Angr - Examples

PreviousAngr NextZ3 - Satisfiability Modulo Theories (SMT)

Last updated 7 days ago

import angr import sys def main(argv): path_to_binary = argv[1] # :string project = angr.Project(path_to_binary) # Start in main() initial_state = project.factory.entry_state() # Start simulation simulation = project.factory.simgr(initial_state) # Find the way yo reach the good address good_address = 0x804867d # Avoiding this address avoid_address = 0x080485A8 simulation.explore(find=good_address, avoid=avoid_address) # If found a way to reach the address if simulation.found: solution_state = simulation.found[0] # Print the string that Angr wrote to stdin to follow solution_state print(solution_state.posix.dumps(sys.stdin.fileno())) else: raise Exception('Could not find the solution') if __name__ == '__main__': main(sys.argv)

# If you don't know the address you want to recah, but you know it's printing something # You can also indicate that info import angr import sys def main(argv): path_to_binary = argv[1] project = angr.Project(path_to_binary) initial_state = project.factory.entry_state() simulation = project.factory.simgr(initial_state) def is_successful(state): #Successful print stdout_output = state.posix.dumps(sys.stdout.fileno()) return b'Good Job.' in stdout_output def should_abort(state): #Avoid this print stdout_output = state.posix.dumps(sys.stdout.fileno()) return b'Try again.' in stdout_output simulation.explore(find=is_successful, avoid=should_abort) if simulation.found: solution_state = simulation.found[0] print(solution_state.posix.dumps(sys.stdin.fileno())) else: raise Exception('Could not find the solution') if __name__ == '__main__': main(sys.argv)

# Angr doesn't currently support reading multiple things with scanf (Ex: # scanf("%u %u).) You will have to tell the simulation engine to begin the # program after scanf is called and manually inject the symbols into registers. import angr import claripy import sys def main(argv): path_to_binary = argv[1] project = angr.Project(path_to_binary) # Address were you want to indicate the relation BitVector - registries start_address = 0x80488d1 initial_state = project.factory.blank_state(addr=start_address) # Create Bit Vectors password0_size_in_bits = 32 # :integer password0 = claripy.BVS('password0', password0_size_in_bits) password1_size_in_bits = 32 # :integer password1 = claripy.BVS('password1', password1_size_in_bits) password2_size_in_bits = 32 # :integer password2 = claripy.BVS('password2', password2_size_in_bits) # Relate it Vectors with the registriy values you are interested in to reach an address initial_state.regs.eax = password0 initial_state.regs.ebx = password1 initial_state.regs.edx = password2 simulation = project.factory.simgr(initial_state) def is_successful(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Good Job.'.encode() in stdout_output def should_abort(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Try again.'.encode() in stdout_output simulation.explore(find=is_successful, avoid=should_abort) if simulation.found: solution_state = simulation.found[0] solution0 = solution_state.solver.eval(password0) solution1 = solution_state.solver.eval(password1) solution2 = solution_state.solver.eval(password2) # Aggregate and format the solutions you computed above, and then print # the full string. Pay attention to the order of the integers, and the # expected base (decimal, octal, hexadecimal, etc). solution = ' '.join(map('{:x}'.format, [ solution0, solution1, solution2 ])) # :string print(solution) else: raise Exception('Could not find the solution') if __name__ == '__main__': main(sys.argv)

# Put bit vectors in th stack to find out the vallue that stack position need to # have to reach a rogram flow import angr import claripy import sys def main(argv): path_to_binary = argv[1] project = angr.Project(path_to_binary) # Go to some address after the scanf where values have already being set in the stack start_address = 0x8048697 initial_state = project.factory.blank_state(addr=start_address) # Since we are starting after scanf, we are skipping this stack construction # step. To make up for this, we need to construct the stack ourselves. Let us # start by initializing ebp in the exact same way the program does. initial_state.regs.ebp = initial_state.regs.esp # In this case scanf("%u %u") is used, so 2 BVS are going to be needed password0 = claripy.BVS('password0', 32) password1 = claripy.BVS('password1', 32) # Now, in the address were you have stopped, check were are the scanf values saved # Then, substrack form the esp registry the needing padding to get to the # part of the stack were the scanf values are being saved and push the BVS # (see the image below to understan this -8) padding_length_in_bytes = 8 # :integer initial_state.regs.esp -= padding_length_in_bytes initial_state.stack_push(password0) initial_state.stack_push(password1) simulation = project.factory.simgr(initial_state) def is_successful(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Good Job.'.encode() in stdout_output def should_abort(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Try again.'.encode() in stdout_output simulation.explore(find=is_successful, avoid=should_abort) if simulation.found: solution_state = simulation.found[0] solution0 = solution_state.solver.eval(password0) solution1 = solution_state.solver.eval(password1) solution = ' '.join(map(str, [ solution0, solution1 ])) print(solution) else: raise Exception('Could not find the solution') if __name__ == '__main__': main(sys.argv)

import angr import claripy import sys def main(argv): path_to_binary = argv[1] project = angr.Project(path_to_binary) #Get an address after the scanf. Once the input has already being saved in the memory positions start_address = 0x8048606 initial_state = project.factory.blank_state(addr=start_address) # The binary is calling scanf("%8s %8s %8s %8s"). # So we need 4 BVS of size 8*8 password0 = claripy.BVS('password0', 8*8) password1 = claripy.BVS('password1', 8*8) password2 = claripy.BVS('password2', 8*8) password3 = claripy.BVS('password3', 8*8) # Write the symbolic BVS in the memory positions password0_address = 0xa29faa0 initial_state.memory.store(password0_address, password0) password1_address = 0xa29faa8 initial_state.memory.store(password1_address, password1) password2_address = 0xa29fab0 initial_state.memory.store(password2_address, password2) password3_address = 0xa29fab8 initial_state.memory.store(password3_address, password3) simulation = project.factory.simgr(initial_state) def is_successful(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Good Job.'.encode() in stdout_output def should_abort(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Try again.'.encode() in stdout_output simulation.explore(find=is_successful, avoid=should_abort) if simulation.found: solution_state = simulation.found[0] # Get the values the memory addresses should store solution0 = solution_state.solver.eval(password0,cast_to=bytes).decode() solution1 = solution_state.solver.eval(password1,cast_to=bytes).decode() solution2 = solution_state.solver.eval(password2,cast_to=bytes).decode() solution3 = solution_state.solver.eval(password3,cast_to=bytes).decode() solution = ' '.join([ solution0, solution1, solution2, solution3 ]) print(solution) else: raise Exception('Could not find the solution') if __name__ == '__main__': main(sys.argv)

import angr import claripy import sys def main(argv): path_to_binary = argv[1] project = angr.Project(path_to_binary) # Get address after scanf start_address = 0x804869e initial_state = project.factory.blank_state(addr=start_address) # The binary is calling scanf("%8s %8s") so 2 BVS are needed. password0 = claripy.BVS('password0', 8*8) password1 = claripy.BVS('password0', 8*8) # Find a coupble of addresses that aren't used by the binary (like 0x4444444 & 0x4444454) # The address generated by mallosc is going to be saved in some address # Then, make that address point to the fake heap addresses were the BVS are going to be saved fake_heap_address0 = 0x4444444 pointer_to_malloc_memory_address0 = 0xa79a118 initial_state.memory.store(pointer_to_malloc_memory_address0, fake_heap_address0, endness=project.arch.memory_endness) fake_heap_address1 = 0x4444454 pointer_to_malloc_memory_address1 = 0xa79a120 initial_state.memory.store(pointer_to_malloc_memory_address1, fake_heap_address1, endness=project.arch.memory_endness) # Save the VBS in the new fake heap addresses created initial_state.memory.store(fake_heap_address0, password0) initial_state.memory.store(fake_heap_address1, password1) simulation = project.factory.simgr(initial_state) def is_successful(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Good Job.'.encode() in stdout_output def should_abort(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Try again.'.encode() in stdout_output simulation.explore(find=is_successful, avoid=should_abort) if simulation.found: solution_state = simulation.found[0] solution0 = solution_state.solver.eval(password0,cast_to=bytes).decode() solution1 = solution_state.solver.eval(password1,cast_to=bytes).decode() solution = ' '.join([ solution0, solution1 ]) print(solution) else: raise Exception('Could not find the solution') if __name__ == '__main__': main(sys.argv)

