☠️ SEMA ☠️

ToolChain using Symbolic Execution for Malware Analysis.

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Toolchain architecture

Our toolchain is represented in the following figure and works as follows:

• A collection of labelled binaries from different malware families is collected and used as the input of the toolchain.
• Angr, a framework for symbolic execution, is used to execute binaries symbolically and extract execution traces. For this purpose, different heuristics have been developed to optimize symbolic execution.
• Several execution traces (i.e., API calls used and their arguments) corresponding to one binary are extracted with Angr and gathered together using several graph heuristics to construct a SCDG.
• These resulting SCDGs are then used as input to graph mining to extract common graphs between SCDGs of the same family and create a signature.
• Finally, when a new sample has to be classified, its SCDG is built and compared with SCDGs of known families using a simple similarity metric.

This repository contains a first version of a SCDG extractor. During the symbolic analysis of a binary, all system calls and their arguments found are recorded. After some stop conditions for symbolic analysis, a graph is built as follows: Nodes are system calls recorded, edges show that some arguments are shared between calls.

When a new sample has to be evaluated, its SCDG is first built as described previously. Then, gspan is applied to extract the biggest common subgraph and a similarity score is evaluated to decide if the graph is considered as part of the family or not. The similarity score S between graph G' and G'' is computed as follows: Since G'' is a subgraph of G', this is calculating how much G' appears in G''. Another classifier we use is the Support Vector Machine (SVM) with INRIA graph kernel or the Weisfeiler-Lehman extension graph kernel.

A web application is available and is called SemaWebApp. It allows to manage the launch of experiments on SemaSCDG and/or SemaClassifier.

Pre-commit

This repository uses pre-commit to ensure that the code is formatted correctly and that the code is clean. To install pre-commit, run the following command:

python3 -m pip install pre-commit
pre-commit install

Documentation

• Complete README of the entire toolchain :

• SCDG README :

• Classifier README :

• Web app README :

• A Makefile is provided to ease the usage of the toolchain, run make help for more information about the available commands

Credentials

Main authors of the projects:

• Charles-Henry Bertrand Van Ouytsel (UCLouvain)

• Christophe Crochet (UCLouvain)

• Khanh Huu The Dam (UCLouvain)

• Oreins Manon (UCLouvain)

Under the supervision and with the support of Fabrizio Biondi (Avast)

Under the supervision and with the support of our professor Axel Legay (UCLouvain) (:heart:)

Linked papers

• Analysis and classification of malware based on symbolic execution and machine learning

• Tool Paper - SEMA: Symbolic Execution Toolchain for Malware Analysis

• On Exploiting Symbolic Execution to Improve the Analysis of RAT Samples with angr