DC3-Kordesii is a framework for decoding encoded strings and files in malware via IDA Pro IDAPython scripting. One parser module is usually created per malware family. It is designed to ease the burden of encoded string extraction by doing it in an automated, static way as well as to provide a standard set of functionality and methodologies. It supports both an analyst directed analysis and large-scale automated executing, utilizing either the REST API, the CLI or by manually running decoders in IDA.
DC3-Kordesii is authored by the Department of Defense Cyber Crime Center (DC3).
DC3-Kordesii requires the following:
- python 2.7 (32 bit)
- IDA Pro 7.* (tested with 7.0)
- (optional) Hex Ray's Decompiler for x86/x64 architectures
- (Used to improve accuracy of getting function arguments in
function_tracing)
- (Used to improve accuracy of getting function arguments in
> pip install kordesiiAlternatively you can clone this repo and install locally.
> git clone https://github.com/Defense-Cyber-Crime-Center/kordesii.git
> pip install ./kordesiiFor a development mode use the -e flag to install in editable mode:
> git clone https://github.com/Defense-Cyber-Crime-Center/kordesii.git
> pip install -e ./kordesiiBy default kordesii assumes you are on Windows and have installed IDA under the default location C:/Program Files/IDA Pro *.
If you have installed IDA at a different location or running on another operating system, please set the IDA_DIR environment
to point to where IDA has been installed.
DC3-Kordesii is designed to standardize automation of a task typically done by one-off scripts. Most automated processing systems will use a condition, such as a YARA signature match, to trigger execution of a particular DC3-Kordesii decoder.
There are 2 options for integration of DC3-Kordesii:
- CLI:
kordesii - REST API:
kordesii serve
The kordesii tool provides functionality to run and test decoders on files:
> kordesii parse Sample ./kordesii/decoders/tests/strings.exe
[+] (kordesii): Parsing: ./kordesii/decoders/tests/strings.exe
[+] (kordesii.core): IDA return code = 0
----Decoded Strings----
Hello World!
Test string with key 0x02
The quick brown fox jumps over the lazy dog.
Oak is strong and also gives shade.
Acid burns holes in wool cloth.
Cats and dogs each hate the other.
Open the crate but don't break the glass.
There the flood mark is ten inches.
1234567890
CreateProcessA
StrCat
ASP.NET
kdjsfjf0j24r0j240r2j09j222
32897412389471982470
The past will look brighter tomorrow.
Cars and busses stalled in sand drifts.
The jacket hung on the back of the wide chair.
32908741328907498134712304814879837483274809123748913251236598123056231895712
----Debug----
[+] IDA return code = 0
> kordesii test Sample
Running test cases. May take a while...
1/1 - kordesii:Sample strings.exe 8.9183s
Test stats:
Top 10 Slowest Test Cases:
1. kordesii:Sample strings.exe 8.9183s
Top 10 Fastest Test Cases:
1. kordesii:Sample strings.exe 8.9183s
Mean Running Time: 8.9183s
Median Running Time: 8.9183s
Cumulative Running Time: 0:00:08.918259
Total Running Time: 0:00:09.480942
All Passed = Truesee kordesii -h for full set of options
The REST API provides two commonly used functions:
/run_decoder/<decoder>-- executes a decoder on uploaded file/descriptions-- provides list of available parsers
To use, first start the server by running:
> kordesii serveThe following curl commands demonstrate how to use this web service:
> curl --form data=@README.md http://localhost:8080/run_decoder/foo
> curl http://localhost:8080/descriptionsA simple HTML interface is also available at the same address. Individual samples can be submitted and results saved as JSON, plain text, or ZIP archives.
DC3-Kordesii uses Python's builtin in logging module to log all messages.
By default, logging is configured using the log_config.yml configuration
file. Which is currently set to log all messages to the console and error messages to %LOCALAPPDATA%/kordesii/errors.log.
You can provide your own custom log configuration file by adding the path
to the environment variable KORDESII_LOG_CFG. (Please see Python's documentation for more information on how to write your own configuration file.)
You may also use the --verbose or --debug flags to adjust the logging level when using the kordesii tool.
DC3-Kordesii includes an experimental tracing utility called function_tracing that can be used to statically emulate
and trace instructions within a function.
Please see the CPU Emulation documentation for more information.
DC3-Kordesii includes an experimental utility that can be used to run IDAPython commands remotely from another Python interpreter. This is accomplished by hooking IDA imports with proxy wrapper using Pyro4.
WARNING: This feature is intended to be used in one-off scripts during analysis. It is not recommended for this feature to be used in production code.
To install, you'll need Pyro4 and dill installed in IDA's python folder. However, these can be installed somewhere else, as long as it is discoverable within IDA's interpreter.
> pip install Pyro4 dill --target=%IDA_DIR%\pythonTo use, pass the file path you want to analyze to kordesii.IDA() in a with statement.
Within this statement, you can now import and use IDA modules like normal.
import kordesii
with kordesii.IDA(r'C:/data.exe'):
import idc
mnem = idc.print_insn_mnem(0x00401525) For a more interactive experience, you can also start and stop the proxy manually.
>>> import kordesii
>>> ida = kordesii.IDA(r'C:/data.exe')
>>> ida.start()
>>> import idc
>>> idc.print_insn_mnem(0x00401525)
'push'
>>> ida.stop()NOTE: This proxy is only limited to functions that can return serializable objects. Therefore, any function
that returns a PySwigObject object will not work. (e.g. func_t).
As a workaround, you can decorate a function using kordesii.run_in_ida to ensure the full function gets executed from within the IDA interpreter. This functions should not accept or return any non serializable
objects or be bounded to a class that could contain one. As well, globals are not transferred over, so
this function should not read or modify them.
import kordesii
@kordesii.run_in_ida
def func_contains(func_ea, target_ea):
import ida_funcs
func = ida_funcs.get_func(func_ea) # can't call directly in IDA proxy due to Swig object!
return func.contains(target_ea)
with kordesii.IDA(r'C:/data.exe'):
print(func_contains(0x004014F5, 0x00401525))(This is also useful to help speed up a procedure that would otherwise be extremely slow due to the large number of proxy calls.)