FLOSS¶
What FLOSS does¶
Using this tool
FLOSS supports malware analysis. In this guide, you will use it to recover decoded strings from a known training executable and prioritise useful leads. Follow the steps below and keep the output with your notes.
Tool guide at a glance¶
Recover decoded strings from a known training executable and prioritise useful leads.
An inert or purpose built training sample stored in a disposable isolated analysis VM.
A static observation or capability finding with sample hash, tool output, and confidence statement.
Evidence and safety
Do not execute unknown samples on SUSA. Disable shared folders and credentials, and use only authorised training material. Record the input identifier, tool version, relevant commands or settings, time and time zone, output location, and any errors or limitations as you work.
Choose your journey¶
01Understand the evidenceLearn the malware analysis concepts and limitations.Complete when you can explain what the evidence can and cannot show.Beginner · No tool required 02Follow the FLOSS guideFollow the steps and screenshots below.Complete when the documented workflow produces its expected output.Guided · SUSA workstation · Time varies 03Interactive labPractise the tool workflow in a safe browser simulation.Complete when the guided result is supported by the case evidence.Beginner · Browser only 04Full LabUse your own training data, keep the output and explain what you found.Complete when another analyst can reproduce and verify the outcome.Intermediate · Isolated lab
How the labs complement this guide
The Interactive Lab uses example records to practise investigation decisions. It does not run the installed tool or establish how that version behaves. The Full Lab uses your own training environment and evidence. Obtain or create the required input before starting; a case name in an exercise is not a download.
Accessing FLOSS in SUSA¶
The FLARE Obfuscated String Solver (FLOSS, formerly FireEye Labs Obfuscated String Solver) uses advanced static analysis techniques to automatically extract and deobfuscate all strings from malware binaries. You can use it just like strings.exe to enhance the basic static analysis of unknown binaries.
Download the latest stable FLOSS binary from the official release page.
Extract the ZIP archive to the C:\Tools\FLOSS directory.
Adding FLOSS to PATH environment variable¶
Open Environment Variables (Start → Environment Variables → Edit the system environment variables → Environment Variables).
Under User variables, select path and click Edit.
Click New and add (one entry per line):
Click OK (then OK on other windows to save changes).
Testing FLOSS¶
Open an administrator Command Prompt and run FLOSS against notepad.exe: