SYN Flooding Attack (Denial of Service)

Duration: 3 min

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  1. About Course: About the Course
  2. Paper 1 | General Studies: State Wise GK
  3. Paper 1 | Information and Communication Technology: Role of Internet and Web Services, Security in Mobile and Wireless Computing
  4. Paper 1 | Current Affairs: GK- Current Affairs
  5. Paper 2 | Discrete Mathematical Structure: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic, Probability
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  12. Paper 2 | Theory Of Computation: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Moore & Mealy Machines, Pushdown Automata & CFG, Turing Machines, Complexity Theory
  13. Paper 2 | Compiler Design: Intro to Compilers, Lexical Analysis, Grammar & CFG, Syntax Analysis: Top-Down, Syntax Analysis: Bottom-Up, Semantic Analysis & SDT, Intermediate Code Gen, Code Optimization, Run Time Environment
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  15. Paper 2 | Computer Network And Information Security: Introduction to CN, Data Communication, Application Layer, Hardware basics, Cyber Threats and Malware Attacks, Network Security, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP
  16. Paper 2 | Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  17. Paper 2 | Current Trends & Technologies: Emerging Tech Trends, Approaches to AI, Search Algorithms, Game Playing, Knowledge Representation, Planning, Multi Agent Systems, Fuzzy Sets, Natural Language Processing, Artificial Neural Networks, Genetic Algorithms, Artificial Intelligence, Data Warehousing & Mining, Electronic Data Interchange and E-Commerce, Terms & Abbreviations
  18. Paper 2 | Full Length Mock Tests:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This lecture explains the SYN flooding attack as a denial-of-service technique. The presenter uses two diagrams to show how an attacker sends many SYN packets with spoofed source IP addresses to a victim server. The server allocates resources and creates Transmission Control Block (TCB) entries while waiting for the final ACK, but these SYN-ACK replies are lost or never completed. As the half-open connection table fills up, legitimate visitors cannot connect because resources are exhausted.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The slide titled "SYN Flooding Attack(Denial of Service)" introduces the attack with three bullets. The first diagram shows a red Attacker icon sending multiple arrows to a server, while a green Visitor arrow is stopped by a red X labeled "Connections exhausted." The server block lists four rows of "Open port Waiting for ACK:" to illustrate half-open connections. At 25s, the presenter adds a hand-drawn blue arrow over the red arrows to emphasize the flood direction. The bullets explain that attackers fake source IP addresses in datagrams, causing the server to build TCB tables and set timers for connections that will never complete.

  2. 2:00 – 3:00 02:00-03:00

    The presentation transitions to a second diagram labeling an "Attacker host" and a "Victim host." Arrows are explicitly labeled "SYN packets with spoofed source IP addresses" moving from attacker to victim, while returning arrows are labeled "SYN-ACK packets with spoofed destination IP addresses." A cylinder graphic is captioned "The memory buffer in the victim host begins filling up," and crossed-out arrows marked "ACK packets" show that the third handshake step never arrives. The final bullet states, "SYN flooding attack belongs to denial of service attack," confirming the classification. The presenter gestures throughout, emphasizing how the server waits for the third leg of handshaking and allocates unused resources until it runs out.

The core concept is that SYN flooding exploits the three-way TCP handshake by initiating many connections but never completing them. The attacker spoofs source IP addresses so that SYN-ACK replies are sent to non-existent hosts, leaving the victim server stuck in a half-open state. Each pending connection consumes memory and table entries (TCBs), eventually exhausting the server's capacity to accept new legitimate connections. The visual progression from a generic attacker-server diagram to a labeled host-to-host sequence reinforces the mechanism: spoofed SYNs in, lost SYN-ACKs out, no ACKs returned, and a filling memory buffer. This is a classic resource-exhaustion denial-of-service attack.

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