Class File Searcher

Published 07/20/2024

Command-line tool for dumping Class-files & Strings from arbitrary data

What Does It Do?

• Finds & dumps Class-Files / Strings from arbitrary data

Links

• Download
• View Source Code
• Report An Issue

Requirements

• Java 8 or greater

Media

^{(Click to enlarge)}

How To Install

• Download the latest release for your platform
• Add the binary to your system-path
  • Or just call the absolute path to it in the command line

How To Use - Count Class Files (Initial first look)

• cfs count input.bin - Searches for classes inside the file input.bin
• cfs count input-p1.bin input-p2.bin - Searches for classes inside the two files input-p1.bin & input-p2.bin
• cfs count *.bin - Searches for classes in all files in the current path that end in .bin (non-recursive)
• cfs count dir/ - Searches for classes in the specified folder

How To Use - Dump Strings From Found Class Files (Peak what’s inside)

• cfs classes input.bin - Searches for strings from classes inside the file input.bin
• cfs classes input-p1.bin input-p2.bin - Searches for strings from classes inside the two files input-p1.bin & input-p2.bin
• cfs classes *.bin - Searches for strings from classes in all files in the current path that end in .bin (non-recursive)
• cfs classes dir/ - Searches for strings from classes in the specified folder

How To Use - Dump Class Files (Full dive with a decompiler)

• cfs classes input.bin - Searches for classes inside the file input.bin
• cfs classes input-p1.bin input-p2.bin - Searches for classes inside the two files input-p1.bin & input-p2.bin
• cfs classes *.bin - Searches for classes in all files in the current path that end in .bin (non-recursive)
• cfs classes dir/ - Searches for classes in the specified folder

How Does It Work?

• We search for all instances of CAFEBABE and store the data between each file, assuming the files are stored back to back.
• We make the following assumptions:
  • It’s uncompressed data
  • It’s not lying to us when it says CAFEBABE
  • The files are stored back to back, I.E. each chunk of CAFEBABE represents another class once reached.

Notes

• We’re resistant to most obfuscation, but if you find something that breaks CFS feel free to report the issue.

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