Technical Flashcards
What is a Proxy?
PROXIES
A proxy is an intermediary server that acts as a gateway between a client and a server .
It forwards requests from the client to the server and sends the server’s responses back to the client.
Proxies serve various purposes, such as enhancing security, improving browsing performance, enabling anonymity, and bypassing restrictions.
They can operate at different layers of the OSI model, typically at the application layer.
What are the types of proxies and their uses?
PROXIES
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Forward Proxy:
- Description: Acts as an intermediary between the client and the internet. The client sends requests to the proxy, which forwards them to the desired server.
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Key Characteristics:
- Typically configured on the client side.
- Can filter traffic and enforce access policies.
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Reverse Proxy:
- Description: Sits in front of servers and manages client requests on behalf of the server.
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Key Characteristics:
- Typically configured on the server side.
- Often used in conjunction with load balancers.
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Transparent Proxy:
- Description: Intercepts client requests without requiring client configuration. The client’s IP address is visible to the destination server.
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Key Characteristics:
- Easy to implement in networks.
- Provides minimal privacy protection.
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Anonymous Proxy:
- Description: Hides the client’s IP address but identifies itself as a proxy.
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Key Characteristics:
- Provides basic privacy.
- Still detectable as a proxy by destination servers.
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Elite (High-Anonymity) Proxy:
- Description: Hides both the client’s IP address and the fact that a proxy is being used.
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Key Characteristics:
- Offers the highest level of anonymity.
- Hard to detect.
Key aspects of a reverse proxy
PROXIES
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Load Balancing:
- Function: Distributes incoming client requests across multiple backend servers.
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Benefits:
- Optimizes resource usage.
- Ensures even distribution of traffic.
- Improves system performance and availability.
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Security:
- Function: Acts as an additional security layer between clients and backend servers.
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Benefits:
- Protects backend servers from direct exposure to the internet.
- Supports features like access control, authentication, and protection against web attacks (e.g., SQL injection).
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SSL Termination:
- Function: Handles SSL/TLS encryption and decryption.
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Benefits:
- Reduces the computational load on backend servers.
- Simplifies SSL certificate management.
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Content Caching:
- Function: Stores static content like images, JavaScript, or CSS files.
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Benefits:
- Reduces the load on backend servers.
- Improves response times for end users.
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Application Firewall (WAF):
- Function: Protects against common web-based attacks.
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Benefits:
- Defends against SQL injection, cross-site scripting (XSS), and other vulnerabilities.
- Monitors and filters HTTP traffic to ensure security.
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Compression:
- Function: Compresses data before sending it to clients.
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Benefits:
- Reduces bandwidth usage.
- Improves page load times for users with slower internet connections.
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Logging and Monitoring:
- Function: Provides detailed logs and real-time monitoring of traffic.
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Benefits:
- Tracks traffic patterns and potential issues.
- Monitors backend server performance.
- Assists in troubleshooting and maintaining system health.
Description
IDS / IPS
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IDS (Intrusion Detection System):
- A system designed to monitor network or system activity for suspicious behavior or known threats.
- It alerts administrators of potential security incidents but does not take direct action to stop them.
- Placed out-of-band to monitor mirrored traffic from network devices (e.g., via SPAN ports).
- Ideal for monitoring without disrupting traffic.
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IPS (Intrusion Prevention System):
- Similar to IDS but actively prevents or blocks detected threats.
- It intercepts malicious traffic in real-time, acting as a security barrier.
- Placed in-line, directly inspecting and controlling traffic flow.
- Positioned between the firewall and internal network for real-time protection.
What are the key differences between IDS and IPS?
IDS / IPS
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Action:
- IDS: Detects and alerts.
- IPS: Detects and blocks.
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Placement in Network:
- IDS: Monitors traffic passively (out-of-band).
- IPS: Actively inspects and modifies traffic (in-line).
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Impact on Traffic:
- IDS: Does not affect traffic flow.
- IPS: May introduce latency due to in-line processing.
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Use Case:
- IDS: Forensic analysis and monitoring.
- IPS: Real-time threat prevention.
How does an Intrusion Detection System (IDS) work?
IDS / IPS
- Traffic Monitoring: Observes network or host activity.
- Signature-Based Detection: Compares traffic patterns against a database of known threat signatures.
- Anomaly-Based Detection: Identifies deviations from normal behavior to detect unknown threats.
- Alerting: Generates alerts for suspicious activity, allowing security teams to investigate further.
How does an Intrusion Prevention System (IPS) work?
