DASCTF 2024 10月 Reverse 完成笔记 附题目
题目链接:
https://github.com/Airrcat/long_long/tree/main/DASCTF_2024_10
ezre
查PE
32位无壳
开始分析
看起来很像加壳了
字符串未有暴露信息，但是段中有一个themida
发现是一个壳，直接去找脱壳机
一些脱壳工具（Magicmida)是动态启动后脱壳，会被程序的反调试检查到
后来发现了这个静态脱壳工具
unlicense
PS C:\Users\Songs\Desktop\DASCTF10月\tempdir\REVERSE附件> .\unlicense.exe '.\ezre.exe'
INFO - Detected packer version: 3.x
frida-agent: Setting up OEP tracing for "ezre.exe"
frida-agent: Exception handler registered
frida-agent: OEP found (thread #22604): 0x8a18fe
INFO - OEP reached: OEP=0x8a18fe BASE=0x8a0000 DOTNET=False
INFO - Looking for the IAT...
INFO - Performing linear scan in data sections...
INFO - Looking for wrapped imports in code sections...
INFO - Potential import wrappers found: 15
INFO - IAT found: 0x8a3000-0x8a300b
INFO - Resolving imports ...
INFO - Imports resolved: 43
INFO - Fixed IAT at 0x8a3000, size=0xc5
INFO - Dumping PE with OEP=0x8a18fe ...
INFO - Fixing dump ...
INFO - Rebuilding PE ...
INFO - Output file has been saved at 'unpacked_ezre.exe'
main函数默认反编译不了，有个花
处理一下把jmp地址的e8 patch成90即可
上头一个cipher，底下两个处理函数然后就比较了
处理函数也有花，记得处理
第一个是魔改rc4，
重命名一下
第二个是魔改xtea
外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传
要注意的是，魔改xtea在执行的时候，地址是byte +1+1并patch回去，也就是cipher的[0:4]~ [4:8] [1:5] ~ [4~9]…
因此最后得倒着运算
exp:
# 普通的rc4解密
from ctypes import *
key = "th0s_i0_ke9"
S = []
# 期待输入存储字节型的列表。
# 预期输出存储0~256下标的列表。
def rc4_init(S, K): # S盒初始化置换,K为密钥
j = 0
S.clear() # init的时候重置sbox
for i in range(256):
S.append(i)
for i in range(256):
try:
j = (j + S[i] + ord(K[i % len(K)])) % 256
except:
j = (j + S[i] + K[i % len(K)]) % 256
S[i], S[j] = S[j], S[i] # 交换S[i],S[j]
def rc4_xor(S, D):
i = j = 0
result = []
for a in D:
i = (i + 1) % 256
j = (j + S[i]) % 256
S[i], S[j] = S[j], S[i]
try:
k = ord(a) + (S[(S[i] + S[j]) % 256] ^ 0x33)
except:
k = a + (S[(S[i] + S[j]) % 256] ^ 0x33)
result.append(k)
return result
def rc4_xor2(S, D):
i = j = 0
result = []
for a in D:
i = (i + 1) % 256
j = (j + S[i]) % 256
S[i], S[j] = S[j], S[i]
try:
k = ord(a) - (S[(S[i] + S[j]) % 256] ^ 0x33)
except:
k = (a - (S[(S[i] + S[j]) % 256] ^ 0x33)) & 0xff
result.append(k)
return result
def encrypt(v, key):
v0, v1 = c_uint32(v[0]), c_uint32(v[1])
delta = 0x9E3779B8
rounds = 33
total = c_uint32(0x66778899)
for i in range(rounds):
v0.value += (((v1.value << 5) ^ (v1.value >> 6)) +
v1.value) ^ (total.value + key[total.value & 3])
total.value += delta
v1.value += (((v0.value << 4) ^ (v0.value >> 5)) +
v0.value) ^ (total.value + key[(total.value >> 11) & 3])
return v0.value, v1.value
def decrypt(v, key):
v0, v1 = c_uint32(v[0]), c_uint32(v[1])
delta = 0x9E3779B8
rounds = 33
total = c_uint32(delta * rounds+0x66778899)
for i in range(rounds):
v1.value -= (((v0.value << 4) ^ (v0.value >> 5)) +
v0.value) ^ (total.value + key[(total.value >> 11) & 3])
total.value -= delta
v0.value -= (((v1.value << 5) ^ (v1.value >> 6)) +
v1.value) ^ (total.value + key[total.value & 3])
