binlex

A Genetic Binary Trait Lexer Library and Utility

The purpose of binlex is to extract basic blocks and functions as traits from binaries for malware research, hunting and detection.

Most projects attempting this use Python to generate traits, but it is very slow.

The design philophy behind binlex is it to keep it simple and extensable.

The simple command-line interface allows malware researchers and analysts to hunt traits across hundreds or thousands of potentially similar malware saving time and money in production environments.

While the C++ API allows developers to get creative with their own detection solutions.

Introduction Video

Get slides here.

Use Cases

YARA Signature Creation/Automation
Identifying Code-Reuse
Threat Hunting
Building Goodware Trait Corpus
Building Malware Trait Corpus
Genetic Programming
Machine Learning Malware Detection

Installing

From Source:

Please note that binlex requires cmake >= 3.5 and make >= 4.2.1.

sudo apt install -y git build-essential libcapstone-dev cmake make parallel doxygen git-lfs
git clone --recursive https://github.com/c3rb3ru5d3d53c/binlex.git
cd binlex/
make threads=4
sudo make install
binlex -m elf:x86 -i tests/elf/elf.x86

Binary Release: See the releases page.

NOTE:

ZIP files in the tests/ directory can be extracted using the password infected

Basic Usage

binlex v1.1.0 - A Binary Genetic Traits Lexer
  -i  --input           input file              (required)
  -m  --mode            set mode                (required)
  -lm --list-modes      list modes
  -h  --help            display help
  -o  --output          output file             (optional)
  -p  --pretty          pretty output           (optional)
  -v  --version         display version
Author: @c3rb3ru5d3d53c

Currently Supported Modes

elf:x86
elf:x86_64
pe:x86
pe:x86_64
raw:x86
raw:x86_64
raw:cil (experimental)

NOTE: The raw formats can be used on shellcode

Advanced Usage

If you are hunting using binlex you can use jq to your advantage for advanced searches.

binlex -m raw:x86 -i tests/raw/raw.x86 | jq -r '.[] | select(.type == "block" and .size < 32 and .size > 0) | .bytes'
2c 20 c1 cf 0d 01 c7 49 75 ef
52 57 8b 52 10 8b 42 3c 01 d0 8b 40 78 85 c0 74 4c
01 d0 50 8b 58 20 8b 48 18 01 d3 85 c9 74 3c
49 8b 34 8b 01 d6 31 ff 31 c0 c1 cf 0d ac 01 c7 38 e0 75 f4
03 7d f8 3b 7d 24 75 e0
58 5f 5a 8b 12 e9 80 ff ff ff
ff 4e 08 75 ec
e8 67 00 00 00 6a 00 6a 04 56 57 68 02 d9 c8 5f ff d5 83 f8 00 7e 36
e9 9b ff ff ff
01 c3 29 c6 75 c1

Other queries you can do:

# Block traits with a size between 0 and 32 bytes
jq -r '[.[] | select(.type == "block" and .size < 32 and .size > 0)]'
# Function traits with a cyclomatic complexity greater than 32 (maybe obfuscation)
jq -r '[.[] | select(.type == "function" and .cyclomatic_complexity > 32)]'
# Traits where bytes have high entropy
jq -r '[.[] | select(.bytes_entropy > 7)]'
# Output all trait strings only
jq -r '.[] | .trait'
# Output only trait hashes
jq -r '.[] | .trait_sha256'

If you output just traits you want to stdout you can do build a yara signature on the fly with the included tool blyara:

build/binlex -m raw:x86 -i tests/raw/raw.x86 | jq -r '.[] | select(.size > 16 and .size < 32) | .trait' | build/blyara --name example_0 -m author example -m tlp white -c 1
rule example_0 {
    metadata:
        author = "example"
        tlp = "white"
    strings:
        trait_0 = {52 57 8b 52 ?? 8b 42 ?? 01 d0 8b 40 ?? 85 c0 74 4c}
        trait_1 = {49 8b 34 8b 01 d6 31 ff 31 c0 c1 cf ?? ac 01 c7 38 e0 75 f4}
        trait_2 = {e8 67 00 00 00 6a 00 6a ?? 56 57 68 ?? ?? ?? ?? ff d5 83 f8 00 7e 36}
    condition:
        1 of them
}

You can also use the switch --pretty to output json to identify more properies to query.

binlex -m pe:x86 -i tests/pe/pe.trickbot.x86 --pretty
[
  {
    "average_instructions_per_block": 29,
    "blocks": 1,
    "bytes": "ae 32 c3 32 1a 33 25 34 85 39 ae 3b b4 3b c8 3b 35 3c 3a 3c 6b 3c 71 3c 85 3c aa 3d b0 3d 6a 3e a5 3e b8 3e fd 3e 38 3f 4b 3f 87 3f 00 20 00 00 58 00 00 00 4f 30 aa 30 01 31 1d 31 ac 31 d6 31 e5 31 f5 31 1c 32 31 32 75 34",
    "bytes_entropy": 5.070523738861084,
    "bytes_sha256": "67a966fe573ef678feaea6229271bb374304b418fe63f464b71af1fbe2a87f37",
    "cyclomatic_complexity": 3,
    "edges": 2,
    "instructions": 29,
    "offset": 11589,
    "size": 74,
    "trait": "ae 32 c3 32 1a 33 25 ?? ?? ?? ?? 3b b4 3b ?? ?? ?? ?? 3a 3c 6b 3c 71 3c 85 3c aa 3d b0 3d 6a 3e a5 3e b8 3e fd 3e 38 3f 4b 3f 87 3f 00 20 00 00 58 00 00 00 4f ?? aa 30 01 31 1d ?? ?? ?? ?? 31 e5 31 f5 31 1c 32 31 32 75 34",
    "trait_entropy": 4.9164042472839355,
    "trait_sha256": "a00fcb2b23a916192990665d8a5f53b2adfa74ec98991277e571542aee94c3a5",
    "type": "block"
  }
]

If you have terabytes of executable files, we can leverage the power of parallel to generate traits for us.

make traits source=samples/malware/pe/x32/ dest=dist/ type=malware format=pe arch=x86 threads=4
make traits-combine source=dist/ dest=dist/ type=malware format=pe arch=x86 threads=4

It also allows you to name your type of dataset, i.e. goodware/malware/riskware/pua etc...