#In this challenge a password is read from a file and we want to simulate its content import angr import claripy import sys def main(argv): path_to_binary = argv[1] project = angr.Project(path_to_binary) # Get an address just before opening the file with th simbolic content # Or at least when the file is not going to suffer more changes before being read start_address = 0x80488db initial_state = project.factory.blank_state(addr=start_address) # Specify the filena that is going to open # Note that in theory, the filename could be symbolic. filename = 'WCEXPXBW.txt' symbolic_file_size_bytes = 64 # Create a BV which is going to be the content of the simbolic file password = claripy.BVS('password', symbolic_file_size_bytes * 8) # Create the file simulation with the simbolic content password_file = angr.storage.SimFile(filename, content=password) # Add the symbolic file we created to the symbolic filesystem. initial_state.fs.insert(filename, password_file) simulation = project.factory.simgr(initial_state) def is_successful(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Good Job.'.encode() in stdout_output def should_abort(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Try again.'.encode() in stdout_output simulation.explore(find=is_successful, avoid=should_abort) if simulation.found: solution_state = simulation.found[0] solution = solution_state.solver.eval(password,cast_to=bytes).decode() print(solution) else: raise Exception('Could not find the solution') if __name__ == '__main__': main(sys.argv)

# Hello world, my name is John. # ^ ^ # ^ address 0 ^ address 24 (count the number of characters) # In order to represent this in memory, we would want to write the string to # the beginning of the file: # # hello_txt_contents = claripy.BVV('Hello world, my name is John.', 30*8) # # Perhaps, then, we would want to replace John with a # symbolic variable. We would call: # # name_bitvector = claripy.BVS('symbolic_name', 4*8) # # Then, after the program calls fopen('hello.txt', 'r') and then # fread(buffer, sizeof(char), 30, hello_txt_file), the buffer would contain # the string from the file, except four symbolic bytes where the name would be # stored. # (!)

# After perform some complex poperations to the input the program checks # char by char the password against another password saved, like in the snippet: # # #define REFERENCE_PASSWORD = "AABBCCDDEEFFGGHH"; # int check_equals_AABBCCDDEEFFGGHH(char* to_check, size_t length) { # uint32_t num_correct = 0; # for (int i=0; i<length; ++i) { # if (to_check[i] == REFERENCE_PASSWORD[i]) { # num_correct += 1; # } # } # return num_correct == length; # } # # ... # # char* input = user_input(); # char* encrypted_input = complex_function(input); # if (check_equals_AABBCCDDEEFFGGHH(encrypted_input, 16)) { # puts("Good Job."); # } else { # puts("Try again."); # } # # The function checks if *to_check == "AABBCCDDEEFFGGHH". This is very RAM consumming # as the computer needs to branch every time the if statement in the loop was called (16 # times), resulting in 2^16 = 65,536 branches, which will take too long of a # time to evaluate for our needs. import angr import claripy import sys def main(argv): path_to_binary = argv[1] project = angr.Project(path_to_binary) initial_state = project.factory.entry_state() simulation = project.factory.simgr(initial_state) # Get an address to check after the complex function and before the "easy compare" operation address_to_check_constraint = 0x8048671 simulation.explore(find=address_to_check_constraint) if simulation.found: solution_state = simulation.found[0] # Find were the input that is going to be compared is saved in memory constrained_parameter_address = 0x804a050 constrained_parameter_size_bytes = 16 # Set the bitvector constrained_parameter_bitvector = solution_state.memory.load( constrained_parameter_address, constrained_parameter_size_bytes ) # Indicate angr that this BV at this point needs to be equal to the password constrained_parameter_desired_value = 'BWYRUBQCMVSBRGFU'.encode() solution_state.add_constraints(constrained_parameter_bitvector == constrained_parameter_desired_value) print(solution_state.posix.dumps(sys.stdin.fileno())) else: raise Exception('Could not find the solution') if __name__ == '__main__': main(sys.argv)

import angr import claripy import sys def main(argv): path_to_binary = argv[1] project = angr.Project(path_to_binary) initial_state = project.factory.entry_state() simulation = project.factory.simgr(initial_state) # Set simulation technique simulation.use_technique(angr.exploration_techniques.Veritesting()) def is_successful(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Good Job.'.encode() in stdout_output # :boolean def should_abort(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Try again.'.encode() in stdout_output # :boolean simulation.explore(find=is_successful, avoid=should_abort) if simulation.found: solution_state = simulation.found[0] print(solution_state.posix.dumps(sys.stdin.fileno())) else: raise Exception('Could not find the solution') if __name__ == '__main__': main(sys.argv)

