MalNetLib
MalNetLib is a Python library for parsing PE files made with .NET (based on dnlib).
Installation
Install the library (available on pypi.org):
$ python3 -m pip install malnetlibCompile dnlib.dll (required for the project) :
# Debian
$ sudo apt install -y dotnet-sdk-6.0
# Arch
$ sudo pacman -S dotnet-sdk-6.0
$ git clone --depth=1 https://github.com/0xd4d/dnlib
$ cd dnlib
$ dotnet build
$ cd ..
$ cp ./dnlib/Examples/bin/Debug/net6.0/dnlib.dll .
$ rm -rf dnlibExamples
NjRAT
NjRAT is a remote access trojan (RAT).
You can use malnetlib to extract the configuration of NjRAT which is stored inside .NET class attributes. Here is an example with the a sample of NjRAT and the script njrat_extractor.py :
pe = DotNetPE(args.sample)
ok_class = pe.get_object("OK")
njrat_conf = {
"host": ok_class.get_attribute("HH").get_value(),
"port": ok_class.get_attribute("P").get_value(),
"install_directory": "%" + ok_class.get_attribute("DR").get_value() + "%",
"install_name": ok_class.get_attribute("EXE").get_value(),
"startup": ok_class.get_attribute("sf").get_value(),
"campain_id": b64decode(ok_class.get_attribute("VN").get_value()).decode("UTF-8"),
"version": ok_class.get_attribute("VR").get_value(),
"network_separator": ok_class.get_attribute("Y").get_value(),
"mutex": ok_class.get_attribute("RG").get_value()
}
print(dumps(njrat_conf)){
"host": "2.tcp.eu.ngrok.io",
"port": "10008",
"install_directory": "%TEMP%",
"install_name": "server.exe",
"startup": "Software\\Microsoft\\Windows\\CurrentVersion\\Run",
"campain_id": "HacKed",
"version": "im523",
"network_separator": "|'|'|",
"mutex": "25ffb1a66b4748fe7537df7005cc8e55"
}vw0rm
VJW0rm (aka Vengeance Justice Worm) is a publicly available, modular JavaScript RAT. Other variants include a Visual Basic Script (VBS) based worm titled vw0rm (Vengeance Worm).
You can use malnetlib to list and extract .NET resources from a vw0rm dropper.
>>> from malnetlib.models import DotNetPE
>>> pe = DotNetPE("30d64daeb3e69ea6dde202a9d519f6ee17614af6e505dd2e5788017c3be4abd8")
>>> resources = pe.get_resources()
>>> resources
[<Resource Windows_Task_Manager.Resources.resources 0x0>, <Resource Windows_Task_Manager.proccesing.resources 0x4806>]
>>> resources[0].save("/tmp/output.bin")>>> resources[0].read()
b'[...]On error resume next\r\n\r\nj = array("WScript.Shell","Scripting.FileSystemObject","Shell.Application","Microsoft.XMLHTTP")
\r\ng = array("HKCU","HKLM","HKCU\\vw0rm","\\Software\\Microsoft\\Windows\\CurrentVersion\\Run\\","HKLM\\SOFTWARE\\Classes\\","REG_SZ","\\defaulticon\\")\r\ny=
array("winmgmts:","win32_logicaldisk","Win32_OperatingSystem","winmgmts:\\\\localhost\\root\\securitycenter","AntiVirusProduct")\r\n\r\nfunction go(m)\r\n
