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Intermediate Topic 27 of 51 Security & Cryptography

Buffer Overflow

Writing past a buffer's end to corrupt memory.

How it works

Writing beyond an array's bounds in C/C++ overwrites adjacent memory, such as a return address, enabling code execution. Mitigations: bounds checking, stack canaries, ASLR, DEP/NX and memory-safe languages.

Where it is used

Classic exploit class.

Common pitfall

strcpy, gets and unchecked memcpy are red flags.

Where it fits in the course

Buffer Overflow is topic 27 of 51 in Security & Cryptography, rated Intermediate. It follows CSRF. The next topic is Denial of Service.

Practice and explore

How to study this topic

  1. Read the explanation above and restate the definition in your own words.
  2. Open the interactive lesson and answer its mini quiz.
  3. Read the common pitfall, then write a short example that avoids it.
  4. Check your understanding in the Security & Cryptography quiz, and revisit the topic if you miss a question.

Frequently asked questions

What is Buffer Overflow?
Writing past a buffer's end to corrupt memory. It belongs to Security & Cryptography and is an intermediate-level topic.
Where do people use Buffer Overflow?
Classic exploit class.
What is the most common mistake with Buffer Overflow?
strcpy, gets and unchecked memcpy are red flags.
What should I learn before this topic?
Start with CSRF, the topic just before it in Security & Cryptography.
How can I practice it?
Answer the mini quiz in the interactive lesson, then take the Security & Cryptography quiz.
Is Buffer Overflow hard to learn?
It is an Intermediate topic. Be comfortable with the Beginner topics in this area first, then read the common pitfall carefully, since it is where most mistakes happen.
How long does it take to learn Buffer Overflow?
Most learners can read the explanation and finish the interactive lesson in under an hour. Fluency comes from applying the idea, so plan a few short practice sessions with the quiz.
Which topics are related to Buffer Overflow?
CSRF, Denial of Service, Cross-Site Scripting are closely connected. The full list is in the related topics section of this page.
What should I study after Buffer Overflow?
Continue with Denial of Service, the next topic in Security & Cryptography.

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