With binlex it is up to you to remove goodware traits from your extracted traits.

There have been many questions about removing "library code", there is a make target shown below to help you with this.

make traits-clean remove=goodware.traits source=sample.traits dest=malware.traits

With binlex the power is in your hands, "With great power comes great responsibility", it is up to you!

Plugins:

There has been some interest in making IDA, Ghidra and Cutter plugins for binlex.

This is something that will be started soon.

This README.md will be updated when they are ready to use.

General Usage Information:

Binlex is designed to do one thing and one thing only, extract genetic traits from executable code in files. This means it is up to you "the researcher" / "the data scientist" to determine which traits are good and which traits are bad. To accomplish this, you need to use your own fitness function. I encourage you to read about genetic programming to gain a better understanding of this in practice. Perhaps watching this introductory video will help your understanding.

Again, it's up to you to implement your own algorithms for detection based on the genetic traits you extract.

Trait Format

Traits will contain binary code represented in hexadecimal form and will use ?? as wild cards for memory operands or other operands subject to change.

They will also contain additional properties about the trait including its offset, edges, blocks, cyclomatic_complexity, average_instruction_per_block, bytes, trait, trait_sha256, bytes_sha256, trait_entropy, bytes_entropy, type, size, and instructions.

[
  {
    "average_instructions_per_block": 29,
    "blocks": 1,
    "bytes": "ae 32 c3 32 1a 33 25 34 85 39 ae 3b b4 3b c8 3b 35 3c 3a 3c 6b 3c 71 3c 85 3c aa 3d b0 3d 6a 3e a5 3e b8 3e fd 3e 38 3f 4b 3f 87 3f 00 20 00 00 58 00 00 00 4f 30 aa 30 01 31 1d 31 ac 31 d6 31 e5 31 f5 31 1c 32 31 32 75 34",
    "bytes_entropy": 5.070523738861084,
    "bytes_sha256": "67a966fe573ef678feaea6229271bb374304b418fe63f464b71af1fbe2a87f37",
    "cyclomatic_complexity": 3,
    "edges": 2,
    "instructions": 29,
    "offset": 11589,
    "size": 74,
    "trait": "ae 32 c3 32 1a 33 25 ?? ?? ?? ?? 3b b4 3b ?? ?? ?? ?? 3a 3c 6b 3c 71 3c 85 3c aa 3d b0 3d 6a 3e a5 3e b8 3e fd 3e 38 3f 4b 3f 87 3f 00 20 00 00 58 00 00 00 4f ?? aa 30 01 31 1d ?? ?? ?? ?? 31 e5 31 f5 31 1c 32 31 32 75 34",
    "trait_entropy": 4.9164042472839355,
    "trait_sha256": "a00fcb2b23a916192990665d8a5f53b2adfa74ec98991277e571542aee94c3a5",
    "type": "block"
  }
]

Documentation

Public documentation on binlex can be viewed here.

Building Docs

You can access the C++ API Documentation and everything else by building the documents using doxygen.

make docs threads=4

The documents will be available at build/docs/html/index.html.

C++ API Example Code

It couldn't be any easier to leverage binlex and its C++ API to build your own applications.

See example code below:

#include <binlex/pe.h>
#include <binlex/decompiler.h>

using namespace binlex;

int main(int argc, char **argv){
  Pe pe32;
  if (pe32.Setup(PE_MODE_X86) == false){
      return 1;
  }
  if (pe32.ReadFile(argv[1]) == false){
      return 1;
  }
  Decompiler decompiler;
  decompiler.Setup(CS_ARCH_X86, CS_MODE_32);
  for (int i = 0; i < PE_MAX_SECTIONS; i++){
      if (pe32.sections[i].data != NULL){
          decompiler.x86_64(pe32.sections[i].data, pe32.sections[i].size, pe32.sections[i].offset, i);
      }
  }
  decompiler.PrintTraits(args.options.pretty);
}

We hope this encourages people to build their own detection solutions based on binary genetic traits.

Tips

If you are hunting be sure to use jq to improve your searches
Does not support PE files that are VB6 or .NET if you run against these you will get errors
Don't mix packed and unpacked malware or you will taint your dataset (seen this in academics all the time)
Verify the samples you are collecting into a group using skilled analysts
These traits are best used with a hybrid approach (supervised)

Example Fitness Model

Traits will be compared amongst their common malware family, any traits not common to all samples will be discarded.

Once completed, all remaining traits will be compared to traits from a goodware set, any traits that match the goodware set will be discarded.

To further differ the traits from other malware families, the remaining population will be compared to other malware families, any that match will be discarded.

The remaining population of traits will be unique to the malware family tested and not legitimate binaries or other malware families.

This fitness model allows for accurate classification of the tested malware family.

Future Work

Recursive Decompiler
Java Bytecode Support raw:jvm, java:jvm
Cutter, Ghidra and IDA Plugins
.NET support pe:cil and raw:cil
Mac-O Support macho:x86_64, macho:x86

Contributing

If you wish to contribute to Binlex DM me on Twitter here.

You can also join our Discord here.

Currently looking for help on:

MacOS Developer (Parse Mach-O)
Plugin Developers (Python)

ashr/binlex