return v0.value, v1.value
rc4_init(S, key)
cipher = rc4_xor(S, "12341234")
print(cipher)
value = [0]*2
value[0] = int.from_bytes(bytes(cipher[0:4]), 'little')
value[1] = int.from_bytes(bytes(cipher[4:8]), 'little')
print(encrypt(value, [0x6e982837, 0x44332211, 0x11223344, 0x3728986e]))
cipher = decrypt([1690332198, 2660953638], [
0x6e982837, 0x44332211, 0x11223344, 0x3728986e])
rc4_init(S, key)
flag = rc4_xor2(S, cipher[0].to_bytes(4, 'little') +
cipher[1].to_bytes(4, 'little'))
print(flag)
# 标准xtea
if __name__ == "__main__":
cipher = b'P\xd4\xc8\xc4\x8f\x84@\xeb2\x81\x8f\x85l\xb2+\x06\xbf\x055].\xe3}F\x8d5\x01p:\x80\x81\xc5\xe6q\xd3\xd6Pio\xe2nx\x14\xd8'
cipher = list(cipher)
print("cypher len:", len(cipher))
print(f"cipher :{cipher}")
# 四个key，每个是32bit，即密钥长度为128bit
tea_key = [0x6e982837, 0x44332211, 0x11223344, 0x3728986e]
flag = b""
for i in range(36, -1, -1):
value = [0]*2
value[0] = int.from_bytes(bytes(cipher[i:i+4]), 'little')
value[1] = int.from_bytes(bytes(cipher[i+4:i+8]), 'little')
value = decrypt(value, tea_key)
# print(cipher)
for l in range(4):
cipher[i+l] = value[0].to_bytes(4, 'little')[l]
cipher[i+4+l] = value[1].to_bytes(4, 'little')[l]
# print(cipher)
print(f"after xtea:{cipher}")
rc4_init(S, key)
flag = rc4_xor2(S, cipher)
print(f"after rc4:{bytes(flag)}")
"""
Data is : 0x12345678 0x78563412
Encrypted data is : 0xae685ec7 0x59af4238
Decrypted data is : 0x12345678 0x78563412
"""
[226, 192, 169, 129, 151, 101, 142, 195]
(1690332198, 2660953638)
[49, 50, 51, 52, 49, 50, 51, 52]
cypher len: 44
cipher :[80, 212, 200, 196, 143, 132, 64, 235, 50, 129, 143, 133, 108, 178, 43, 6, 191, 5, 53, 93, 46, 227, 125, 70, 141, 53, 1, 112, 58, 128, 129, 197, 230, 113, 211, 214, 80, 105, 111, 226, 110, 120, 20, 216]
after xtea:[245, 207, 201, 144, 186, 121, 214, 227, 81, 34, 213, 44, 80, 233, 246, 153, 113, 77, 122, 222, 255, 68, 197, 171, 25, 55, 172, 232, 114, 182, 164, 14, 147, 134, 75, 195, 85, 54, 116, 25, 54, 162, 175, 69]
after rc4:b'DASCTF{Th1l_t8e1a_rc4_l8s_s8o_int9r3es4t1ng}'
ezelf
查pe
64位
打开一看ollvm
试试D810
效果难以接受
deflat还可以，使用deflat的flat_control_flow
cipher1
cipher2
第一个加密是个rc4+xxtea
这里经过deflat后代码结构可能会发生变化，比如xxtea的循环结构这里就不太对，可以参照源文件或者用ollvm解混淆的版本。
我大致看了下基本的结构，参数没变化，rounds16、n8.稍特别一点的是&7,&7这里实际应该是&n，一个参考的xxtea如：
每个n的小循环里最后一轮需要一个v[0]参数，而&n能够直接在让p走一个循环，即y = v[(p+1)&n]可以在0~n内完成y从v[1]到v[n-1]后再到v[0]的变化。
部分变量优化后如图：
猜测是xxtea key，动调可对比
这个应该是rc4 key，盲猜
试着解一下第一个cipher，会发现xxtea能出东西，然后rc4没什么东西，实际调试发现rc4好像暂时用不到？
xxtea:
from ctypes import *
import dis
def MX(z, y, total, key, p, e):
temp1 = (z.value >> 5 ^ y.value << 2) + (y.value >> 3 ^ z.value << 4)
temp2 = (total.value ^ y.value) + (key[(p & 3) ^ e.value] ^ z.value)
return c_uint32(temp1 ^ temp2)
def encrypt(n, v, key):
delta = 0x11451400
rounds = 16
total = c_uint32(0)
z = c_uint32(v[n-1])
e = c_uint32(0)
while rounds > 0:
total.value += delta
e.value = (total.value >> 2) & 3
for p in range(n-1):
y = c_uint32(v[p+1])
