Syslog and Common Event Format (CEF) event collections are crucial components of a robust security infrastructure. They are instrumental in collecting, recording and analyzing the security-related activities in your IT environment. As part of the SC-200 Microsoft Security Operations Analyst certification exam, understanding the design and configuration of Syslog and CEF event collections becomes significant.
Syslog is a standard for message logging that allows systems and users to generate and collect logs for various types of messages, including system, security, and event messages. Its design is characterized by effectiveness and interoperability, proving exceptionally useful in troubleshooting and security contexts.
On the other hand, CEF (Common Event Format) is a universal log format supported by many security tools, providing a standardized structure for logs and event records.
Understanding Syslog Design and Configuration
Firstly, understanding the design and configuration of Syslog event collections is imperative. Syslog uses a client-server architecture where the source device is the client, and the device receiving the log data is the server.
In Syslog, messages are differentiated and organized using Facilities and Severities. Facilities are differentiated by integers, each representing a different system module that can generate log messages. Severities categorize the urgency of each log message, identified with an integer (0-7), where 0 means an emergency and 7 means debug-level information.
Configuration of Syslog differs based on the operating system and the service generating the logs. In general, you need to edit system and application-wide configuration files to direct their Syslog messages to the correct place. Configuring Syslog on Microsoft systems requires additional tools or services as Windows does not natively support Syslog.
Understanding CEF Design and Configuration
CEF provides similar functionality as syslog but structures its data differently to promote uniformity and easy parsing. CEF logs start with a standard header that includes the device product, device version, device event classification ID, name, and severity. After the header, in the extension section, additional details are given in a key-value pair format.
CEF is a text-based format, making it accessible for any system to generate and read. Its key-value pair structure leads to clear, readable logs that can be easily parsed by log management solutions.
Microsoft has an excellent Log Analytics agent that can be used to ingest CEF formatted data into Azure Sentinel, in addition to Azure Monitor logs.
Examples
Consider a scenario where we want to configure a Syslog server on a Linux machine. Here is how you could accomplish it:
- First, install the syslog server package. On a Ubuntu machine, you can type
sudo apt-get install rsyslog. - After installation, we need to configure Rsyslog to accept log messages from the network by editing the Rsyslog configuration file situated at “/etc/rsyslog.conf.”
- At the end of the module section, we add the following lines:
$ModLoad imudp $UDPServerRun 514 - Lastly, restart your Rsyslog service with
sudo service rsyslog restart.
Now your rsyslog server is ready to accept and process Syslog messages over the network.
For CEF, a typical event might look like:
CEF:0|Microsoft|Azure Sentinel|1.0|123|Example rule|1|cs1Label=UserName cs1=jdoe dst=10.0.0.1
The number ‘0’ right after CEF indicates the version of CEF being used. ‘Microsoft’ and ‘Azure Sentinel’ identify the device vendor and product, respectively. ‘1.0’ is the device version, followed by a unique ID (‘123’ in this case) identifying the specific event or rule that triggered the event.
Designing and configuring Syslog and CEF event collections is a vital part of maintaining and securing an IT infrastructure. Adept handling of these tools can significantly enhance the potential of security analytics, which making it crucial learning for anyone considering taking the SC-200 Microsoft Security Operations Analyst certification exam.
Practice Test
True or False: Syslog is a protocol used to collect and store messages from devices to a specific server.
- True
- False
Answer: True
Explanation: Syslog is indeed a protocol used in computing for message logging. It allows separation of the software that generates messages, the system that stores them, and the software that reports and analyzes them.
Which of the following are Syslog levels from high to low severity?
- A. Debug
- B. Alert
- C. Emergency
- D. Critical
Answer: C. Emergency, B. Alert, D. Critical, A. Debug
Explanation: The syslog protocol has eight levels of severity. From high to low, they are: Emergency, Alert, Critical, Error, Warning, Notice, Informational, and Debug.
True or False: Cisco Express Forwarding (CEF) is a Microsoft technology for optimizing network performance.
- True
- False
Answer: False
Explanation: CEF is actually a Cisco technology, not one from Microsoft. It optimizes network performance on Cisco certified networks.
In a Microsoft environment, which of the following protocols can be used to send log data to an Azure Log Analytics workspace?
- A. Syslog
- B. SNMP
- C. TCP/IP
- D. HTTP/HTTPS
Answer: A. Syslog
Explanation: Azure Log Analytics can collect data from Syslog. While HTTP/HTTPS are used for transmitting messages, it is through the Syslog protocol that log data can be directly sent.
True or False: It is not necessary to design the structure of the Syslog and CEF Event Collections.
