Review Threat Logs
To begin investigating the alert, use the threat ID to search the Threat logs on Panorama (
). From the Threat logs, you can find the IP address of the victim, export the packet capture (PCAP) by clicking the download icon in the log entry, and use a network analyzer tool such as WireShark to review the packet details. In the HTTP case, look for a malformed or bogus HTTP REFERER in the protocol, suspicious host, URL strings, the user agent, the IP address and port in order to validate the incident. Data from these pcaps is also useful in searching for similar data patterns and creating custom signatures or modifying security policy to better address the threat in the future.
As a result of this manual review, if you feel confident about the signature, consider transitioning the signature from an alert action to a block action for a more aggressive approach. In some cases, you may choose to add the attacker IP to an IP block list to prevent further traffic from that IP address from reaching the internal network.
If you see a DNS-based spyware signature, the IP address of your local DNS server might display as the
Victim IPaddress. Often this is because the firewall is located north of the local DNS server, and so DNS queries show the local DNS server as the source IP rather than showing the IP address of the client that originated the request.
If you see this issue, enable the DNS sinkholing action in the Anti-Spyware profile in security rules to identify the infected hosts on your network. DNS sinkholing allows you to control outbound connections to malicious domains and redirect DNS queries to an internal IP address that is unused; the sinkhole that does not put out a response. When a compromised host initiates a connection to a malicious domain, instead of going out to the internet, the firewall redirects the request to the IP address you defined and it is sinkholed. Now, reviewing the traffic logs for all hosts that connected to the sinkhole allows you locate all compromised hosts and take remedial action to prevent the spread.
To continue with the investigation on the incident, use the information on the attacker and the victim IP address to find out more information, such as:
- Where is the attacker located geographically? Is the IP address an individual IP address or a NATed IP address?
- Was the event caused by a user being tricked into going to a website, a download, or was it sent through an email attachment?
- Is the malware being propagated? Are there other compromised hosts/endpoints on the network?
- Is it a zero-day vulnerability?
The log details for each log entry display the related logs for the event. This information points you to the Traffic, Threat, URL Filtering or other logs that you can review and correlate the events that led to the incident. For example, filter the Traffic log (
) using the IP address as both the source and the destination IP to get a complete picture of all the external and internal hosts/clients with which this victim IP address has established a connection.
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