v[p] = c_uint32(v[p] + MX(z, y, total, key, p, e).value).value
z.value = v[p]
y = c_uint32(v[0])
v[n-1] = c_uint32(v[n-1] + MX(z, y, total, key, n-1, e).value).value
z.value = v[n-1]
rounds -= 1
return v
def decrypt(n, v, key):
delta = 0x11451400
rounds = 16
total = c_uint32(rounds * delta)
y = c_uint32(v[0])
e = c_uint32(0)
while rounds > 0:
e.value = (total.value >> 2) & 3
for p in range(n-1, 0, -1):
z = c_uint32(v[p-1])
v[p] = c_uint32((v[p] - MX(z, y, total, key, p, e).value)).value
y.value = v[p]
z = c_uint32(v[n-1])
v[0] = c_uint32(v[0] - MX(z, y, total, key, 0, e).value).value
y.value = v[0]
total.value -= delta
rounds -= 1
return v
# test
if __name__ == "__main__":
# 该算法中每次可加密不只64bit的数据，并且加密的轮数由加密数据长度决定
cipher = b'\xb4\xb5ZB\xa6y\x0b\xac\x0e#x\xde\xe1-\xc6\x1d\xbb)\x8c\xe2\x94\xfe\x14\xd9\xaa\x03\xe3\x8a\x14\x92\x1cd'
# cipher = b'01234567890123456790123465789012'
key = [0xb, 0x2d, 0xe, 0x309]
v = [0] * (len(cipher)//4)
print("cipher len:", len(cipher))
# 密文cipher格式转化，从字节转成int
for i in range(0, len(cipher), 4):
if 'bytes' in str(type(cipher)):
v[i//4] = int.from_bytes(cipher[i:i+4], 'little')
elif 'list' in str(type(cipher)):
try:
v[i//4] = (ord(cipher[i]) | (ord(cipher[i+1]) << 8) |
(ord(cipher[i+2]) << 16) | (ord(cipher[i+3]) << 24))
except:
v[i//4] = ((cipher[i]) | ((cipher[i+1]) << 8) |
((cipher[i+2]) << 16) | ((cipher[i+3]) << 24))
k = key
n = len(v)
for i in v:
print(hex(i), end=" ")
print()
for i in k:
print(hex(i), end=" ")
print()
res = decrypt(8, v, k)
flag = b''
for i in res:
flag += i.to_bytes(4, 'little')
print(flag)
之后翻到了疑似rc4加密的函数
int *__fastcall sub_403A90(int *a1)
{
int *result; // rax
_QWORD v2[10]; // [rsp+0h] [rbp-B0h] BYREF
int i; // [rsp+54h] [rbp-5Ch]
int *v4; // [rsp+58h] [rbp-58h]
int **v5; // [rsp+60h] [rbp-50h]
int *v6; // [rsp+68h] [rbp-48h]
int *v7; // [rsp+70h] [rbp-40h]
int v8; // [rsp+78h] [rbp-38h]
bool v9; // [rsp+7Fh] [rbp-31h]
int *v10; // [rsp+80h] [rbp-30h]
int v11; // [rsp+8Ch] [rbp-24h]
int v12; // [rsp+90h] [rbp-20h]
int v13; // [rsp+94h] [rbp-1Ch]
int *v14; // [rsp+98h] [rbp-18h]
_DWORD v15[2]; // [rsp+A0h] [rbp-10h] BYREF
int *v16; // [rsp+A8h] [rbp-8h]
__int64 savedregs; // [rsp+B0h] [rbp+0h] BYREF
v2[9] = a1;
v5 = (int **)&v2[-2];
i = 1498122419;
v6 = (int *)&savedregs;
v7 = v15;
v4 = a1;
*v5 = (int *)v2[8];
*v4 ^= pbox[0];
*v7 = 1;
for ( i = -391087700; ; i = -391087700 )
{
v8 = *v7;
v9 = v8 <= 16;
i = 1128705075;
if ( v8 > 16 )
break;
v10 = v4;
i = -211233099;
*v6 = *v4;
v11 = **v5;
v12 = dword_40A500[(unsigned __int8)BYTE2(*v6)] + sbox[HIBYTE(*v6)];
v13 = dword_40A900[(unsigned __int8)BYTE1(*v6)];
v14 = &sbox[(unsigned __int8)*v6 + 768];
i = 822856190;
*v4 = (*v14 + v13) ^ v12 ^ v11;
**v5 = *v6;
i = 1380722011;
v15[0] = *v7 + 1;
*v7 = v15[0];
}
v15[1] = dword_40A0E4;
i = 2118140716;
**v5 ^= dword_40A0E4;
*v6 = *v4;
v16 = *v5;
i = 1584127650;
*v4 = *v16;
result = *v5;
**v5 = *v6;
return result;
}