- True
- False
Answer: False
Explanation: It’s important to properly design the structure of Syslog and CEF Event Collections to ensure effective log management and to prevent potential loss of critical log data.
How many parts are included in a Syslog message structure?
- A. Two
- B. Three
- C. Five
- D. Seven
Answer: D. Seven
Explanation: A Syslog message has seven parts: priority, version, timestamp, hostname, app-name, process-id and the actual message.
What does the CEF Event Prefix abbreviation stand for?
- A. Common Event Format
- B. Configuration Express Forwarding
- C. Common Express Forwarder
- D. Configuration Event Format
Answer: A. Common Event Format
Explanation: CEF stands for Common Event Format, which is a standard and open log management format.
True or False: The CEF syslog messages contain a configurable field delimiter.
- True
- False
Answer: True
Explanation: Yes, CEF syslog messages do contain a configurable field delimiter, which is generally set as the pipe (|) symbol.
Which of the following are possible destinations for Syslog messages?
- A. Console
- B. Terminal lines
- C. Memory buffer
- D. All of the above
Answer: D. All of the above
Explanation: Syslog messages can be sent to a console, to terminal lines, or kept in a memory buffer, according to the network requirements.
True or False: Azure Sentinel natively supports log data from any Syslog or CEF source.
- True
- False
Answer: True
Explanation: Azure Sentinel, Microsoft’s scalable, cloud-native, security information event management (SIEM) and security orchestration automated response (SOAR) solution, does support receiving log data from any Syslog or CEF source.
Interview Questions
What is Syslog protocol mainly used for in a network infrastructure?
Syslog protocol is used for system logging. It provides a standard for forwarding system and application messages to a designated Syslog server, aiding in network management and security audits.
What is Cisco Express Forwarding (CEF)?
Cisco Express Forwarding (CEF) is an advanced layer 3 switching technology used in networks. It optimizes the network performance and scalability for networks with large and dynamic traffic patterns, such as the internet.
Can Windows machines natively send logs to a Syslog server?
No, natively Windows doesn’t support Syslog. However, it’s possible to use third-party tools to send event logs in the Syslog format.
What are FIB and Adjacency Tables in the context of CEF (Cisco Express Forwarding)?
FIB (Forwarding Information Base) and Adjacency tables are the key elements of CEF. FIB provides a mirror image of the routing information while the Adjacency table maintains layer 2 next hop addresses for all FIB entries.
Which protocol TCP/UDP does Syslog use?
Syslog primarily uses UDP protocol for all the message communications, however, it can also use TCP where reliable delivery of log messages is required.
How does CEF benefit packet-switching speed?
CEF enhances packet-switching speed by maintaining a large routing table (the FIB). Instead of performing multiple lookups in the routing table, CEF only requires one lookup, drastically reducing the time required to switch packets.
What is the standard Syslog port number?
The standard Syslog port is 514 for UDP and it is 601 for TCP.
What is the main purpose of configuring Syslog in a network environment?
Configuring Syslog in a network environment allows administrators to centralize the system and application messages of all network devices for easy management, monitoring, and auditing.
How does CEF handle load balancing when there are multiple equal-cost paths to the destination?
CEF supports per-destination and per-packet load balancing. If configured for per-destination load balancing (the default mode), CEF alternates across the multiple paths based on the destination address.
How is a Syslog message’s severity level represented in the protocol?
A Syslog message’s severity level is represented by a single digit integer ranging from 0 to 7, where 0 stands for Emergency (the most severe level), while 7 represents Debug (the least severe).
Can Syslog handle the logging needs of both servers and network devices simultaneously?
Yes, Syslog can handle logs from network devices such as routers, switches, and firewalls, in addition to logs from servers or any devices that can generate logs in the Syslog format.
Where is the Switching Database Manager (SDM) in relation to Cisco Express Forwarding (CEF)?
The SDM is a part of CEF. SDM templates are used to optimize system resources in the device to enhance the system’s specific features, depending on the network requirements.
Is it possible to filter syslog messages into different severity levels?
Yes, the Syslog protocol provides eight different severity levels that range from Emergency (0) to Debug (7). As a result, it is possible to filter messages according to their severity levels.
What benefits does CEF offer over process switching and fast switching?
CEF offers increased network performance and scalability, and reduces CPU utilization. It also supports advanced intel networking functions, such as QoS (Quality of Service) and security.
How do Syslog servers help improve network security?
Syslog servers centralize log information from various network devices, which can be analyzed and monitored for suspicious activities. This can help in quick identification and rectification of security threats.
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