-
Notifications
You must be signed in to change notification settings - Fork 11
/
unico.py
338 lines (285 loc) · 13.2 KB
/
unico.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
from __future__ import print_function
from unicorn import *
from unicorn.x86_const import *
import pefile
import os
import re
import sys
import struct
import socket
class Unico:
STACK_LIMIT = 0x117d000
STACK_BASE = 0x1180000
HOOK_BASE = 0x2000000
EXIT_ADDRESS = 0xfffff000
IAT_ENTRIES = {}
EIP_HOOKS = {}
IAT_HOOKS = {}
LAST_IAT_NAME = None
def __init__(self):
Unico.IAT_ENTRIES = {}
Unico.EIP_HOOKS = {}
Unico.IAT_HOOKS = {}
Unico.LAST_IAT_NAME = None
self.pe = None
self.init_hooks = []
self.add_default_hooks()
self.add_socket_hooks()
def add_default_hooks(self):
def hook_GetModuleHandleW(uc, args):
Unico.retn(uc, 4)
return self.pe.OPTIONAL_HEADER.ImageBase
def hook_strcpy(uc, args):
addr_dst = int(args[0])
addr_src = int(args[1])
data = Unico.mem_read_cstr(uc, addr_src, include_null=True)
uc.mem_write(addr_dst, data)
Unico.log(uc, "IAT hook: strcpy 0x%x -> 0x%x %r" % (addr_src, addr_dst, data))
return addr_dst
def hook_memcpy(uc, args):
addr_dst = int(args[0])
addr_src = int(args[1])
size = int(args[2])
data = uc.mem_read(addr_src, size)
uc.mem_write(addr_dst, data)
Unico.log(uc, "IAT hook: memcpy 0x%x -> 0x%x %r" % (addr_src, addr_dst, data))
return addr_dst
def hook_memset(uc, args):
addr_ptr = int(args[0])
value = int(args[1])
size = int(args[2])
data = chr(value) * size
uc.mem_write(addr_ptr, data)
Unico.log(uc, "IAT hook: memset 0x%x 0x%x 0x%x" % (addr_ptr, value, size))
return addr_ptr
self.add_iat_hook('_initterm_e', lambda uc, args: 0)
self.add_iat_hook('IsDebuggerPresent', lambda uc, args: 0)
self.add_iat_hook('ExitProcess', Unico.stop)
self.add_iat_hook('GetModuleHandleW', hook_GetModuleHandleW)
self.add_iat_hook('strcpy', hook_strcpy)
self.add_iat_hook('memcpy', hook_memcpy)
self.add_iat_hook('memset', hook_memset)
def add_socket_hooks(self):
def hook_inet_addr(uc, args):
addr_cp = int(args[0])
cp = Unico.mem_read_cstr(uc, addr_cp)
Unico.log(uc, "IAT hook: inet_addr %r" % cp)
addr = 0
for x in reversed(cp.split('.')):
addr = (addr << 8) + int(x)
return addr
def hook_getaddrinfo(uc, args):
addr_name = int(args[0])
addr_service = int(args[1])
name = Unico.mem_read_cstr(uc, addr_name)
service = Unico.mem_read_cstr(uc, addr_service)
Unico.log(uc, "IAT hook: getaddrinfo '%s:%s'" % (name, service))
return 0
def hook_gethostbyname(uc, args):
addr_name = int(args[0])
hostname = Unico.mem_read_cstr(uc, addr_name)
Unico.log(uc, "IAT hook: gethostbyname '%s'" % hostname)
def hook_htons(uc, args):
arg = int(args[0])
Unico.log(uc, "IAT hook: htons %d" % arg)
return socket.htons(arg)
def hook_bind(uc, args):
addr_sockaddr = int(args[1])
family, port, addr = struct.unpack('>HH4s', uc.mem_read(addr_sockaddr, 8))
ipaddr = socket.inet_ntoa(addr)
Unico.log(uc, "IAT hook: socket bind '%s:%d'" % (ipaddr, port))
return 0
def hook_connect(uc, args):
addr_sockaddr = int(args[1])
family, port, addr = struct.unpack('>HH4s', uc.mem_read(addr_sockaddr, 8))
ipaddr = socket.inet_ntoa(addr)
Unico.log(uc, "IAT hook: socket connect '%s:%d'" % (ipaddr, port))
return 0
def hook_WSASend(uc, args):
addr_buf = int(args[1])
length, addr_buf = struct.unpack('<II', uc.mem_read(addr_buf, 8))
data = uc.mem_read(addr_buf, length)
Unico.log(uc, "IAT hook: socket send %r" % str(data))
return 0
def hook_send(uc, args):
addr_buf = int(args[1])
length = int(args[2])
data = uc.mem_read(addr_buf, length)
Unico.log(uc, "IAT hook: socket send %r" % str(data))
return length
self.add_iat_hook('inet_addr', hook_inet_addr)
self.add_iat_hook('getaddrinfo', hook_getaddrinfo)
