VBA static and dynamic analysis tool for malware analysts
Project description
SpuriousEmu
Visual Basic for Applications tools allowing to parse VBA files, interpret them and extract behaviour information for malware analysis purpose.
Usage
SpuriousEmu can work with VBA source files, or directly with Office documents. For the later case, it relies on olevba to extract macros from the files. For each of the commands, use the -i
flag to specify the input file to work with, whatever its format.
If you work with VBA source files, the following convention is used:
- procedural modules have .bas
extension
- class modules have .cls
extension
- standalone script files have .vbs
extension
SpuriousEmu uses different subcommands for its different operating modes.
Static analysis
Static analysis is performed using the static
subcommand.
Usually, the first step is to determine the different functions and classes defined, in order to understand the structure of the program. You can for example use it to determine the entry point prior to dynamic analysis. It is the default behaviour when using no other flag than -i
:
./emu.py static -i document.xlsm
Additionally, for large files, you can use the -o
flag to serialize the information compiled during static analysis into a binary file that you will be able to use later with the -i
flag:
./emu.py static -i document.xlsm -o document.spurious-com
You can also de-obfuscate a file by using the -d
flag, which specifies the de-obfuscation level. You can output the whole file, or a single function or module using the -e
flag. The result can be sent to standard output or written to a file specified with the -o
file:
./emu.py static -i document.xlsm -d3 -e VBAEnv.Default.Main -o Main.bas
Dynamic analysis
You can trigger dynamic analysis with the dynamic
subcommand.
Once you have found the entry-point you want to use with the static
subcommand, you can execute a file by specifying it with the -e
flag. For example, to launch the Main
function found in doc.xlsm
, use
./emu.py dynamic -i doc.xlsm -e Main
This will display a report of the execution of the program. Additionally, if you want to save the files created during execution, you can use the -o
flag: it specifies a directory to save files to. Each created file is then stored in a file with its md5 sum as title, and a {hash}.filename.txt
file contains its original name.
Dependencies
Python 3.8 is used, and SpuriousEmu mainly relies on pyparsing
for VBA grammar parsing, and oletools
to extract VBA macros from Office documents.
nose
is used as testing framework, and mypy
to perform static code analysis. lxml
and coverage
are used to produce test reports.
Tests
To set a development environment up, use poetry
:
poetry install
Then, use nose to run the test suite:
poetry run nosetests
All test files are in tests
, including:
- Python test scripts, starting with test_
- VBA scripts used to test the different stages of the tools, with vbs
extensions, stored in source
- expected test results, stored as JSON dumps in result
You can use mypy to perform code static analysis:
poetry run mypy emu/*.py
Both commands produce HTML reports stored in 'tests/report'.
Project details
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Source Distribution
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Hashes for spurious_emu-0.1.0-py3-none-any.whl
Algorithm | Hash digest | |
---|---|---|
SHA256 | 9ad08fa56fd5e598da695caa0fd8b112669c33ec8f9a8819e3c44b609949c16a |
|
MD5 | c3e4bd58b197dfb04d118cd2cbf7e2a4 |
|
BLAKE2b-256 | 9c6b834a5df9d2b4ea597a08e5ff7d1bd177357dc0394b82484c69d77fcad488 |