# This level performs the following computations: # # 1. Get 16 bytes of user input and encrypt it. # 2. Save the result of check_equals_AABBCCDDEEFFGGHH (or similar) # 3. Get another 16 bytes from the user and encrypt it. # 4. Check that it's equal to a predefined password. # # The ONLY part of this program that we have to worry about is #2. We will be # replacing the call to check_equals_ with our own version, using a hook, since # check_equals_ will run too slowly otherwise. import angr import claripy import sys def main(argv): path_to_binary = argv[1] project = angr.Project(path_to_binary) initial_state = project.factory.entry_state() # Hook the address of the call to hook indicating th length of the instruction (of the call) check_equals_called_address = 0x80486b8 instruction_to_skip_length = 5 @project.hook(check_equals_called_address, length=instruction_to_skip_length) def skip_check_equals_(state): #Load the input of the function reading direcly the memory user_input_buffer_address = 0x804a054 user_input_buffer_length = 16 user_input_string = state.memory.load( user_input_buffer_address, user_input_buffer_length ) # Create a simbolic IF that if the loaded string frommemory is the expected # return True (1) if not returns False (0) in eax check_against_string = 'XKSPZSJKJYQCQXZV'.encode() # :string state.regs.eax = claripy.If( user_input_string == check_against_string, claripy.BVV(1, 32), claripy.BVV(0, 32) ) simulation = project.factory.simgr(initial_state) def is_successful(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Good Job.'.encode() in stdout_output def should_abort(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Try again.'.encode() in stdout_output simulation.explore(find=is_successful, avoid=should_abort) if simulation.found: solution_state = simulation.found[0] solution = solution_state.posix.dumps(sys.stdin.fileno()).decode() print(solution) else: raise Exception('Could not find the solution') if __name__ == '__main__': main(sys.argv)

# Hook to the function called check_equals_WQNDNKKWAWOLXBAC import angr import claripy import sys def main(argv): path_to_binary = argv[1] project = angr.Project(path_to_binary) initial_state = project.factory.entry_state() # Define a class and a tun method to hook completelly a function class ReplacementCheckEquals(angr.SimProcedure): # This C code: # # int add_if_positive(int a, int b) { # if (a >= 0 && b >= 0) return a + b; # else return 0; # } # # could be simulated with python: # # class ReplacementAddIfPositive(angr.SimProcedure): # def run(self, a, b): # if a >= 0 and b >=0: # return a + b # else: # return 0 # # run(...) receives the params of the hooked function def run(self, to_check, length): user_input_buffer_address = to_check user_input_buffer_length = length # Read the data from the memory address given to the function user_input_string = self.state.memory.load( user_input_buffer_address, user_input_buffer_length ) check_against_string = 'WQNDNKKWAWOLXBAC'.encode() # Return 1 if equals to the string, 0 otherways return claripy.If( user_input_string == check_against_string, claripy.BVV(1, 32), claripy.BVV(0, 32) ) # Hook the check_equals symbol. Angr automatically looks up the address # associated with the symbol. Alternatively, you can use 'hook' instead # of 'hook_symbol' and specify the address of the function. To find the # correct symbol, disassemble the binary. # (!) check_equals_symbol = 'check_equals_WQNDNKKWAWOLXBAC' # :string project.hook_symbol(check_equals_symbol, ReplacementCheckEquals()) simulation = project.factory.simgr(initial_state) def is_successful(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Good Job.'.encode() in stdout_output def should_abort(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Try again.'.encode() in stdout_output simulation.explore(find=is_successful, avoid=should_abort) if simulation.found: solution_state = simulation.found[0] solution = solution_state.posix.dumps(sys.stdin.fileno()).decode() print(solution) else: raise Exception('Could not find the solution') if __name__ == '__main__': main(sys.argv)