self.add_iat_hook('gethostbyname', hook_gethostbyname)
self.add_iat_hook('htons', hook_htons)
self.add_iat_hook('WSAbind', hook_bind)
self.add_iat_hook('bind', hook_bind)
self.add_iat_hook('WSAConnect', hook_connect)
self.add_iat_hook('connect', hook_connect)
self.add_iat_hook('WSASend', hook_WSASend)
self.add_iat_hook('send', hook_send)
def add_init_hook(self, handler):
self.init_hooks.append(handler)
def add_iat_hook(self, name, handler):
"""handler(uc, args)"""
Unico.IAT_HOOKS[name] = handler
def add_eip_hook(self, address, handler):
"""handler(uc, address, size)"""
Unico.EIP_HOOKS[address] = handler
@staticmethod
def retn(uc, n):
esp = uc.reg_read(UC_X86_REG_ESP)
retaddr_mem = str(uc.mem_read(esp, 4))
retaddr = struct.unpack('<I', retaddr_mem)[0]
uc.mem_write(esp+n, retaddr_mem)
uc.reg_write(UC_X86_REG_ESP, esp+n)
@staticmethod
def stop(uc, *args):
uc.reg_write(UC_X86_REG_EIP, Unico.EXIT_ADDRESS)
@staticmethod
def skip(uc, address, size):
return address + size
@staticmethod
def mem_read_cstr(uc, addr, include_null=False):
data = uc.mem_read(addr, 8192)
m = re.search(r'^[^\x00]*', str(data))
cstr = m.group(0)
if include_null:
cstr += '\x00'
return cstr
@staticmethod
def log(uc, message):
print("[0x%x] %s" % (uc.reg_read(UC_X86_REG_EIP), message))
@staticmethod
def hook_code(uc, address, size, user_data):
if address == Unico.HOOK_BASE + 4:
ESP = uc.reg_read(UC_X86_REG_ESP)
args = struct.unpack('<IIIIII', uc.mem_read(ESP+4, 24))
ret = 1
if Unico.LAST_IAT_NAME in Unico.IAT_HOOKS:
try:
eax = Unico.IAT_HOOKS[Unico.LAST_IAT_NAME](uc, args)
if isinstance(eax, (int, long)):
ret = eax
except Exception as e:
Unico.log(uc, "IAT hook error, name = %s, message = %s" % (Unico.LAST_IAT_NAME, e))
uc.mem_write(Unico.HOOK_BASE, struct.pack('<I', ret))
Unico.log(uc, "IAT function is being CALL, %s(%s) = 0x%x" % (Unico.LAST_IAT_NAME, ', '.join(map(hex, args)), ret))
elif address in Unico.EIP_HOOKS:
try:
neweip = Unico.EIP_HOOKS[address](uc, address, size)
if isinstance(neweip, (int, long)):
uc.reg_write(UC_X86_REG_EIP, neweip)
Unico.log(uc, "EIP hook at 0x%x (jump to 0x%x)" % (address, neweip))
else:
Unico.log(uc, "EIP hook at 0x%x" % address)
except Exception as e:
Unico.log(uc, "EIP hook error, address = 0x%x, message = %s" % (address, e))
elif address < 0x1000:
Unico.log(uc, "EIP is on NULL page, exiting...")
Unico.stop(uc)
@staticmethod
def hook_mem_access(uc, access, address, size, value, user_data):
if access == UC_MEM_READ:
if size == 4:
data = uc.mem_read(address, size)
value = struct.unpack('<I', data)[0]
Unico.log(uc, "Memory is being READ at 0x%x, data size = %u, data value = 0x%x" % (address, size, value))
else:
Unico.log(uc, "Memory is being READ at 0x%x, data size = %u" % (address, size))
if address in Unico.IAT_ENTRIES:
Unico.LAST_IAT_NAME = Unico.IAT_ENTRIES[address]
elif access == UC_MEM_WRITE:
if address < 0x1000:
print("\nWARNING: memory is being WRITE to NULL page, it may cause inaccurate results from here.\n")
Unico.log(uc, "Memory is being WRITE at 0x%x, data size = %u, data value = 0x%x" % (address, size, value))
elif access == UC_MEM_FETCH:
Unico.log(uc, "Memory is being FETCH at 0x%x, data size = %u, data value = 0x%x" % (address, size, value))
else:
raise Exception("Unexpected access type: %d" % access)
@staticmethod
def hook_mem_invalid(uc, access, address, size, value, user_data):
if access == UC_MEM_READ_UNMAPPED:
Unico.log(uc, "Missing memory is being READ at 0x%x, data size = %u, data value = 0x%x" % (address, size, value))
elif access == UC_MEM_WRITE_UNMAPPED:
Unico.log(uc, "Missing memory is being WRITE at 0x%x, data size = %u, data value = 0x%x" % (address, size, value))