IDS / IPS
- Traffic Analysis: Analyzes incoming traffic in real-time.
- Threat Detection: Uses the same methods as IDS (signature- and anomaly-based).
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Threat Prevention: Takes proactive actions, such as:
- Dropping malicious packets.
- Blocking IP addresses or connections.
- Modifying traffic to neutralize threats.
What detection methods are used in IDS and IPS?
IDS / IPS
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Signature-Based Detection:
- Matches patterns against a database of known attack signatures.
- Pros: Accurate for known threats.
- Cons: Ineffective against zero-day attacks.
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Anomaly-Based Detection:
- Detects deviations from established baselines of normal behavior.
- Pros: Identifies unknown threats.
- Cons: High false positive rates.
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Behavior-Based Detection:
- Tracks user or system behavior to identify suspicious activity.
- Pros: Adapts to dynamic environments.
- Cons: May require extensive training data.
What is Endpoint Detection and Response (EDR)?
EDR/XDR
Endpoint Detection and Response (EDR) is a cybersecurity solution focused on monitoring, detecting, and responding to threats on individual devices or endpoints.
It collects and analyzes endpoint data in real time to identify suspicious activity and enables quick response to mitigate potential risks.
What are the key features of EDR?
EDR/XDR
- Continuous Monitoring: Collects real-time data from endpoints.
- Threat Detection: Uses behavior analysis and machine learning to identify malicious activity.
- Incident Response: Automates responses such as isolating infected endpoints.
- Data Forensics: Provides detailed insights into the timeline and scope of attacks.
- Integration: Works alongside other security tools like antivirus and firewalls.
What is Extended Detection and Response (XDR)?
EDR/XDR
Extended Detection and Response (XDR) is a security solution that integrates and correlates data from multiple security layers (e.g., endpoints, network, servers, cloud) to provide a unified view of threats.
It expands beyond EDR by covering a broader range of attack vectors and streamlining threat detection and response.
What are the key features of XDR?
EDR/XDR
- Unified Threat Detection: Correlates data across endpoints, network, and cloud.
- Advanced Analytics: Uses AI and machine learning for deeper threat insights.
- Centralized Dashboard: Offers a single pane of glass for managing and analyzing threats.
- Automated Response: Streamlines incident response across multiple layers of the environment.
- Improved Visibility: Provides a holistic view of the security posture.
What are the differences between EDR and XDR?
EDR/XDR
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Scope:
- EDR: Focuses on individual endpoints.
- XDR: Covers endpoints, network, cloud, and more.
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Data Correlation:
- EDR: Limited to endpoint data.
- XDR: Correlates data across multiple layers for deeper insights.
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Threat Detection:
- EDR: Endpoint-specific detection and response.
- XDR: Detects threats across the entire environment.
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Visibility:
- EDR: Narrow, endpoint-focused visibility.
- XDR: Broad, integrated visibility across all security domains.
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Use Case:
- EDR: Best for endpoint-centric organizations.
- XDR: Ideal for organizations seeking holistic threat detection and response.
TCP/UDP
What is TCP (Transmission Control Protocol)?
What are common use cases for TCP?
TCP/UDP
TCP is a connection-oriented protocol that ensures reliable communication between devices over a network. It uses a handshake mechanism to establish a connection and guarantees data delivery in the correct order.
Key Features:
- Reliable communication.
- Error checking and correction.
- Ensures data arrives in sequence.
- Slower due to overhead from connection setup and error checking.
Use Cases
- Web Browsing: HTTP/HTTPS relies on TCP for reliable page loading.
- File Transfers: Protocols like FTP use TCP to ensure files arrive intact.
- Email: SMTP, IMAP, and POP3 use TCP for reliable message delivery.
- Remote Access: SSH and Telnet depend on TCP for secure and ordered communication.
What is UDP (User Datagram Protocol)?
What are common use cases for UDP?
TCP/UDP
UDP is a connectionless protocol that allows fast communication without guaranteeing reliability or delivery order. It sends data as independent packets (datagrams) without establishing a connection.
Key Features:
- Faster but less reliable.
- No error correction.
- No guarantee of delivery order.
- Useful for real-time applications like streaming.
Use Cases UDP
- Streaming: Video (e.g., YouTube, Netflix) and audio (e.g., Spotify) streaming.
- Gaming: Multiplayer games use UDP for real-time responsiveness.
- VoIP: Applications like Skype or Zoom prioritize speed over reliability.
- DNS Queries: DNS uses UDP for quick resolution of domain names to IP addresses.
- Broadcasting: Sending data to multiple devices (e.g., live video feeds).
