Reverse Engineering Flash

Question

I have some Flash SWF files that I need some insight into how they are working. Are they any good tools out there to reverse engineer a SWF file?

Thanks.

Answer 1

Disassemble the SWF with Flasm.

Note: Only works for flash 8 or earlier unfortunately.

SWFTools might give you some information as well about the SWF files. They seem to be much more recent.

Answer 2

I hate to give the "just google it" answer, but it really is that simple if you know what terms to use.

Answer 3

In addition to grabbing a Flash decompiler, you may want to read the SWF File Format Specification docs.

Answer 4

As someone constantly working with SWF file format and ActionScript 2 and 3 bytecode, I highly recommend ASV. Unlike other decompilers, it has been designed to look into SWF files, not just convert them to FLA.

Also, you will need to read the following documents:

SWF File Format Specs v10

AVM2 Overview

Answer 5

FWIW: I have created an ActionScript 3 (dis-)assembler (which allows you to assemble back modified code, even for obfuscated files). It is similar in functionality to flasm, however it targets the AVM (used in newer Flash versions), and works directly with the AS bytecode rather than entire SWF files. To edit the rest of the file, you could use a tool such as SWiX.