其接收了前面的rc4_init吐出来的参数，但这里可以看出来并不是rc4
结合题目的提示，我们可以猜测是blowfish加密
这里的加密部分略微魔改
left一开始异或了pbox[0]，而在结束时不再异或pbox[N+1]，同时每一轮里不再异或pbox，等于说pbox只异或了一次，循环内全程异或sbox，约等于rc4的加密模式
这里的加密差不多是：（xl即left，这里的left、right命名参考了网上blowfish博客里的命名）
简单逆向分析一下
从正向来看，next_left是由left+right运算得来，而next_right存储了本轮的初始left，并不多做运算，算一个状态存储
即:
left+right->next_left
left->next_right
因此在一轮中，可以很直接从next_right得到left，进而由left+next_left求得right即：
next_right->left
next_left+left->right
ps:需要注意的是，encrypt最后交换了一次left和right，同时头尾还分别异或了一次pbox[0]和pbox[18]
算法完整实现：
sbox = [[0x00000179, 0x000001BE, 0x243F6B50, 0x00000164, 0x243F6ABF, 0x243F6B94, 0x00000175, 0x243F6B20, 0x0000009A, 0x00000056, 0x243F6B1F, 0x000001E3, 0x243F6BE8, 0x243F6A16, 0x000000F7, 0x243F6B88, 0x000001BD, 0x000001BC, 0x243F6A41, 0x000000FB, 0x243F6B18, 0x243F6A04, 0x0000003D, 0x243F6B22, 0x000000F0, 0x00000042, 0x243F6BF5, 0x000000E0, 0x243F6A7F, 0x243F6A9A, 0x0000009C, 0x243F6A8C, 0x000001AD, 0x00000116, 0x243F6AF7, 0x000001C0, 0x243F6BBD, 0x243F6A2F, 0x0000016A, 0x0000079B, 0x243F6D8B, 0x000001CA, 0x000006A3, 0x243F6C37, 0x243F6A65, 0x243F6A6F, 0x0000018D, 0x00000617, 0x243F6DEA, 0x00000059, 0x000007CB, 0x243F6D22, 0x243F6B05, 0x243F6A2B, 0x0000007A, 0x00000717, 0x243F6CC1, 0x000001A2, 0x000007D3, 0x243F6D93, 0x243F6A5A, 0x243F6A5C, 0x00000041, 0x000007B6, 0x243F6D71, 0x00000139, 0x000006B7, 0x243F6D90, 0x243F6A2F, 0x243F6BF5, 0x00000026, 0x0000069D, 0x243F6D9A, 0x000001BF, 0x00000709, 0x243F6C54, 0x243F6AE9, 0x243F6BF7, 0x00000054, 0x00000752, 0x243F6C2C, 0x000000FA, 0x0000073A, 0x243F6C82, 0x243F6BB7, 0x243F6A09, 0x000000DA, 0x000007AF, 0x243F6C34, 0x000001E8, 0x000006E6, 0x243F6CCC, 0x243F6B05, 0x243F6AB7, 0x00000196, 0x00000693, 0x243F6C4D, 0x0000013B, 0x00000734, 0x243F6D31, 0x243F6B96, 0x243F6BD7, 0x00000110, 0x000007C2, 0x243F6DA1, 0x00000146, 0x00000795, 0x243F6C7A, 0x243F6A1F, 0x243F6A52, 0x00000087, 0x00000645, 0x243F6D74, 0x00000199, 0x00000707, 0x243F6C52, 0x243F6B1C, 0x243F6B6C, 0x00000138, 0x000006D7, 0x243F6D5C, 0x000000CA, 0x0000077A, 0x243F6DC3, 0x243F6A68, 0x243F6BC7, 0x0000008F, 0x000006CA, 0x243F6D11, 0x000001F2, 0x0000076E, 0x243F6CA9, 0x243F6A75, 0x243F6BC9, 0x00000135, 0x0000078A, 0x243F6D76, 0x00000013, 0x00000780, 0x243F6C46, 0x243F6BEB, 0x243F6A5B, 0x000000EB, 0x00000795, 0x243F6D4B, 0x0000004A, 0x000006C0, 0x243F6DDA, 0x243F6B71, 0x243F6A17, 0x000001E3, 0x00000667, 0x243F6C1B, 0x000000AF, 0x0000062A, 0x243F6DDE, 0x243F6B53, 0x243F6B4F, 0x0000019E, 0x00000613, 0x243F6D53, 0x000001EC, 0x0000076B, 0x243F6D78, 0x243F6B84, 0x243F6A1C, 0x00000009, 0x000006D8, 0x243F6CD1, 0x0000012B, 0x00000641, 0x243F6D10, 0x243F6A1C, 0x243F6A61, 0x00000104, 0x00000646, 0x243F6D6D, 0x0000000A, 0x0000061F, 0x243F6D92, 0x243F6A81, 0x243F6AE0, 0x0000017D, 0x00000666, 0x243F6C1D, 0x0000017B, 0x000007E6, 0x243F6C39, 0x243F6BE1, 0x243F6B23, 0x000000CA, 0x000006E5, 0x243F6D5A, 0x00000034, 0x0000079C, 0x243F6C18, 0x243F6B0F, 0x243F6AB2, 0x000000FC, 0x00000702, 