"Symbolic Exploit Assistant" ( SEA ) is a small tool designed to assist the discovery and construction of exploits in binary programs. SEA is free software (GPL3) and includes a minimal toolkit (BSD) to quickly develop binary analysis tools in Python. This project is developed in collaboration between the research institutes CIFASIS (Rosario, Argentina) and VERIMAG (Grenoble, France) in an effort to improve security in binary programs.
We can use SEA to deduce exploitability conditions of binary programs without executing code. For example, if we have the following assembly code (expressed in a simple intermediate language):
1: call 2: t0 := eax xor 42 3: eax := t0 4: ebx := eax + t0 5: if not (t0 == 0) then jump ebx
SEA allows us to enforce this particular sequence of instructions in order to jump to address 0xdeadc0de. The tool will track and propagate backwards all the constraints required. In this case, SEA detects the EAX register as the only free operand and returns its initial condition:
eax := 0x6f56e06f
SEA also performs pointer detection (stack, heap and globals) in traces. These pointers can be used to enforce particular memory conditions, even if they require to overflow buffers. The current implementation can be used to "solve", some of the examples of Gera's Insecure Programming:
- Compiled with gcc 4.8.0 (default parameters). The complete analysis is here. The tool found it solvable if the user inputs data using standard input.
- Compiled with Visual Studio 2005 (default parameters), The complete analysis is here. The tool founds it is solvable if the user controls the initial value of a local variable (which is usually not possible)
- Compiled with gcc 4.8.0 (default parameters), The tool founds it is solvable if the user inputs data using command line arguments (allowing to execute a call to system).
Documentation, examples and the complete list of features can be found in the wiki. The issue tracker is available. Discussion for support or collaboration is available in #sea-tool @ irc.freenode.net
To get started, you should have Python 2.7. To prepare the tool, the official Z3 Python binding (z3py) should be installed. Fortunately, just executing boostrap.sh will download and compile z3py. After it finishes compiling, SEA is ready to be used.
NOTE: Right now, SEA uses REIL code as input, to analyze a path. Unfortunately, REIL can be only generated from an executable file using BinNavi which runs in the top of IDA-Pro (two proprietary and expensive programs) Hopefully, this will change soon when SEA supports open frameworks for binary analysis like Bincoa or BAP.