Take a Packet Capture for Unknown Applications

Palo Alto Networks firewalls automatically generate a packet capture for sessions that contain an application that the firewall cannot identify. Typically, the only applications that are classified as unknown traffic—tcp, udp, or non-syn-tcp—are commercially available applications that do not yet have App-ID signatures, are internal or custom applications on your network, or potential threats. You can use these packet captures to gather more context related to the unknown application or use the information to analyze the traffic for potential threats. You can also Manage Custom or Unknown Applications by controlling them through security policy or by writing a custom application signature and then creating a security rule based on the custom signature. If the application is a commercial application, you can submit the packet capture to Palo Alto Networks to have an App-ID signature created.
  1. Verify that unknown application packet capture is enabled (this option is enabled by default).
    1. To view the unknown application capture setting, run the following CLI command:
      admin@PA-220>
      show running application setting | match “Unknown capture”
    2. If the unknown capture setting option is off, enable it:
      admin@PA-220>
      set application dump-unknown yes
  2. Locate unknown TCP and UDP applications by filtering the traffic logs.
    1. Select
      Monitor
      Logs
      Traffic
      .
    2. Click
      Add Filter
      , create the unknown TCP portion of the filter (
      Connector
      = “and”,
      Attribute
      = “Application”,
      Operator
      = “equal”, and enter “unknown-tcp” as the
      Value
      ), and then click
      Add
      to add the query to the filter.
      add-log-filter-pcap-unknown-apps-tcp-10.png
    3. Create the unknown UDP portion of the filter (
      Connector
      = “or”,
      Attribute
      = “Application”,
      Operator
      = “equal”, and enter “unknown-udp” as the
      Value
      ), and then click
      Add
      to add the query to the filter.
      add-log-filter-pcap-unknown-apps-tcp-udp-10.png
    4. Click
      Apply
      to place the filter in the log screen query field.
  3. Click the
    Apply Filter
    arrow next to the query field to run the filter and then click the packet capture icon packet_capture_icon.png to view the packet capture or
    Export
    it to your local system.
    pcap-unknown-apps-10.png

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