Introduction

Security engineering plays a crucial role in safeguarding organizations against cyber threats. One fundamental aspect of security engineering is the collection and analysis of security event data. Security event data contains information about various activities, incidents, and anomalies that occur within an organization's network or systems. To effectively manage and respond to security threats, it is essential to understand the various data formats used for storing and transmitting security event data. In this blog, we will explore some of the major security event data formats, including Syslog, CEF, CIM, CSNF, OCSF, and others.

Syslog

Syslog is one of the oldest and most widely used formats for logging and transmitting event data in Unix and Unix-like operating systems. It is a simple and lightweight protocol that enables the collection and storage of log messages from various network devices and applications. Syslog messages are typically structured as text-based records with a timestamp, severity level, and message content. These messages can be sent to a central Syslog server for aggregation and analysis.

Syslog is highly customizable, allowing organizations to define their message formats and filter log data based on various criteria. The format is not standardized, which means that different devices and applications may generate Syslog messages in slightly different formats. However, this flexibility can also make it challenging to parse and analyze Syslog data effectively.

Common Event Format (CEF)

The Common Event Format (CEF) is a structured log format developed by ArcSight (now part of Micro Focus) to standardize event data from various security devices and applications. CEF provides a consistent format for representing security events, making it easier to integrate data from different sources into a central security information and event management (SIEM) system.

CEF logs include predefined fields such as event name, severity level, source and destination IP addresses, and more. This standardized format simplifies the task of parsing and normalizing event data, enabling security analysts to quickly identify and respond to threats.

Common Information Model (CIM)

The Common Information Model (CIM) is another standard for organizing and describing security event data. CIM is an initiative by the Security Content Automation Protocol (SCAP) community to create a common language and data model for representing security-related information. CIM defines a set of standardized data fields and relationships between them, allowing organizations to exchange and correlate security event data more effectively.

CIM aims to improve interoperability among security tools and platforms by providing a common framework for data representation. It covers a wide range of security-related data, including vulnerabilities, incidents, assets, and more. Implementing CIM-compliant data structures can enhance the consistency and efficiency of security event data management.

Common Security Normalization Format (CSNF)

The Common Security Normalization Format (CSNF) is a format developed by the Trusted Automated Exchange of Indicator Information (TAXII) community for exchanging threat intelligence data. CSNF focuses on normalizing and standardizing threat intelligence information, making it easier for organizations to share and consume data from different sources.

CSNF provides a structured format for representing indicators of compromise (IOCs), such as IP addresses, domains, and malware signatures. By using a common format, security teams can better correlate and analyze threat intelligence data to identify emerging threats and vulnerabilities.

Open Cybersecurity Format (OCSF)

The Open Cybersecurity Format (OCSF) is an open standard developed by the OASIS consortium for sharing and exchanging cybersecurity threat intelligence. OCSF defines a flexible and extensible format for representing threat intelligence data, making it easier for organizations to collaborate and share information about emerging threats.

OCSF allows organizations to define custom data fields and attributes to suit their specific threat intelligence needs. This flexibility enables the inclusion of diverse data types, such as indicators, tactics, techniques, and procedures (TTPs), and contextual information related to security incidents.

JavaScript Object Notation (JSON)

JSON is a lightweight, human-readable data interchange format commonly used for various purposes, including security event data. JSON is known for its simplicity and ease of use, making it a popular choice for transmitting structured data over networks and APIs.

In the context of security engineering, organizations often use JSON to represent security event data in a structured format. JSON allows for nested data structures, making it suitable for representing complex event details and related information. Security event data in JSON format can be easily parsed and manipulated by various programming languages and tools.

Extensible Markup Language (XML)

XML is another markup language used for representing structured data, including security event data. Like JSON, XML is human-readable and allows for the creation of custom data schemas. It has been used in various security standards and protocols, such as Security Assertion Markup Language (SAML) and Structured Threat Information eXpression (STIX).

XML provides a way to define complex data structures with nested elements and attributes. It is commonly used in security information exchange protocols and formats due to its versatility and extensibility. However, XML can be more verbose and harder to read than JSON, which may impact its usability in some cases.

Binary Formats (e.g., PCAP)

While most security event data formats are text-based, some security engineering tasks require the use of binary formats. Packet capture (PCAP) is a well-known binary format used for recording network traffic at the packet level. PCAP files store packets in their raw binary form, including all protocol headers and payload data.

PCAP files are valuable for network forensics and intrusion detection, as they allow analysts to replay network traffic and examine packet-level details. However, working with binary formats like PCAP requires specialized tools and expertise, making it less accessible for general security event data management.

Conclusion

In the field of security engineering, the proper collection, storage, and analysis of security event data are critical for identifying and mitigating cyber threats effectively. Understanding the major security event data formats, such as Syslog, CEF, CIM, CSNF, OCSF, JSON, XML, and binary formats like PCAP, is essential for building robust security monitoring and incident response capabilities.

Each format has its advantages and limitations, and the choice of format often depends on the specific use case, the type of data being collected, and the compatibility with existing security tools and platforms. By selecting the appropriate data format and implementing standardized data structures, organizations can enhance their ability to detect, respond to, and prevent security incidents, ultimately improving their overall cybersecurity posture. Security event telemetry and observability are essential components of modern security practices, enabling organizations to gain valuable insights into their network and system activities while strengthening their defenses against evolving threats. Observability pipelines like Observo.ai are a vital tool for supporting the work of security engineers.