What are the differences between TCP and UDP?
TCP/UDP
What is a Firewall?
FIREWALLS
A firewall is a network security device or software that monitors and controls incoming and outgoing traffic based on predefined security rules.
Its primary purpose is to establish a barrier between a trusted internal network and untrusted external networks, such as the internet, to protect against unauthorized access and cyber threats.
What are the types of firewalls?
FIREWALLS
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Packet-Filtering Firewall:
- Examines packets based on source/destination IP, ports, and protocols.
- Operates at the network layer (OSI Layer 3).
- Fast but limited in functionality (no deep inspection).
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Stateful Inspection Firewall:
- Tracks the state of active connections.
- Operates at the transport layer (OSI Layer 4).
- More secure than packet filtering but resource-intensive.
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Application-Layer Firewall (Proxy Firewall):
- Filters traffic at the application layer (OSI Layer 7).
- Can inspect data within the traffic (e.g., HTTP requests).
- Slower but offers advanced security features.
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Next-Generation Firewall (NGFW):
- Combines traditional firewall functions with advanced capabilities like deep packet inspection, intrusion prevention, and application awareness.
- Operates across multiple OSI layers.
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Cloud-Based Firewall (Firewall as a Service):
- Hosted in the cloud to secure cloud-based infrastructures.
- Scalable and flexible for remote workforces and cloud environments.
What are the primary functions of a firewall?
FIREWALLS
- Traffic Monitoring and Control: Firewalls analyze network traffic in real time, allowing or blocking packets based on predefined rules.
- VPN Support: Secures remote connections through Virtual Private Networks.
- Perimeter Security: They act as the first line of defense between internal and external networks, preventing unauthorized access.
- Threat Defense: Firewalls protect against attacks such as DoS/DDoS, intrusion attempts, and malware.
- Policy Management: They allow the configuration of detailed security policies, such as access restrictions based on IP addresses, ports, or specific applications.
- Logging and Auditing: Firewalls generate detailed logs of activities, useful for audits and forensic analysis in case of security incidents.
- Adaptability: Modern firewalls use advanced techniques like deep packet inspection and machine learning to enhance threat detection.
What makes a firewall “next-generation”?
FIREWALLS
- Deep Packet Inspection (DPI): Examines the content of packets beyond headers.
- Application Awareness: Identifies and controls traffic based on the application, not just port or protocol.
- Intrusion Prevention (IPS): Actively blocks detected threats.
- Threat Intelligence Integration: Uses real-time data to recognize and block new threats.
- Encrypted Traffic Inspection: Analyzes encrypted traffic (e.g., SSL/TLS).
What is a Domain Generation Algorithm (DGA)?
DOMAIN GENERATION ALGORITHMS (DGA)
A Domain Generation Algorithm (DGA) is a technique used by malware to generate a large number of domain names in a pseudo-random or algorithmic manner.
These domains are used to establish communication between the infected device and its Command-and-Control server, helping attackers evade detection and domain blacklisting.
Why do attackers use DGAs in malware?
DOMAIN GENERATION ALGORITHMS (DGA)
- Avoid Detection: Generated domains are unpredictable and make it difficult for defenders to preemptively block C2 communication.
- Resilience: If one domain is blocked or taken down, the malware can switch to another generated domain.
- Dynamic Infrastructure: Attackers can rotate C2 domains quickly, making it hard for security tools to track.
- Scale: DGAs can generate thousands of domains daily, overwhelming traditional domain monitoring systems.
What are the indicators of DGA-generated domains?
DOMAIN GENERATION ALGORITHMS (DGA)
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Unusual Domain Names: Long, nonsensical, or randomized strings.
- Example:
sdf23tr4d56g.com
- Example:
- High Domain Volumes: Large numbers of unique domains queried in a short time.
- Failed DNS Resolutions: Many queries return NXDOMAIN (non-existent domain) responses.
- Non-Human Patterns: Queries to domains with no apparent user activity or intent.
How can DGA-based threats be mitigated?
DOMAIN GENERATION ALGORITHMS (DGA)
- DNS Traffic Analysis: Monitor DNS queries for signs of DGA activity (e.g., high volumes of failed resolutions).
- Machine Learning Models: Use AI to detect patterns associated with DGA-generated domains.
- Sinkholing: Pre-register or block DGA-predicted domains to disrupt malware communication.
- Threat Intelligence Feeds: Use updated threat feeds to identify known DGA patterns.
- Endpoint Protection: Deploy security solutions that detect and block malware attempting to use DGAs.