File Fuzzer

By Peter O. – Public Domain – http://peteroupc.github.io/Fuzzer

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This is a program that generates slightly altered versions of data files, for testing algorithms that parse file formats. It’s a command line utility.

Usage: Fuzzer.exe [fuzzer-xml]

fuzzer-xml is an XML file specifying configuration data. If not given, the fuzzer will read the file fuzzer.xml. It has the following XML format:

<fuzzer>
 <outputPath></outputPath>
 <validFilesPath></validFilesPath>
 <validFilesPattern></validFilesPattern>
 <startBytes></startBytes>
 <fileExtension></fileExtension>
 <fuzzOffset></fuzzOffset>
 <frequencyMean></frequencyMean>
 <frequencyStdDev></frequencyStdDev>
 <iterations></iterations>
</fuzzer>

• outputPath - Path of the directory to store the generated file.
• validFilesPath - Path of the directory containing files in a particular file format. The fuzzer will randomly manipulate these files to generate its test data.
• startBytes - A hexadecimal string specifying the bytes to write at the beginning of some of the generated files. Such files will contain random data following the header.
• fileExtension - File extension of the generated files.
• fuzzOffset - Byte offset of the point where the fuzzer will modify the bytes of the files located in validFilesPath.
• frequencyMean - Mean of the frequency of changes, in bytes.
• frequencyStdDev - Standard deviation of the frequency of changes, in bytes.
• iterations - Number of files to generate. Each file will be named XXXXX.YYY where XXXXX is a sequence of five or more digits and YYY is the file extension given in fileExtension.