Marx

Uncovering Class Hierarchies in C++ Programs

This repository holds the programs used for the NDSS 2017 paper MARX: Uncovering Class Hierarchies in C++ Programs.

Evaluation Data

The data used to evaluate Marx is available at zenodo.org.

Organization

Folder structure as follows:

• include contains the header files,
• src contains the source code itself,
• patch contains a patch to enable manual memory management for VEX,
• ida_export contains an IDA script creating a .dmp file,
• scripts contains helper scripts.

Development Setup

Requires CMake, at least version 2.8. As for IDEs, QtCreator works pretty well for C++ development and contains an useful debugger.

When using QtCreator, simply click on "Open Project" and select CMakeLists.txt. It makes sense to let the build directory point to a directory called build inside the project's root directory (in case your IDE does not honor CMake's RUNTIME_OUTPUT_DIRECTORY variable).

Debug builds are considerably slower but are necessary for proper debugging behavior. Make sure to set CMAKE_BUILD_TYPE accordingly in CMakeLists.txt (you can do so from within QtCreator). In desperate cases, try the option "Run CMake" from the context menu.

When developing from the command line, issue the following commands from the project's root directory:

mkdir build && cd build
cmake ..
make -j{CPU_COUNT}

The project requires a patched version of Valgrind. To be more exact, only the VEX sub-project is actually used and patched.

Download Valgrind from the official project page. We recommend checking out the subversion repository. Revision 3203 of VEX is known to work:

svn co svn://svn.valgrind.org/valgrind/trunk@15732 valgrind
cd valgrind/VEX/
svn update -r 3203

Configure the project as per its installation instructions. Switch to the VEX directory and apply the patch found in folder patch:

cd VEX
patch -p0 < ../marx/patch/heap_allocation_patch.diff

First configure Valgrind by issuing ./autogen.sh and ./configure. Then issue make and make install inside the VEX directory to install the VEX components. The CMake project tries to include the library /usr/local/lib/valgrind/libvex-amd64-linux.a. Make sure it exists.

Usage

When developing on a new binary, the first step is to export data from an IDA database. The IDAPython script found in ida_export creates a dump file {BINARY_NAME}.dmp and exports all necessary data used for the analysis in the folder the binary lies in. Remember to set the pure_virtual_addr in the IDAPython script before executing it. In case of Windows, the function is called _purecall. In Linux, it is called __cxa_pure_virtual.

After exporting all data, a config file for Marx has to be created manually. A config file looks like the following:

MODULENAME filezilla
TARGETDIR ../tests/filezilla/
FORMAT ELF64
NEWOPERATORS 2 431F80 432C00
EXTERNALMODULES 8 ../tests/libwx_gtk2u_aui/libwx_gtk2u_aui-3.1.so.0.0.0 ../tests/libwx_gtk2u_xrc/libwx_gtk2u_xrc-3.1.so.0.0.0 ../tests/libwx_gtk2u_adv/libwx_gtk2u_adv-3.1.so.0.0.0 ../tests/libwx_gtk2u_core/libwx_gtk2u_core-3.1.so.0.0.0 ../tests/libwx_baseu_net/libwx_baseu_net-3.1.so.0.0.0 ../tests/libwx_baseu/libwx_baseu-3.1.so.0.0.0 ../tests/libwx_gtk2u_html/libwx_gtk2u_html-3.1.so.0.0.0 ../tests/libwx_baseu_xml/libwx_baseu_xml-3.1.so.0.0.0

Further examples of config files can be seen in the evaluation data at zenodo.org.

When the config file is created, Marx can be executed by issuing the following command:

./marx ../tests/filezilla/config.cfg

Afterwards, the IDAPython script found in ida_import can be used to import the analyzed data back to IDA.

NOTE: Windows binaries have to be loaded at base address 0x0 (or rebased) in IDA before exporting them. Also, the IDAPython script only supports Windows binaries which are compiled with RTTI. Furthermore, specific functions have to be blacklisted in Windows binaries (because of compiler optimizations which would cause a lot of false-positives during the analysis) that are in multiple vtables but do not belong together. This is the case for example for short functions that do just zero a register and do nothing more. See for further details the helper script ida_win_find_blacklist_functions.py.