# This time, the solution involves simply replacing scanf with our own version, # since Angr does not support requesting multiple parameters with scanf. import angr import claripy import sys def main(argv): path_to_binary = argv[1] project = angr.Project(path_to_binary) initial_state = project.factory.entry_state() class ReplacementScanf(angr.SimProcedure): # The code uses: 'scanf("%u %u", ...)' def run(self, format_string, param0, param1): scanf0 = claripy.BVS('scanf0', 32) scanf1 = claripy.BVS('scanf1', 32) # Get the addresses from the params and store the BVS in memory scanf0_address = param0 self.state.memory.store(scanf0_address, scanf0, endness=project.arch.memory_endness) scanf1_address = param1 self.state.memory.store(scanf1_address, scanf1, endness=project.arch.memory_endness) # Now, we want to 'set aside' references to our symbolic values in the # globals plugin included by default with a state. You will need to # store multiple bitvectors. You can either use a list, tuple, or multiple # keys to reference the different bitvectors. self.state.globals['solutions'] = (scanf0, scanf1) scanf_symbol = '__isoc99_scanf' project.hook_symbol(scanf_symbol, ReplacementScanf()) simulation = project.factory.simgr(initial_state) def is_successful(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Good Job.'.encode() in stdout_output def should_abort(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Try again.'.encode() in stdout_output simulation.explore(find=is_successful, avoid=should_abort) if simulation.found: solution_state = simulation.found[0] # Grab whatever you set aside in the globals dict. stored_solutions = solution_state.globals['solutions'] solution = ' '.join(map(str, map(solution_state.solver.eval, stored_solutions))) print(solution) else: raise Exception('Could not find the solution') if __name__ == '__main__': main(sys.argv)

# This challenge is the exact same as the first challenge, except that it was # compiled as a static binary. Normally, Angr automatically replaces standard # library functions with SimProcedures that work much more quickly. # # To solve the challenge, manually hook any standard library c functions that # are used. Then, ensure that you begin the execution at the beginning of the # main function. Do not use entry_state. # # Here are a few SimProcedures Angr has already written for you. They implement # standard library functions. You will not need all of them: # angr.SIM_PROCEDURES['libc']['malloc'] # angr.SIM_PROCEDURES['libc']['fopen'] # angr.SIM_PROCEDURES['libc']['fclose'] # angr.SIM_PROCEDURES['libc']['fwrite'] # angr.SIM_PROCEDURES['libc']['getchar'] # angr.SIM_PROCEDURES['libc']['strncmp'] # angr.SIM_PROCEDURES['libc']['strcmp'] # angr.SIM_PROCEDURES['libc']['scanf'] # angr.SIM_PROCEDURES['libc']['printf'] # angr.SIM_PROCEDURES['libc']['puts'] # angr.SIM_PROCEDURES['libc']['exit'] # # As a reminder, you can hook functions with something similar to: # project.hook(malloc_address, angr.SIM_PROCEDURES['libc']['malloc']()) # # There are many more, see: # https://github.com/angr/angr/tree/master/angr/procedures/libc import angr import sys def main(argv): path_to_binary = argv[1] project = angr.Project(path_to_binary) initial_state = project.factory.entry_state() #Find the addresses were the lib functions are loaded in the binary #For example you could find: call 0x804ed80 <__isoc99_scanf> project.hook(0x804ed40, angr.SIM_PROCEDURES['libc']['printf']()) project.hook(0x804ed80, angr.SIM_PROCEDURES['libc']['scanf']()) project.hook(0x804f350, angr.SIM_PROCEDURES['libc']['puts']()) project.hook(0x8048d10, angr.SIM_PROCEDURES['glibc']['__libc_start_main']()) simulation = project.factory.simgr(initial_state) def is_successful(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Good Job.'.encode() in stdout_output # :boolean def should_abort(state): stdout_output = state.posix.dumps(sys.stdout.fileno()) return 'Try again.'.encode() in stdout_output # :boolean simulation.explore(find=is_successful, avoid=should_abort) if simulation.found: solution_state = simulation.found[0] print(solution_state.posix.dumps(sys.stdin.fileno()).decode()) else: raise Exception('Could not find the solution') if __name__ == '__main__': main(sys.argv)

Angr - Examples

Input per raggiungere l'indirizzo (indicando l'indirizzo)

Input per raggiungere l'indirizzo (indicando le stampe)

Valori del registro

Valori dello stack

Valori di memoria statica (Variabili globali)

Valori di Memoria Dinamica (Malloc)

Simulazione di File

Applicare Vincoli

Simulation Managers

Hooking/Bypassing una chiamata a una funzione

Hooking a function / Simprocedure

Simula scanf con diversi parametri

Binaries Statici