0x243F6D7A, 0x0000005E, 0x000007D8, 0x243F6D9E, 0x243F6B03, 0x243F6A3A, 0x00000137, 0x00000619, 0x243F6C1C, 0x00000070, 0x0000071E, 0x243F6CB7, 0x243F6A42, 0x243F6A37, 0x00000150, 0x000007BB, 0x243F6D5A, 0x00000075, 0x0000071A, 0x243F6DCA, 0x243F6A48, 0x243F6B5B, 0x000001AA, 0x0000069C, 0x243F6D9D, 0x0000001B, 0x00000720, 0x243F6D57, 0x243F6B10, 0x243F6BE8, 0x000000FD, 0x00000656, 0x243F6CF4, 0x00000047, 0x00000686, 0x243F6C0B, 0x243F6BD9, 0x243F6BD8, 0x00000130, 0x000007DE, 0x243F6D74, 0x00000002, 0x000007F3, 0x243F6D4B, 0x243F6A41, 0x243F6B50, 0x00000033, 0x00000624, 0x243F6DC5, 0x00000133, 0x00000645, 0x243F6DCC, 0x243F6B43, 0x243F6B41, 0x000000E9, 0x00000753], [0x243F6D0A, 0x000000D7, 0x243F6A70, 0x243F6CA6, 0x000006A7, 0x243F6B0C, 0x000001B5, 0x00000760, 0x243F6CEB, 0x000000EE, 0x243F6ADE, 0x243F6D02, 0x00000743, 0x243F6A5C, 0x000000DC, 0x000006D9, 0x243F6DC6, 0x000001DD, 0x243F6A12, 0x243F6DFF, 0x00000732, 0x243F6B80, 0x000001AC, 0x000007D5, 0x243F6D06, 0x000000C5, 0x243F6B51, 0x243F6D2B, 0x000006DC, 0x243F6A2D, 0x00000055, 0x000006FC, 0x243F6D7D, 0x000001D0, 0x243F6AA3, 0x243F6C75, 0x0000061A, 0x243F6A2A, 0x00000101, 0x000006F0, 0x243F6C4D, 0x00000138, 0x243F6A75, 0x243F6CA9, 0x000007FC, 0x243F6B27, 0x00000123, 0x000006C5, 0x243F6D32, 0x0000003B, 0x243F6A23, 0x243F6CB3, 0x00000686, 0x243F6B1A, 0x00000107, 0x00000608, 0x243F6DFD, 0x000001E8, 0x243F6BBB, 0x243F6D08, 0x0000062B, 0x243F6B94, 0x000000A1, 0x0000075A, 0x243F6CDC, 0x000000FB, 0x243F6B69, 0x243F6DD6, 0x00000655, 0x243F6ADD, 0x000000DD, 0x000007DC, 0x243F6DBD, 0x00000068, 0x243F6B0C, 0x243F6C95, 0x00000745, 0x243F6B15, 0x000001C9, 0x00000754, 0x243F6D3A, 0x0000003D, 0x243F6B34, 0x243F6DD6, 0x000006E1, 0x243F6A4E, 0x0000004E, 0x00000776, 0x243F6D6C, 0x000000F3, 0x243F6B5D, 0x243F6CEF, 0x000007F9, 0x243F6B68, 0x000001D0, 0x000007BB, 0x243F6DC9, 0x00000164, 0x243F6A2B, 0x243F6C43, 0x00000670, 0x243F6A8A, 0x0000007B, 0x000006DC, 0x243F6DAD, 0x000000FC, 0x243F6B51, 0x243F6CE4, 0x00000760, 0x243F6AF2, 0x00000004, 0x000006B5, 0x243F6D8E, 0x0000018C, 0x243F6B3C, 0x243F6D44, 0x0000071A, 0x243F6ADD, 0x0000002E, 0x0000075A, 0x243F6DCE, 0x00000120, 0x243F6BFB, 0x243F6D9F, 0x000007B1, 0x243F6BCC, 0x00000063, 0x0000068A, 0x243F6C2D, 0x00000034, 0x243F6A0C, 0x243F6D0A, 0x000006D7, 0x243F6B8B, 0x00000112, 0x000006EE, 0x243F6DF2, 0x000000AF, 0x243F6A7C, 0x243F6C01, 0x00000628, 0x243F6B11, 0x0000005D, 0x00000657, 0x243F6CE0, 0x0000008A, 0x243F6B43, 0x243F6C86, 0x00000682, 0x243F6B31, 0x0000003B, 0x000007A5, 0x243F6CF5, 0x00000058, 0x243F6B6B, 0x243F6DA1, 0x00000657, 0x243F6B40, 0x0000008E, 0x000006F1, 0x243F6C5E, 0x00000031, 0x243F6A50, 0x243F6CBD, 0x00000721, 0x243F6BF3, 0x0000019E, 0x00000766, 0x243F6C8A, 0x0000008D, 0x243F6B1B, 0x243F6C2B, 0x0000076D, 0x243F6BCA, 0x0000019D, 0x000007BD, 0x243F6C64, 0x000001F6, 0x243F6B7C, 0x243F6D1B, 0x00000735, 0x243F6BB3, 0x000000B0, 0x000006B1, 0x243F6D6A, 0x000000DD, 