SSL Inbound Inspection
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Network Security

SSL Inbound Inspection

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SSL Inbound Inspection

SSL Inbound Inspection protects internal servers from threats posed by SSL/TLS traffic originating from an external server or the internet.
Where Can I Use This?What Do I Need?
  • NGFW
  • Prisma Access
No requirements.
Configure SSL Inbound Inspection to decrypt and inspect inbound SSL/TLS traffic from clients to targeted network servers and block suspicious sessions. For example, suppose a malicious actor wants to exploit a known vulnerability with your web server. Inbound SSL/TLS decryption provides visibility into the traffic, enabling the Next-Generation Firewall (NGFW) to respond to the threat proactively.
SSL Inbound Inspection works similarly to SSL Forward Proxy, except the direction of traffic it focuses on differs. The NGFW acts as a meddler in the middle between an external client and an internal server. The NGFW creates two separate and secure sessions: one between the client and itself, and another between itself and the server. It also generates a new session key for each secure session. SSL Inbound Inspection also supports SSL session resumption because the NGFW functions as a proxy device.
The NGFW can't decrypt some sessions, such as sessions with client authentication or pinned certificates, because it is a proxy device. It also doesn't support high availability (HA) sync for decrypted SSL sessions.
SSL Inbound Inspection requires installation of the certificate and private key of each internal server you want to protect onto the NGFW or management platforms for NGFW and Prisma Access. The NGFW validates that the certificate sent by the targeted server during the SSL/TLS handshake matches a certificate in your decryption policy rule. If there is a match, the NGFW forwards the server certificate to the client requesting server access and establishes a secure connection.
The TLS versions that your web server supports determine how you should install the server certificate and key. If your web server supports TLSv1.2 and Rivest, Shamir, Adleman (RSA) or Perfect Forward Secrecy (PFS) key exchange algorithms and your end-entity (leaf) certificate is signed by intermediate certificates, we recommend uploading a certificate chain (a single file). Uploading the chain avoids client-side server certificate authentication issues.
TLSv1.3 removes support for the RSA key exchange algorithm.
TLSv1.3 connections are handled differently than TLSv1.2 connections. During TLSv1.3 handshakes, the NGFW sends the client the same certificate or certificate chain that it receives from the server. As a result, uploading the server certificate and private key to the NGFW is sufficient if you correctly set up your web server. For example, if your server’s leaf certificate is signed by intermediate certificates, install the chain of certificates on the server to avoid client-side server authentication issues.
Multiple Certificate Support
Create separate decryption profiles for servers with different security capabilities. Configure the SSL Protocol Settings for the highest level of security that a server supports, but consider performance to ensure that the NGFW and Prisma Access resources can handle the higher processing load that higher security protocols and algorithms require. For example, if a set of servers supports only RSA, configure a decryption profile that exclusively supports RSA. If a server supports both RSA and PFS, select RSA and PFS key exchange algorithms.
When you configure SSL Inbound Inspection, the proxied traffic does not support DSCP code points or QoS.
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