Created
April 4, 2022 01:32
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spaceheros 2022 launch code solve
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import angr, claripy | |
from pwn import * | |
file_name = "./launch_code" | |
# 1639874435 | |
# Test nonce | |
nonce = 1639874435 | |
def get_codes(nonce): | |
if isinstance(nonce,bytes): | |
nonce = int(nonce) | |
num1 = claripy.BVS('num1', 8*8) | |
num2 = claripy.BVS('num2', 8*8) | |
num3 = claripy.BVS('num3', 8*8) | |
num4 = claripy.BVS('num4', 8*8) | |
class hookNothing(angr.SimProcedure): | |
IS_FUNCTION = True | |
def run(self): | |
return 0 # Fair dice roll | |
# Place real nonce here | |
class hookNonce(angr.SimProcedure): | |
IS_FUNCTION = True | |
def run(self): | |
return nonce | |
class hookGetNums(angr.SimProcedure): | |
IS_FUNCTION = True | |
def run(self): | |
self.state.regs.r12 = num1 | |
self.state.regs.r11 = num2 | |
self.state.regs.r10 = num3 | |
self.state.regs.r9 = num4 | |
return num4 | |
p = angr.Project('./launch_code', auto_load_libs=False) | |
# Speed up our solve | |
for sym in ["print_logo", "timeout", "srand", "time"]: | |
p.hook_symbol(sym, hookNothing()) | |
# Use predictable nonce | |
p.hook_symbol("rand", hookNonce()) | |
# p.hook_symbol("get_launch_auth", hookGetNums()) | |
state = p.factory.entry_state() | |
simgr = p.factory.simgr(state) | |
simgr.explore(find=0x004016cd) | |
path = simgr.found[0] | |
solver = path.solver | |
vals = "{} {} {} {}".format(solver.eval(num1), | |
solver.eval(num2), | |
solver.eval(num3), | |
solver.eval(num4)) | |
print(path.posix.dumps(0)) | |
return vals | |
# p = process(file_name) | |
#0.cloud.chals.io:12499 | |
p = remote("0.cloud.chals.io",12499) | |
p.readuntil(b'Random nonce = ') | |
nonce = p.readline().replace(b'\n',b'') | |
print(nonce) | |
codes = get_codes(nonce) | |
print(codes) | |
p.interactive() | |
# shctf{Every-cUb1c-1nch-0f-spAce-is-a-m1racl3} |
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