0x243F6BC6, 0x243F6CC0, 0x000007E2, 0x243F6A78, 0x0000004B, 0x00000639, 0x243F6D29, 0x000001DF, 0x243F6BB1, 0x243F6CD2, 0x000006E6, 0x243F6B54, 0x000001E0, 0x000007CC, 0x243F6C8D, 0x000000C7, 0x243F6B33, 0x243F6C98, 0x00000666, 0x243F6B02, 0x000001C8, 0x0000071D, 0x243F6CC3, 0x000000BF, 0x243F6AA3, 0x243F6DE8, 0x000006E9, 0x243F6BEF, 0x000000DB, 0x00000660, 0x243F6DB8, 0x000001DD, 0x243F6BD5, 0x243F6C87, 0x0000072C, 0x243F6BAA, 0x000001F5, 0x00000663, 0x243F6DB3, 0x00000069, 0x243F6A29, 0x243F6C6A, 0x000006EB, 0x243F6B17, 0x00000137, 0x0000071B, 0x243F6CF1, 0x00000193, 0x243F6A00, 0x243F6D1A, 0x000006FF, 0x243F6B0E, 0x00000021, 0x000007B1, 0x243F6D28, 0x000001BE, 0x243F6BEA, 0x243F6DB3, 0x00000787, 0x243F6B74, 0x00000104, 0x00000736, 0x243F6CBE, 0x00000089, 0x243F6A05, 0x243F6C0C, 0x000007AE, 0x243F6A08, 0x00000142, 0x000006B0], [0x243F6DD9, 0x0000017F, 0x243F6A57, 0x0000012C, 0x243F6A21, 0x243F6B8B, 0x000000C6, 0x000018C5, 0x243F6ACE, 0x243F6C4B, 0x0000067A, 0x243F6A2B, 0x243F6F63, 0x00001C37, 0x000019D3, 0x00000114, 0x00001C6A, 0x243F73C0, 0x00001819, 0x243F740E, 0x243F7446, 0x243F73F7, 0x243F7319, 0x00000004, 0x243F683B, 0x243F7154, 0x243F6CD1, 0x00001B40, 0x000007D2, 0x00001A18, 0x243F6047, 0x000019FF, 0x243F6828, 0x0000120F, 0x243F788D, 0x00000358, 0x243F755C, 0x00001D78, 0x243F6EC0, 0x243F7510, 0x00000CB6, 0x00000259, 0x243F6AC6, 0x243F605F, 0x000010D7, 0x243F7496, 0x000006CA, 0x00001B44, 0x243F77E8, 0x243F750D, 0x00001E97, 0x243F74E5, 0x00001F57, 0x00000388, 0x000019A3, 0x243F6DF6, 0x243F74D4, 0x00000BD2, 0x243F782D, 0x00001DE7, 0x243F7596, 0x243F6E9E, 0x000005B8, 0x243F64B7, 0x243F7743, 0x243F79C4, 0x00000D70, 0x243F7230, 0x00000167, 0x00000FD2, 0x243F67CF, 0x0000028A, 0x243F6DAA, 0x00000914, 0x00000C6C, 0x000018C1, 0x243F6FD0, 0x00000D73, 0x243F7FFB, 0x000005DB, 0x243F728A, 0x0000109A, 0x243F7838, 0x243F6A4F, 0x00000590, 0x243F60EC, 0x00001ECE, 0x000018AE, 0x243F7780, 0x243F6C0D, 0x243F6944, 0x00001F7E, 0x243F6C54, 0x00001A3C, 0x243F69BD, 0x00001C8C, 0x243F6735, 0x243F6B1C, 0x00000E62, 0x243F6BAC, 0x243F77D8, 0x00000610, 0x00001C91, 0x243F72D8, 0x000002C3, 0x000006B5, 0x243F6EFD, 0x000004FA, 0x243F7964, 0x000000C1, 0x243F6B31, 0x00000FC6, 0x243F6599, 0x243F6FC0, 0x000016D1, 0x243F7E5C, 0x0000161A, 0x000001C2, 0x243F72FB, 0x00001AF6, 0x243F630A, 0x243F677E, 0x243F75A2, 0x0000008F, 0x243F612D, 0x000005C4, 0x00001739, 0x00001A95, 0x243F7163, 0x00001517, 0x243F73A9, 0x243F7B9F, 0x243F6605, 0x243F789F, 0x243F78D9, 0x243F6481, 0x00000407, 0x00001402, 0x243F76DD, 0x243F6C84, 0x243F65DE, 0x0000085E, 0x243F613E, 0x00001BE3, 0x243F6A7D, 0x000016B9, 0x00001A72, 0x243F7DE6, 0x243F6E50, 0x243F6582, 0x000001B3, 0x243F7A6A, 0x00001A0D, 0x0000195F, 0x243F6CEE, 0x243F6B4B, 0x00001517, 0x00000F71, 0x00001733, 0x00001304, 0x243F6D4A, 0x243F73EC, 0x000014C1, 0x00000D60, 0x00001A0A, 0x243F65C5, 0x243F6362, 0x000007DF, 0x0000090D, 0x000002B4, 0x243F7F3E, 0x00000E12, 0x243F7DB5, 