A firewall monitors traffic into and out of the environment it was developed to protect. Some firewalls also offer visibility into the source and type of traffic coming into this environment. A firewall is configured using rules. To be successful, the ruleset of a firewall must be augmented with a successful logging feature. Show
The logging feature records how the firewall manages traffic types. The logs provide organizations with information about, for example, source and destination IP addresses, protocols, and port numbers and can be used by a SIEM to help investigate an attack. Firewall LoggingA firewall, at its most basic form, is created to stop connections from suspicious networks. It inspects the source address, destination address, and the destination port of all connections, and decides if a network can be trusted. For simplicity, we can aggregate information on the source address, source port, and destination address and port. We can view this information as an identifying quality of any attempt to connect, as tracked by the firewall. This quality is similar to a set of rules that determine which connections are permitted and which must be denied. If this identifying quality holds information that is the same as a permitted connection, then the source address can create a connection with the destination address on the permitted port. Thus, the traffic is allowed into the network. The success of any firewall, therefore, typically relies on the rules used to configure it. The firewall monitors traffic into and out of the environment it was created to safeguard and provides visibility into the type and source of traffic entering this environment. It typically serves two purposes:
To be most effective, a firewall ruleset must be augmented with a successful logging feature. The logging feature documents how the firewall deals with traffic types. These logs offer insights into, for example, source and destination IP addresses, protocols, and port numbers. When and why firewall logging is useful
Linux Firewall LogsThe Linux kernel has a packet filtering framework called netfilter. This framework lets you permit, drop, and modify the traffic that comes in and out of a system. A tool, iptables furthers this functionality with a firewall, which you can configure using rules. Additional programs, like fail2ban, also rely on iptables to block attackers. How does iptables work?Iptables is a command-line interface to the packet filtering capabilities in netfilter. However, we won’t distinguish between iptables and netfilter for the purposes of this article. To keep things clear we will refer to the entire concept as iptables. The packet filtering function offered by iptables is structured as tables, targets,
and chains. Put simply, a table lets you process packets in a certain way. The filter table is the default table. When a packet enters or exits (according to the chain) iptables compares it against rules in these chains one at a time. When it identifies a match, it isolates the target and carries out the required action. If it doesn’t identify a match with any of the rules it carries out the action specified by the default policy of the chain. The default policy also acts as a target. By default, all chains have a policy of permitting packets. Working with and interpreting iptable firewall logsTo create firewall logs, the kernel needs to be firewall logging enabled. By default, matched packets are logged as The majority of the IP packet header fields are disclosed when a packet matches a rule with the LOG target. By default, firewall log messages are written to /var/log/messages. Windows Firewall LogsMicrosoft Windows has a built-in firewall. The firewall does not log any traffic, by default. However, you can choose to configure the firewall to log connections that are permitted and traffic that is dropped. If you authorize Windows firewall logging, it creates “pfirewall.log” files in its directory hierarchy. You can see the Windows firewall log files via Notepad. How to enable windows 10 firewall logsGo to Windows Firewall with Advanced Security. Right-click on Windows Firewall with Advanced Security and click on Properties. Figure 1: How to setup logging and tracking: SourceThe Windows Firewall with Advanced Security Properties box should appear. You can move between Domain, Private, and Public Firewall profiles. Generally, you should configure the Domain or Private Profile. Let’s see how to create Windows Firewall logging on a Windows Firewall Private Profile. The steps below will work both for a public profile or a domain. Click Private Profile > Logging > Customize Figure 2: How to setup logging and tracking: SourceGo to “Log Dropped Packets” and switch to Yes Generally, we turn on logging for “Log Dropped Packets” only. We won’t log successful connections as successful connections generally are not so helpful when resolving problems. Copy the default path for the log file. ( %systemroot%\system32\LogFiles\Firewall\pfirewall.log ) and then Press OK Open File Explorer and go to where the Windows Firewall log is kept. ( %systemroot%\system32\LogFiles\Firewall\) . You will see, in the Firewall folder, a pfirewall.log Copy the pfirewall.log to your desktop. This will let you open the file with no firewall warnings. Interpreting the windows firewall logsYour Windows Firewall log will look something like the following: Figure 2: Track internet activity with windows firewall log: SourceHere is an analysis of the key aspects of the above log:
How to Analyze Firewall LogsFirewall logging, especially of permitted events, can be helpful for discovering potential network security threats. An organization generally places strict protection on assets that should not be freely accessible. These may include internal corporate networks and the workstations of employees. Typically, no unmediated inbound connection to these systems is allowed. What to look for when performing firewall log analysisOnce you have gathered the firewall logs and started the process of analyzing the logs, you can decide what to look for in the log. You should refrain from only looking for “harmful” events. Your firewall logs not only help you isolate compromises and incidents, but they can also help you specify the normal operations of the firewall. One way to see whether the behavior that has been logged is suspicious is to see what the normal operations are and then to note the exceptions. Some events should always cause suspicion and prompt further investigation. They are as follows:
Log Analysis and Alerting with ExabeamLog Management and Next Generation SIEMsLog management is challenging, and it is becoming increasingly so with the rapid growth of network devices, microservices and cloud services, endpoints, and the vast increase in data and traffic volumes. Next-generation Security Information and Event Management (SIEM) solutions can assist you with your management of security-related log events and help you learn about events that are relevant to a security incident. Features of next-generation SIEMs:
Which two actions does a firewall take when a security profile's action is configured as reset server Choose two?In a Security Profile, which action does a firewall take when the profiles action is configured as Reset Server? (Choose two.) For UDP sessions, the connection is dropped. The traffic responder is reset.
Which two items describe configuration conditions that enable the firewall to generate traffic log entries?The correct answer was "Security zone, Security Policy Rule". Traffic must be decrypted by the firewall. Traffic is allowed by a Security policy rule. The matching Security policy rule must enable logging.
Which two protocols can be configured in a certificate profile to verify that a certificate is still valid?The two methods available to check certificate revocation status are OCSP and CRLs. A firewall can use OCSP, CRLs, or both to verify certificate revocation status for SSL decryption. *If you configure both methods on a firewall, the firewall FIRST TRIES OCSP.
Which two Palo Alto Networks subscriptions services are required for IoT security?IoT Security subscriptions offer two options:. IoT Security Subscription. : This subscription requires that you also have a Cortex Data Lake instance, which stores the data logs from firewalls. ... . IoT Security, Does Not Require Data Lake Subscription.. |