VoIP Security and Hacking

VoIP Security and Hacking is a specialized domain of cybersecurity focused on protecting Voice over Internet Protocol communication systems from malicious attacks and unauthorized access. This field addresses a range of threats that exploit vulnerabilities in VoIP protocols like SIP and RTP, including eavesdropping on calls, toll fraud (making unauthorized calls billed to the victim), Denial-of-Service (DoS) attacks to disrupt communication, and vishing (voice phishing) via caller ID spoofing. To counter these risks, security professionals implement a layered defense strategy that includes encrypting call signaling and media streams using TLS and SRTP, deploying VoIP-aware firewalls, enforcing strong authentication, and segmenting network traffic to ensure the confidentiality, integrity, and availability of voice communications.

1. Introduction to VoIP Technology
   1. Fundamentals of Voice over IP
      1. Analog vs. Digital Voice
         1. Characteristics of Analog Voice Transmission
         2. Digital Voice Encoding and Decoding
         3. Analog-to-Digital Conversion Process
         4. Sampling Rate and Bit Depth
         5. Quantization and Compression
      2. Packet Switching vs. Circuit Switching
         1. Principles of Circuit Switching
         2. Principles of Packet Switching
         3. Comparison of Packet and Circuit Switching for Voice
         4. Advantages and Disadvantages of Each Method
      3. Core Concepts of VoIP
         1. Voice Sampling and Codec Selection
         2. Packetization of Voice Data
         3. Jitter, Latency, and Packet Loss
         4. Quality of Service (QoS) Considerations
         5. Echo and Echo Cancellation
         6. Voice Activity Detection (VAD)
   2. Key VoIP Protocols and Standards
      1. Signaling Protocols
         1. Session Initiation Protocol (SIP)
            1. SIP Message Types
            2. SIP Call Flow
            3. SIP URI Structure
            4. SIP Headers and Methods
            5. SIP Response Codes
            6. SIP Proxy and Registrar Functions
         2. H.323
            1. H.323 Components
            2. H.323 Call Setup Process
            3. H.225 and H.245 Protocols
            4. H.323 Gatekeeper Functions
         3. Media Gateway Control Protocol (MGCP)
            1. MGCP Architecture
            2. MGCP Call Control
            3. MGCP Commands and Responses
         4. Skinny Client Control Protocol (SCCP)
            1. SCCP Overview
            2. SCCP Use Cases
            3. SCCP Message Structure
      2. Media Transport Protocols
         1. Real-time Transport Protocol (RTP)
            1. RTP Packet Structure
            2. RTP Sequence and Timing
            3. RTP Payload Types
            4. RTP Synchronization
         2. Real-time Transport Control Protocol (RTCP)
            1. RTCP Functions
            2. RTCP Reporting
            3. RTCP Packet Types
            4. Quality Feedback Mechanisms
      3. Supporting Protocols
         1. Session Description Protocol (SDP)
            1. SDP Message Structure
            2. SDP in Call Negotiation
            3. Media Description Lines
            4. Attribute Lines
         2. Domain Name System (DNS) for VoIP
            1. SRV Records for Service Discovery
            2. ENUM for Number Mapping
            3. NAPTR Records
   3. VoIP Call Flow and Lifecycle
      1. Call Initiation and Setup
         1. User Registration
         2. Call Signaling Exchange
         3. Authentication Process
         4. Address Resolution
      2. Media Session Establishment
         1. Codec Negotiation
         2. NAT Traversal Techniques
         3. ICE (Interactive Connectivity Establishment)
         4. STUN and TURN Protocols
      3. Call Maintenance
         1. Call Hold and Transfer
         2. DTMF Signaling
         3. Call Quality Monitoring
         4. Mid-call Modifications
      4. Call Termination
         1. Call Teardown Signaling
         2. Resource Release
         3. Call Detail Records (CDR)