0x243F709F, 0x243F712C, 0x243F638E, 0x243F77A0, 0x00000089, 0x243F7B1A, 0x00000763, 0x243F7C76, 0x243F6F14, 0x243F7626, 0x000009C4, 0x243F77BC, 0x243F6C86, 0x243F7FD2, 0x00000600, 0x243F76A8, 0x243F6F27, 0x0000047F, 0x000006DE, 0x243F78B8, 0x243F6DC0, 0x00001238, 0x243F7FF0, 0x243F66DE, 0x243F6E3F, 0x00000860, 0x000019ED, 0x000007B5, 0x00000C92, 0x243F70FE, 0x243F6DB7, 0x243F7049, 0x243F6BFF, 0x243F6C8F, 0x0000017F, 0x243F7510, 0x243F7C75, 0x00001AE7, 0x000015B8, 0x000009F6, 0x0000038E, 0x243F614F, 0x243F7A8B, 0x243F696F, 0x00001871, 0x243F7670, 0x243F699C, 0x243F7707, 0x243F6622, 0x243F643A, 0x000017B5, 0x0000170B, 0x00001405, 0x243F7819, 0x243F6A96, 0x243F6815, 0x00000892, 0x243F7699, 0x243F7FB6, 0x243F7F3F, 0x00000EF4, 0x243F777E, 0x000005C3, 0x0000006B, 0x00001984, 0x00001B5F, 0x000010CC, 0x00000155, 0x243F7738, 0x00001A56, 0x00000709, 0x00001DE0, 0x243F6CA6, 0x243F7F68, 0x243F7230, 0x00001280, 0x243F6E81, 0x00001078, 0x00001D32, 0x243F68BD, 0x00000818, 0x243F6311, 0x243F675C], [0x243F78C4, 0x243F753E, 0x243F736D, 0x243F75C4, 0x243F7B49, 0x243F6182, 0x243F7736, 0x487EDA66, 0x6C41AE95, 0x00000ED2, 0x243F68E7, 0x243F51D9, 0x243F4D7E, 0x00001881, 0x487EFA5B, 0x243F50D5, 0x00003A76, 0x00004BFD, 0x000042CC, 0x243F5740, 0x4881D4F4, 0x243F3454, 0x487E9D94, 0x24C0BCA1, 0x24C0A52D, 0x6C41ECE3, 0x243FAFD6, 0x00FFCA25, 0x24C0A4AC, 0x6C418D7F, 0x0000322D, 0x24C0BC9A, 0xB4418102, 0x243F458F, 0x90FE5500, 0xFC3F4317, 0xD8003DE3, 0xD880B029, 0xD88067D2, 0xFD414299, 0x6D3F9C8A, 0x680273CD, 0x4C3D6B79, 0x907ED9F3, 0xD8005409, 0x4C3D9464, 0x04BC53DA, 0x9100426C, 0x01805807, 0x4CC294D4, 0x91FD752E, 0xB4BE1640, 0x48010E11, 0xE3032424, 0xE37C4473, 0x48012FF8, 0x48014B78, 0xE37C0627, 0x8B7EECC2, 0x6C3EE5FB, 0xFC3FB6E8, 0xAB02DFA6, 0x1E3DA9CE, 0xB3FA7DB4, 0x97C4E4E9, 0x6EBFFAE7, 0x3DBE4086, 0xDB3BD655, 0x9180AE11, 0x74402D92, 0xE4C0B226, 0x417E59CF, 0x2D3E9A98, 0x74C0161F, 0x3CBED7FF, 0x65404821, 0xBA7D1866, 0x453CFEF2, 0x4EF981B4, 0x63065FB2, 0xBBF9EB62, 0x6604C332, 0xC1409279, 0xCE3B5B30, 0xA27A27C0, 0xA402D0DB, 0xA402A165, 0x6A38B205, 0x9E4030AD, 0x8143D678, 0x81BCEF4A, 0x2A01BF61, 0xC33CB9D4, 0xA58387B8, 0xA5839152, 0x5C7FE1E9, 0x79BE6BC7, 0xD6FEA602, 0x9E80BA77, 0xD4BF5F2C, 0x7403D770, 0x63C1B0E9, 0xE683FB24, 0x8806F26D, 0x313A14C9, 0xF0FDD92D, 0x257EF53D, 0x6FFBD242, 0x93BB1CE6, 0x23F9C6D3, 0x40B9FEED, 0x247C6C25, 0xA5BE678D, 0xD1056FF7, 0x41047DD2, 0x3339C309, 0x2084BA70, 0x94B8F697, 0xBFBB7643, 0xCD40FE71, 0x18C7E438, 0x9FFA5966, 0x6DFBE110, 0xD9C73A1C, 0x8E8409F9, 0x457A62B9, 0x61BB67C5, 0xA34394F8, 0x133EC8BB, 0xD4044FDD, 0x37C2F42A, 0xD27CB5F5, 0xFA4385E6, 0xDB463532, 0xE77C83DB, 0x627AF59D, 0xB2BEF94C, 0x9538FC45, 0x94C780B8, 0xCE7D1809, 0x3600DB13, 0xD4043B07, 0x823978D3, 0xC941E157, 0xCF3B9C59, 0x1BBE0DBF, 0x45B82831, 0x2FBA2022, 0xBA404B95, 0xFBC6E8E9, 0x6BB97E01, 0xFE856CA4, 0xE0F86BE2, 0x417CFCC8, 0x593E2226, 0xCFC24E4C, 0x7A0120B8, 0x497C2328, 0xDABA34D7, 