else:
raise Exception("Unexpected access type: %d" % access)
uc.mem_map(address & ~0xFFF, 0x1000)
return True
@staticmethod
def hook_mem_fetch_unmapped(uc, access, address, size, value, user_data):
Unico.log(uc, "Missing memory is being FETCH at 0x%x, data size = %u, data value = 0x%x" % (address, size, value))
def run(self, pe_file, addr_start, addr_end):
with open(pe_file, 'rb') as f:
PE_IMAGE = f.read()
self.pe = pefile.PE(data=PE_IMAGE)
IMAGE_BASE = self.pe.OPTIONAL_HEADER.ImageBase
SIZE_OF_IMAGE = self.pe.OPTIONAL_HEADER.SizeOfImage
ENTRY_POINT = self.pe.OPTIONAL_HEADER.AddressOfEntryPoint
try:
mapped_image = self.pe.get_memory_mapped_image(ImageBase=IMAGE_BASE)
except AttributeError:
mapped_image = PE_IMAGE
mapped_size = (len(mapped_image) + 0x1000) & ~0xFFF
uc = Uc(UC_ARCH_X86, UC_MODE_32)
uc.mem_map(IMAGE_BASE, mapped_size)
uc.mem_write(IMAGE_BASE, mapped_image)
with open('pe_image_before.dump', 'wb') as f:
f.write(uc.mem_read(IMAGE_BASE, mapped_size))
uc.mem_map(self.STACK_LIMIT, self.STACK_BASE-self.STACK_LIMIT)
uc.mem_write(self.STACK_LIMIT, '\xdd' * (self.STACK_BASE-self.STACK_LIMIT))
uc.reg_write(UC_X86_REG_ESP, self.STACK_BASE-0x800)
uc.reg_write(UC_X86_REG_EBP, self.STACK_BASE-0x400)
uc.mem_map(Unico.HOOK_BASE, 0x1000)
uc.mem_write(Unico.HOOK_BASE, '\x00\x00\x00\x00\x8b\x04\x25' + struct.pack('<I', Unico.HOOK_BASE) + '\xc3') # mov eax, [HOOK_BASE]; ret
print("[+] Listing the imported symbols")
for entry in self.pe.DIRECTORY_ENTRY_IMPORT:
print(entry.dll)
for imp in entry.imports:
print(" 0x%x %s" % (imp.address, imp.name))
uc.mem_write(imp.address, struct.pack('<I', Unico.HOOK_BASE+4))
Unico.IAT_ENTRIES[imp.address] = imp.name
print("")
uc.hook_add(UC_HOOK_CODE, Unico.hook_code)
uc.hook_add(UC_HOOK_MEM_READ | UC_HOOK_MEM_WRITE | UC_HOOK_MEM_FETCH, Unico.hook_mem_access)
uc.hook_add(UC_HOOK_MEM_READ_UNMAPPED | UC_HOOK_MEM_WRITE_UNMAPPED, Unico.hook_mem_invalid)
uc.hook_add(UC_HOOK_MEM_FETCH_UNMAPPED, Unico.hook_mem_fetch_unmapped)
if not addr_start:
addr_start = IMAGE_BASE + ENTRY_POINT
if addr_end:
Unico.EXIT_ADDRESS = addr_end
else:
addr_end = Unico.EXIT_ADDRESS
uc.mem_map(Unico.EXIT_ADDRESS, 0x1000)
uc.mem_write(uc.reg_read(UC_X86_REG_ESP), struct.pack('<I', addr_end)) # store addr_end as return address
for init_hook in self.init_hooks:
init_hook(uc)
try:
uc.emu_start(addr_start, addr_end)
except UcError as e:
print("ERROR: %s" % e)
print("\n[+] Emulation done. Below is the CPU context")
print(">>> EAX = 0x%x" % uc.reg_read(UC_X86_REG_EAX))
print(">>> EBX = 0x%x" % uc.reg_read(UC_X86_REG_EBX))
print(">>> ECX = 0x%x" % uc.reg_read(UC_X86_REG_ECX))
print(">>> EDX = 0x%x" % uc.reg_read(UC_X86_REG_EDX))
print(">>> ESI = 0x%x" % uc.reg_read(UC_X86_REG_ESI))
print(">>> EDI = 0x%x" % uc.reg_read(UC_X86_REG_EDI))
print(">>> ESP = 0x%x" % uc.reg_read(UC_X86_REG_ESP))
print(">>> EBP = 0x%x" % uc.reg_read(UC_X86_REG_EBP))
print(">>> EIP = 0x%x" % uc.reg_read(UC_X86_REG_EIP))
print("\n[+] Write out pe_image.diff and stack.dump")
with open('pe_image_after.dump', 'wb') as f:
f.write(uc.mem_read(IMAGE_BASE, mapped_size))
with open('stack.dump', 'wb') as f:
f.write(uc.mem_read(self.STACK_LIMIT, self.STACK_BASE-self.STACK_LIMIT))
os.system("bash -c 'diff -u <(xxd pe_image_before.dump) <(xxd pe_image_after.dump) >pe_image.diff'")
if __name__ == '__main__':
if len(sys.argv) < 2:
print("Usage: python %s PE_FILE [ADDR_START ADDR_END]" % sys.argv[0], file=sys.stderr)
sys.exit(1)
pe_file = sys.argv[1]
addr_start = int(sys.argv[2], 16) if len(sys.argv) >= 3 else None
addr_end = int(sys.argv[3], 16) if len(sys.argv) >= 4 else None
unico = Unico()
unico.run(pe_file, addr_start, addr_end)