BARF - A multiplatform open source Binary Analysis and Reverse engineering Framework
The analysis of binary code is a crucial activity in many areas of the computer sciences and software engineering disciplines ranging from software security and program analysis to reverse engineering. Manual binary analysis is a difficult and time-consuming task and there are software tools that seek to automate or assist human analysts. However, most of these tools have several technical and commercial restrictions that limit access and use by a large portion of the academic and practitioner communities. BARF is an open source binary analysis framework that aims to support a wide range of binary code analysis tasks that are common in the information security discipline. It is a scriptable platform that supports instruction lifting from multiple architectures, binary translation to an intermediate representation, an extensible framework for code analysis plugins and interoperation with external tools such as debuggers, SMT solvers and instrumentation tools. The framework is designed primarily for human-assisted analysis but it can be fully automated.
The BARF project includes BARF and related tools and packages. So far the project is composed of the following items:
- BARF : A multiplatform open source Binary Analysis and Reverse engineering Framework
- PyAsmJIT : A JIT for the Intel x86_64 and ARM architecture.
- Tools built upon BARF :
- BARFgadgets : Lets you search , classifiy and verify ROP gadgets inside a binary program.
- BARFcfg : Lets you recover the control-flow graph of the functions of a binary program.
- BARFcg : Lets you recover the call graph of the functions of a binary program.
For more information, see:
- BARF: A multiplatform open source Binary Analysis and Reverse engineering Framework (Whitepaper) [ en ]
- BARFing Gadgets (ekoparty2014 presentation) [ es ]
Current status:
Latest Release | v0.3 |
---|---|
URL | https://github.com/programa-stic/barf-project/releases/tag/v0.3 |
Change Log | https://github.com/programa-stic/barf-project/blob/v0.3/CHANGELOG.md |
All packages were tested on Ubuntu 16.04 (x86_64).
BARF
BARF is a Python package for binary analysis and reverse engineering. It can:
- Load binary programs in different formats (
ELF
,PE
, etc), - It supports the Intel x86 architecture for 32 and 64 bits,
- It supports the ARM architecture for 32 bits,
- It operates on an intermediate language ( REIL ) thus all analysis algorithm are architecture-agnostic,
- It has integration with Z3 and CVC4 SMT solvers which means that you can express fragments of code as formulae and check restrictions on them.
Installation
BARF depends on the following SMT solvers:
- Z3 : A high-performance theorem prover being developed at Microsoft Research.
- CVC4 : An efficient open-source automatic theorem prover for satisfiability modulo theories (SMT) problems.
$ sudo python setup.py install
$ sudo python setup.py install --user
Notes
- Only one SMT solver is needed in order to work. You may choose between Z3 and CVC4 or install both. You can use the
barf-install-solver.sh
script which downloads and install both solver. - To run some tests you need to install PyAsmJIT first.
Quickstart
This is a very simple example which shows how to open a binary file and print each instruction with its translation to the intermediate language ( REIL ).
from barf import BARF
# Open binary file.
barf = BARF("examples/bin/x86/branch1")
# Print assembly instruction.
for addr, asm_instr, reil_instrs in barf.translate():
print("0x{addr:08x} {instr}".format(addr=addr, instr=asm_instr))
# Print REIL translation.
for reil_instr in reil_instrs:
print("{indent:11s} {instr}".format(indent="", instr=reil_instr))
.dot
file. # Recover CFG.
cfg = barf.recover_cfg()
# Save CFG to a .dot file.
cfg.save("branch1_cfg")
80483ed: 55 push ebp
80483ee: 89 e5 mov ebp,esp
80483f0: 83 ec 10 sub esp,0x10
80483f3: 8b 45 f8 mov eax,DWORD PTR [ebp-0x8]
80483f6: 8b 55 f4 mov edx,DWORD PTR [ebp-0xc]
80483f9: 01 d0 add eax,edx
80483fb: 83 c0 05 add eax,0x5
80483fe: 89 45 fc mov DWORD PTR [ebp-0x4],eax
8048401: 8b 45 fc mov eax,DWORD PTR [ebp-0x4]
8048404: c9 leave
8048405: c3 ret
ebp-0x4
, ebp-0x8
and ebp-0xc
in order to obtain a specific value in eax
register after executing the code. First, we add the instructions to the analyzer component.
from barf import BARF
# Open ELF file
barf = BARF("examples/bin/x86/constraint1")
# Add instructions to analyze.
for addr, asm_instr, reil_instrs in barf.translate(0x80483ed, 0x8048401):
for reil_instr in reil_instrs:
barf.code_analyzer.add_instruction(reil_instr)
# Get smt expression for eax and ebp registers
eap = barf.code_analyzer.get_register_expr("eax")
ebp = barf.code_analyzer.get_register_expr("ebp")
# Get smt expressions for memory locations (each one of 4 bytes)
a = barf.code_analyzer.get_memory_expr(ebp-0x8, 4)
b = barf.code_analyzer.get_memory_expr(ebp-0xc, 4)
c = barf.code_analyzer.get_memory_expr(ebp-0x4, 4)
# Set range for variables
barf.code_analyzer.set_preconditions([a >= 2, a <= 100])
barf.code_analyzer.set_preconditions([b >= 2, b <= 100])
# Set desired value for the result
barf.code_analyzer.set_postcondition(c == 13)
# Check satisfiability.
if barf.code_analyzer.check() == 'sat':
print("SAT!")
