Network threats can originate from different vectors, including malware and spyware infections due to drive-by downloads, phishing attacks, unpatched servers, and random or targeted denial of service (DoS) attacks, to name a few methods of attack. The ability to react to a network attack or infection requires processes and systems that alert the administrator to an attack and provide the necessary forensics evidence to track the source and methods used to launch the attack.
The advantage that Panorama provides is a centralized and consolidated view of the patterns and logs collected from the managed firewalls across your network. You can use the information from the automated correlation engine alone or in conjunction with the reports and logs generated from a Security Information Event Manager (SIEM), to investigate how an attack was triggered and how to prevent future attacks and loss of damage to your network.
There are several ways that you could be alerted to an incident depending on how you’ve configured the Palo Alto Networks firewalls and which third-party tools are available for further analysis. You might receive an email notification that was triggered by a log entry recorded to Panorama or to your syslog server, or you might be informed through a specialized report generated on your SIEM solution, or a third-party paid service or agency might notify you. For this example, let’s say that you receive an email notification from Panorama. The email informs you of an event that was triggered by an alert for a
Zero Access gent.Gen Command And Control Traffic
that matched against a spyware signature. Also listed in the email are the IP address of the source and destination for the session, a threat ID and the timestamp of when the event was logged.
ACC > Threat Activity
tab, check the
widget for any critical or high severity threats. In the
widget, look into the Matching Objects and click a Match Count value to view the
for the associated incident.
To begin investigating the alert, use the threat ID to search the Threat logs on Panorama (
Monitor > Logs > Threat). 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.
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 (
Monitor > Logs > Traffic) 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.
In addition to the Threat logs, use the victim IP address to filter though the WildFire Submissions logs. The WildFire Submissions logs contain information on files uploaded to the WildFire service for analysis. Because spyware typically embeds itself covertly, reviewing the WildFire Submissions logs tells you whether the victim recently downloaded a suspicious file. The WildFire forensics report displays information on the URL from which the file or .exe was obtained, and the behavior of the content. It informs you if the file is malicious, if it modified registry keys, read/wrote into files, created new files, opened network communication channels, caused application crashes, spawned processes, downloaded files, or exhibited other malicious behavior. Use this information to determine whether to block the application that caused the infection (web-browsing, SMTP, FTP), make more stringent URL Filtering rules, or restrict some applications/actions (for example, file downloads to specific user groups).
If WildFire determines that a file is malicious, a new antivirus signature is created within 24-48 hours and made available to you. If you have a WildFire subscription, the signature is made available within 30-60 minutes as part of the next WildFire signature update. As soon as the Palo Alto Networks next-generation firewall has received a signature for it, if your configuration is configured to block malware, the file will be blocked and the information on the blocked file will be visible in your threat logs. This process is tightly integrated to protect you from this threat and stems the spread of malware on your network.
The Data Filtering log (
Monitor > Logs > Data Filtering) is another valuable source for investigating malicious network activity. While you can periodically review the logs for all the files that you are being alerted on, you can also use the logs to trace file and data transfers to or from the victim IP address or user, and verify the direction and flow of traffic: server to client or client to server. To recreate the events that preceded and followed an event, filter the logs for the victim IP address as a destination, and review the logs for network activity.
Because Panorama aggregates information from all managed firewalls, it presents a good overview of all activity in your network. Some of the other visual tools that you can use to survey traffic on your network are the
Traffic Map, and the
Threat Monitor. The threat map and traffic map (
Monitor > AppScope > Threat Map
Traffic Map) allow you to visualize the geographic regions for incoming and outgoing traffic. It is particularly useful for viewing unusual activity that could indicate a possible attack from outside, such as a DDoS attack. If, for example, you do not have many business transactions with Eastern Europe, and the map reveals an abnormal level of traffic to that region, click into the corresponding area of the map to launch and view the ACC information on the top applications, traffic details on the session count, bytes sent and received, top sources and destinations, users or IP addresses, and the severity of the threats detected, if any. The threat monitor (
Monitor > AppScope > Threat Monitor) displays the top ten threats on your network, or the list of top attackers or top victims on the network.