0xE4FEF97A, 0x30F9F8F0, 0xA3008CE8, 0x53042AB9, 0xDCC61F48, 0x413C8D0D, 0xF58629DF, 0xFE86F2F4, 0x9D7DC3B9, 0x78C46C05, 0x0F0042A4, 0xE0C6DC69, 0xF03965FE, 0x0D392FF5, 0x96BD28CC, 0x5007B425, 0xB23A094E, 0x78C58334, 0x554534AD, 0x76BB974C, 0xCE463A66, 0x503E5C7E, 0xECC6E9D5, 0xB2BC9A65, 0x7EFA2172, 0x9CBC1C30, 0x8ABB77E4, 0xC405B76D, 0x957E308C, 0x33C63316, 0x4538C965, 0x9E7DEEC8, 0x52429D62, 0x12477299, 0x5B06AB74, 0xE230A2BD, 0xECC0E3FC, 0x3BBB450A, 0xDD08DCAF, 0x85310C1D, 0xD6BF06E5, 0x8EFA5117, 0x008ED76D, 0xE60CBBDB, 0x153F2D29, 0x40036983, 0xCECDFD2E, 0xFBB1B2D1, 0x7545E297, 0xE8358074, 0x8DF723F0, 0xA23629D2, 0x5FCBD770, 0x94BB0B3F, 0xCC884977, 0x8DF5FC17, 0xA2F3EFA9, 0x0032BD44, 0x454EB69F, 0x52361CBE, 0x284A2C50, 0x808DB6EF, 0x100C2C87, 0xC231A257, 0xF649F162, 0x34744D4A, 0xA1C8D102, 0xA4BB9290, 0xD0889351, 0x880D0584, 0xD947E8F7, 0x6773EB5C, 0x150E2584, 0x0F75E358, 0xE5F772E0, 0x9F383204, 0x75F4A824, 0x20B41979, 0x7141F2E2, 0x2889B099, 0x3A48D877, 0x0D8FEB17, 0xBB82ED5A, 0x137E775D, 0x1489F19C, 0x1D4E3534, 0xEBF75BE4, 0x638042BA, 0x88B12A5F, 0x1B731B37, 0x7340DC9D, 0x86BF7902, 0x310D3C12, 0x00F6DEFE, 0xFF3B2E2F, 0x2748AF3A, 0xC6BE79AE]
]
cipher = [0x8DF0B770, 0x4B1EB28E, 0x73C65C1C, 0x53DE48FD,
0x982EDF34, 0xD8229123, 0x90271182, 0x1F4271E7]
flag = b''
for i in range(0, len(cipher), 2):
left = cipher[i+1]
right = cipher[i] ^ 0x243F6BA8
for l in range(16):
prev_left = right
pref_right = left ^ (sbox[0][right >> 24] + sbox[1][right >> 16 & 0xff]) ^ (
sbox[2][right >> 8 & 0xff] + sbox[3][right & 0xff])
left = prev_left
right = pref_right & 0xffffffff
left ^= 0x125
flag += left.to_bytes(4, 'little') + right.to_bytes(4, 'little')
print(flag)
ezAndroid
本题的考点是会不会对luajava加密的lua文件进行解密。
解密的关键是分析加密函数，本题的加密落在常规的luaL_loadbufferx函数（参其它对luajava分析的文章）
针对本题的加密写了一个py脚本进行lua解密：
https://github.com/Airrcat/luajava_decode
解密出来得到的是luac，可以使用unluac等软件或一些在线反编译软件进行解密，本题用https://luadec.metaworm.site/这个网站解密效果较好。
exp:
from ctypes import *
cipher = [863918170,
366827450,
2944604520,
1314064158,
2534040034,
1250268803,
3402278143,
1361039932,
3087907484,
3107271874]
key = [
5976,
40857,
3298229483,
1500946329
]
def decrypt(v, key):
v0, v1 = c_uint32(v[0] ^ 14), c_uint32(v[1] ^ 17)
delta = 0x80D6732B
rounds = 38
total = c_uint32(delta * rounds)
for i in range(rounds):
v1.value -= (((v0.value << 4) ^ (v0.value >> 5)) +
v0.value) ^ (total.value + key[(total.value >> 11) & 3])
v0.value -= (((v1.value << 4) ^ (v1.value >> 5)) +
v1.value) ^ (total.value + key[total.value & 3])
total.value -= delta
return v0.value, v1.value
# 标准xtea
if __name__ == "__main__":
value = cipher
print("cypher len:", len(cipher))
flag = b""
for i in range(0, len(value), 2):
res = decrypt(value[i:i+2], key)
flag += res[0].to_bytes(4, 'big') + res[1].to_bytes(4, 'big')
print(flag, len(flag))
"""
Data is : 0x12345678 0x78563412
Encrypted data is : 0xae685ec7 0x59af4238
Decrypted data is : 0x12345678 0x78563412
"""