Mutation Fuzzing
What is Mutation Fuzzing?
Mutation FuzzingA fuzz testing strategy that derives new test inputs by randomly mutating existing valid samples, such as flipping bits, inserting bytes or splicing files.
Mutation fuzzers start with a corpus of valid inputs — sample images, network packets, documents — and apply small random changes (bit flips, byte substitutions, block deletions, splices) to generate new candidates. Unlike generation-based fuzzers, they do not need a grammar of the input format, which makes them quick to deploy on any parser or protocol. When combined with coverage feedback, mutation fuzzers like AFL++ and libFuzzer can quickly evolve inputs that explore deep code paths and trigger memory-safety bugs. They are widely used to harden codecs, file parsers, kernel drivers and cryptographic libraries during the SSDLC.
● Examples
- 01
AFL++ mutating valid PNG files to discover heap-overflow bugs in libpng.
- 02
libFuzzer mutating valid HTTP requests to crash a custom HTTP parser.
● Frequently asked questions
What is Mutation Fuzzing?
A fuzz testing strategy that derives new test inputs by randomly mutating existing valid samples, such as flipping bits, inserting bytes or splicing files. It belongs to the Application Security category of cybersecurity.
What does Mutation Fuzzing mean?
A fuzz testing strategy that derives new test inputs by randomly mutating existing valid samples, such as flipping bits, inserting bytes or splicing files.
How do you defend against Mutation Fuzzing?
Defences for Mutation Fuzzing typically combine technical controls and operational practices, as detailed in the full definition above.
What are other names for Mutation Fuzzing?
Common alternative names include: Mutational fuzzing, Sample-based fuzzing.