Manage Custom or Unknown Applications
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Manage Custom or Unknown Applications

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Manage Custom or Unknown Applications

Palo Alto Networks provides weekly application updates to identify new App-ID signatures. By default, App-ID is always enabled on the firewall, and you don't need to enable a series of signatures to identify well-known applications. Typically, the only applications that are classified as unknown traffic—tcp, udp or non-syn-tcp—in the ACC and the traffic logs are commercially available applications that have not yet been added to App-ID, internal or custom applications on your network, or potential threats.
On occasion, the firewall may report an application as unknown for the following reasons:
  • Incomplete data—A handshake took place, but no data packets were sent prior to the timeout.
  • Insufficient data—A handshake took place followed by one or more data packets; however, not enough data packets were exchanged to identify the application.
The following choices are available to handle unknown applications:
  • Create security policies to control unknown applications by unknown TCP, unknown UDP or by a combination of source zone, destination zone, and IP addresses.
  • Request an App-ID from Palo Alto Networks—If you would like to inspect and control the applications that traverse your network, for any unknown traffic, you can record a packet capture. If the packet capture reveals that the application is a commercial application, you can submit this packet capture to Palo Alto Networks for App-ID development. If it is an internal application, you can create a custom App-ID and/or define an application override policy.
  • Create a Custom Application with a signature and attach it to a security policy, or create a custom application and define a custom timeout. Avoid creating Application Override policies because they bypass layer 7 application processing and threat inspection, and use less secure stateful layer 4 inspection instead. Instead, use custom timeouts so that you can control and inspect the application traffic at layer 7.
    A custom application allows you to customize the definition of the internal application—its characteristics, category and sub-category, risk, port, and timeout—and to exercise granular policy control and help eliminate unidentified traffic on your network. Creating a custom application also allows you to correctly identify the application in the
    ACC
    and traffic logs, and is useful in auditing/reporting on the applications on your network. To create a custom application, specify a signature and a pattern that uniquely identifies the application and attach it to a Security policy rule that allows or denies the application.
    For example, if you build a custom application that triggers on a host header www.mywebsite.com, the packets are first identified as web-browsing and then are matched as your custom application (whose parent application is web-browsing). Because the parent application is web-browsing, the custom application is inspected at Layer-7 and scanned for content and vulnerabilities.

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