow the weak protocol for all traffic.
  1. Create a new decryption profile.
    Select ObjectsDecryption Profile, Add or modify a decryption profile rule, and give the rule a descriptive Name.
  2. (Optional) Allow the profile rule to be Shared across every virtual system on a firewall or every Panorama device group.
  3. (Decryption Mirroring Only) Enable an Ethernet Interface for the firewall to use to copy and forward decrypted traffic.
    Separate from this task, follow the steps to Configure Decryption Port Mirroring. Be aware of local privacy regulations that may prohibit mirroring or control the type of traffic that you can mirror. Decryption port mirroring requires a decryption port mirror license.
  4. (Optional) Block and control SSL tunneled and/or inbound traffic:
    Although applying a Decryption profile to decrypted traffic is optional, it is a best practice to always apply a Decryption profile to the policy rules to protect your network against encrypted threats. You can’t protect yourself against threats you can’t see.
    Select SSL Decryption:
    • Select SSL Forward Proxy to configure the SSL Forward Proxy Decryption Profile settings to verify certificates, enforce protocol versions and cipher suites, and perform failure checks on SSL decrypted traffic. These settings are active only when this profile is attached to a decryption policy rule configured to perform SSL Forward Proxy decryption.
    • Select SSL Inbound Inspection to configure the SSL Inbound Inspection Decryption Profile settings to enforce protocol versions and cipher suites and to perform failure checks on inbound SSL traffic. These settings are active only when this profile is attached to a decryption policy rule that performs SSL Inbound Inspection.
    • Select SSL Protocol Settings to configure the SSL Protocol Settings Decryption Profile that control minimum and maximum protocol versions and key exchange, encryption, and authentication algorithms to enforce on decrypted SSL traffic. These settings are active when this profile is attached to decryption policy rules that are set to perform either SSL Forward Proxy decryption or SSL Inbound Inspection.
  5. (Optional) Block and control traffic (for example, a URL category) for which you choose to Create a Policy-Based Decryption Exclusion.
    Although applying a Decryption profile to traffic that you choose not to decrypt is optional, it is a best practice to always apply a Decryption profile to the policy rules to protect your network against sessions with expired certificates or untrusted issuers.
    Select No Decryption to configure the Decryption Profile for No Decryption and check the Block sessions with expired certificates and Block sessions with untrusted issuers boxes to validate certificates for traffic that is excluded from decryption. Create policy-based exclusions only for traffic that you choose not to decrypt. If a server breaks decryption for technical reasons, don’t create a policy-based exclusion, add the server to the SSL Decryption Exclusion list (DeviceCertificate ManagementSSL Decryption Exclusion).
    These setting are active only when the decryption profile is attached to a decryption policy rule that disables decryption for certain traffic.
  6. (Optional) Block and control decrypted SSH traffic.
    Select SSH Proxy to configure the SSH Proxy Decryption Profile and configure settings to enforce supported protocol versions and to block sessions if system resources are not available to perform decryption.
    These settings are active only when the decryption profile is attached to a decryption policy rule that decrypts SSH traffic.
  7. Add the decryption profile when you Create a Decryption Policy Rule.
    The firewall applies the decryption profile to and enforces the profile’s settings on the traffic that matches the decryption policy rule.
  8. Commit the configuration.

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