Bro Intrusion Detection
Presented by
Deeksha .D
Roll no:24JJ1DA304
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Introduction
Bro, now known as Zeek, is a powerful open-source network-based
intrusion detection system (NIDS). Developed in the 1990s, it monitors
network traffic in real time. It detects complex threats like malware and
data exfiltration. Security professionals worldwide use Bro.
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Key Features for Bro
Real-time Event- Deep
Monitoring Driven Protocol
Analysis
Analyzes Flexible
network traffic detection via Examines HTTP,
as it happens. event-driven DNS, FTP, SSL,
architecture. and more.
Detailed
Logs
Generates
structured and
comprehensive
log files.
Bro offers robust features for network security. Its powerful scripting language
allows extensive customization for diverse use cases.
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Core Components and Architecture
Packet Capture
Passively monitors network traffic.
Event Engine
Processes packets for network events.
Policy Engine
Interprets scripts for security rules.
Alerting and Logging
Generates alerts for suspicious activities.
Scripting Language
Allows custom detection policies.
Bro's architecture is designed for efficient threat detection. Each component plays a vital role in its robust functionality.
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Introduction to the Bro
Scripting Language
Event-Driven
Follows an event-driven programming model.
Declarative Syntax
Defines detection rules declaratively.
Built-in Functions
Includes tools for traffic analysis.
External Integration
Connects with threat intelligence feeds.
The Bro scripting language is powerful and flexible. It allows users to write custom
security policies. For example, you can detect suspicious DNS queries based on
domain reputation. This flexibility enables precise threat detection.
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Analyzing Bro Logs: Connection
Data
1 2
conn.log Suspicious Patterns
Records connection information. Identifies unusual communication.
3
C2 Traffic
Detects command and control.
The conn.log is crucial for security analysis. It helps in identifying suspicious
communication patterns, such as large data transfers or unusual ports. Analyzing
these logs can reveal command and control (C2) traffic. For instance, monitoring
connections to known malicious IPs is a common use case.
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Analyzing Bro Logs: HTTP
Traffic
http.log Web Attacks
Captures HTTP Identifies SQL injection, XSS,
request/response data. etc.
Malware Detection
Detects downloads and exploits.
The http.log is essential for web security. It captures detailed HTTP
traffic, including URLs, headers, and user agents. This data helps in
identifying web-based attacks like SQL injection and cross-site scripting.
It also aids in detecting malware downloads. Analyzing suspicious user-
agent strings is a key method.
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Common Use Cases
Intrusion Detection Data Loss Prevention
Identifies and responds to malicious activity. Monitors sensitive data exfiltration.
Malware Analysis Compliance Monitoring
Analyzes network traffic for infections. Ensures adherence to security policies.
Bro offers diverse applications in network security. It excels at network intrusion detection. It also aids in malware analysis.
Bro helps prevent data loss. It ensures compliance with regulations. For example, it can detect unauthorized file transfers,
enhancing overall security posture.
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Advanced Techniques
Custom Scripting
Develop specific threat detection scripts.
SIEM Integration
Connects with security information systems.
Distributed Deployment
Monitors large-scale networks effectively.
Advanced use of Bro involves custom script development. This enables
detection of specific threats. Integration with SIEM systems enhances
alert management. Large organizations deploy Bro in distributed
environments. For example, a custom script can detect brute-force SSH
attacks.
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Pros and Cons
Pros Cons
• Deep Protocol Analysis • Steep Learning Curve
• Highly Customizable • Limited Signature-Based Detection
• Event-Driven Design • Resource Intensive
• Comprehensive Logging • Not a Preventive Tool
• Passive Monitoring • Requires Tuning
Bro IDS offers significant benefits for network security. Its deep analysis and customization are powerful assets. However, it
presents challenges like a steep learning curve. It also requires significant resources and continuous tuning for optimal
performance.
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Conclusion: Leveraging Bro
for Network Security
Powerful Tool
Zeek/Bro offers deep network visibility.
Proactive Detection
Enables threat detection and response.
Expertise Needed
Requires network security knowledge.
Bro, now Zeek, is invaluable for network security. It provides deep
network visibility. This enables proactive threat detection. Optimal use
demands expertise in network security and scripting. Ongoing
development and an active community ensure its continued relevance
and support.
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