# Get concrete value for expressions.
eax_val = barf.code_analyzer.get_expr_value(eax)
a_val = barf.code_analyzer.get_expr_value(a)
b_val = barf.code_analyzer.get_expr_value(b)
c_val = barf.code_analyzer.get_expr_value(c)
# Print values.
print("eax : 0x{0:%08x} ({0})".format(eax_val))
print("ebp : 0x{0:%08x} ({0})".format(ebp_val))
print(" a : 0x{0:%08x} ({0})".format(a_val))
print(" b : 0x{0:%08x} ({0})".format(b_val))
print(" c : 0x{0:%08x} ({0})".format(c_val))
else:
print("UNSAT!")
Overview
The framework is divided in three main components: core , arch and analysis .
Core
This component contains essential modules:
-
REIL
: Provides definitions for the REIL language. It, also, implements an emulator and a parser . -
SMT
: Provides means to interface with Z3 SMT solver. Also, it provides functionality to translate REIL instructions to SMT expressions. -
BI
: The Binary Interface module is responsible for loading binary files for processing (it uses [PEFile] and [PyELFTools].)
Arch
Each supported architecture is provided as a subcomponent which contains the following modules.
-
Architecture
: Describes the architecture, i.e., registers, memory address size. -
Translator
: Provides translators to REIL for each supported instruction. -
Disassembler
: Provides disassembling functionalities (it uses Capstone.) -
Parser
: Transforms instruction in string to object form (provided by the Instruction module.)
Analysis
So far this component consists of two modules: Control-Flow Graph , Call Graph and Code Analyzer . The first two, provides functionality for CFG and CG recovery, respectively. The latter, its a high-level interface to the SMT-solver-related functionalities.
Directory Structure
barf/ Framework's main directory.
doc/ Documentation.
examples/ Basic example scripts that show various functionalities.
scripts/ Installation scripts.
tests/ BARF package tests.
tools/ Tools build upon BARF.
Notes
SMT solver interfacing is provided by the file
core/smt/smtlibv2.py
taken from PySymEmu . Tools
BARFgadgets
BARFgadgets
is a Python script built upon BARF that lets you search , classifiy and verify ROP gadgets inside a binary program. The search stage finds all ret
-, jmp
- and call
-ended gadgets inside the binary. The classification stage classifies previously found gadgets according to the following types: - No-Operation,
- Move Register,
- Load Constant,
- Arithmetic/Logical Operation,
- Load Memory,
- Store Memory,
- Arithmetic/Logical Load,
- Arithmetic/Logical Store and
- Undefined.
usage: BARFgadgets [-h] [--version] [--bdepth BDEPTH] [--idepth IDEPTH] [-u]
[-c] [-v] [-o OUTPUT] [-t] [--sort {addr,depth}] [--color]
[--show-binary] [--show-classification]
filename
Tool for finding, classifying and verifying ROP gadgets.
positional arguments:
filename Binary file name.
optional arguments:
-h, --help show this help message and exit
--version Display version.
--bdepth BDEPTH Gadget depth in number of bytes.
--idepth IDEPTH Gadget depth in number of instructions.
-u, --unique Remove duplicate gadgets (in all steps).
-c, --classify Run gadgets classification.
-v, --verify Run gadgets verification (includes classification).
-o OUTPUT, --output OUTPUT
Save output to file.
-t, --time Print time of each processing step.
--sort {addr,depth} Sort gadgets by address or depth (number of
instructions) in ascending order.
--color Format gadgets with ANSI color sequences, for output
in a 256-color terminal or console.
--show-binary Show binary code for each gadget.
--show-classification
Show classification for each gadget.
For more information, see README . BARFcfg
BARFcfg
is a Python script built upon BARF that lets you recover the control-flow graph of a binary program. usage: BARFcfg [-h] [-s SYMBOL_FILE] [-a] [-o RECOVER_ONE] [-f {graph,text}]
[-t] [-d OUTPUT_DIR] [-b] [-r]
filename
Tool for recovering CFG of a binary.
positional arguments:
filename Binary file name.
optional arguments:
-h, --help show this help message and exit
-s SYMBOL_FILE, --symbol-file SYMBOL_FILE
Load symbols from file.
-a, --recover-all Recover all functions.
-o RECOVER_ONE, --recover-one RECOVER_ONE
Recover specified function.
-f {graph,text}, --format {graph,text}
Output format.
-t, --time Print process time.
-d OUTPUT_DIR, --output-dir OUTPUT_DIR
Ouput directory.
-b, --brief Brief output.
-r, --show-reil Show REIL translation.
For more information, see README . BARFcg
BARFcg
is a Python script built upon BARF that lets you recover the call graph of a binary program. usage: BARFcg [-h] [-s SYMBOL_FILE] [-a] [-t] filename
Tool for recovering CG of a binary.
positional arguments:
filename Binary file name.
optional arguments:
-h, --help show this help message and exit
-s SYMBOL_FILE, --symbol-file SYMBOL_FILE
Load symbols from file.
-a, --recover-all Recover all functions.
-t, --time Print process time.
For more information, see README . PyAsmJIT
PyAsmJIT is a Python package for x86_64/ARM assembly code generation and execution.
This package was developed in order to test BARF instruction translation from x86_64/ARM to REIL. The main idea is to be able to run fragments of code natively. Then, the same fragment is translated to REIL and executed in a REIL VM. Finally, both final contexts (the one obtained through native execution and the one from emulation) are compare for differences.
For more information, see PyAsmJit .
BARF - A multiplatform open source Binary Analysis and Reverse engineering Framework
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