使用Angr进行二进制代码保护和加固的 实践分享

Angr是一个功能强大的二进制代码分析和漏洞挖掘工具。它可以用于保护和加固二进制代码，增强软件的安全性和鲁棒性。以下是使用Angr进行二进制代码保护和加固的 实践，并附带了一些使用示例。

1. 边界检查：Angr可以对二进制代码进行静态和动态的边界检查，以检测和防止缓冲区溢出漏洞。下面是一个示例，演示如何使用Angr对二进制代码进行静态边界检查：

import angr

project = angr.Project('binary')
cfg = project.analyses.CFG()

for addr in cfg.functions:
    function = cfg.functions[addr]
    for block in function.blocks:
        for insn in block.capstone.insns:
            if insn.mnemonic == 'call':
                target = insn.operands[0].value
                if not cfg.is_hooked(target):  # Check if the target is a library function
                    print(f"Potential call to function at address 0x{target:08x} in function at address 0x{addr:08x}")

2. 溢出检测和修复：Angr可以使用动态符号执行来模拟代码执行过程，以检测和修复缓冲区溢出漏洞。下面是一个示例，演示如何使用Angr检测和修复缓冲区溢出漏洞：

import angr
import claripy

project = angr.Project('binary')

@project.hook(0x401234, length=5)
def custom_read(state):
    buf = state.solver.BVS('buf', 16 * 8)  # Symbolic buffer with 16 bytes
    state.memory.store(state.regs.rdi, buf)  # Store the symbolic buffer in the target address
    state.regs.rax = claripy.BVV(16, 64)  # Return the size of the buffer
    state.ip = state.ip + 5  # Skip the original buffer read

state = project.factory.entry_state()
simgr = project.factory.simulation_manager(state)

simgr.explore(find=0x40123A)  # Find the target address of the vulnerability

if simgr.found:
    vuln_state = simgr.found[0]
    vuln_state.add_constraints(vuln_state.memory.load(vuln_state.regs.rdi + 16) == claripy.BVV(0x00, 8))  # Check if the buffer is null-terminated
    valid_solution = vuln_state.solver.satisfiable(extra_constraints=[vuln_state.regs.rdi != claripy.BVV(0, vuln_state.arch.bits)])  # Check if the buffer address is non-zero
    if valid_solution:
        print("Vulnerability detected and fixed!")
        fixed_buffer = vuln_state.solver.eval(vuln_state.memory.load(vuln_state.regs.rdi + 16, 16))
        print(f"Fixed buffer: {fixed_buffer}")

3. 代码混淆：Angr可以通过重写和重新排列指令来混淆二进制代码，增加代码的复杂性，使逆向分析变得困难。下面是一个示例，演示如何使用Angr对二进制代码进行代码混淆：

import angr
import random

def obfuscate_code(project):
    cfg = project.analyses.CFG()

    for addr in cfg.nodes:
        block = project.factory.block(addr)
        instructions = block.capstone.insns

        random.shuffle(instructions)  # Randomly shuffle the instructions

        new_block = claripy.BVV(b'', 0)
        for insn in instructions:
            insn_bytes = insn.bytes
            new_block = new_block.concat(insn_bytes)

        project.analyses.CFGEmulated(instructions=new_block, start_points=[addr])

project = angr.Project('binary')
obfuscate_code(project)

通过使用Angr的各种功能和特性，您可以更好地保护和加固二进制代码，增强软件的安全性和鲁棒性。这些 实践示例可以作为起点，帮助您开始使用Angr进行二进制代码保护和加固。