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[原创]第八题 惊天阴谋 by k1ee
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发表于: 2020-12-7 20:46
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去花，修复各种干扰后，取得程序逻辑如下
注册码分为两部分
魔改的AES，动调取得sbox，手算rsbox，解密。
每一位+0x7F得到第二位
调用API进行解密即可
六种运算的虚拟机，把所有指令打出来，然后分析可以看出有很多重复的部分，懒得写程序提炼，于是手动提炼了一部分，12万行缩小到1.2万行，编译爆破程序求解，16线程106分钟解得所有逆向关系
一个可逆算法，直接算出输入
最令人头痛的算法，我记录了所有和输入有关的运算，发现还是可逆的，也就三处需要记录
每一处输入输出关系也就65423个，因此爆破即可，从后往前还原数据
似乎是个矩阵，不过当时太累了，爆破也不是很难
此题应该多解，我没求出预期解
https://docs.microsoft.com/en-us/windows/win32/debug/pe-format
实际上是从KernelBase和advapi32里找函数
const char* username = "141E8F96636898EF";
const char* serial = "dd8c5dd5bff047cb86c51fc808254c0950ebd2d9c7e6b34679a6cda7f96ea0f46d105248c68b6534546d34c26534546d34c26534542538d289a28b2d14d06534546614d225146289a28b6614d249a7096d10522538d22538d289a28b48a21b2d14d041a69b2d14d06614d289a28b25146250a28948a21b48c68b48c68b49829948a21b6d105249a7092c345289a28b6534542c34522d14d050a2896d105225146289a28b6d105249a7092d14d049a7096d34c26d10522d14d049a70948a21b2d14d048c68b48a21b49a70925146248c68b41a69b08a69948c68b48c68b498299";
uint8_t username_md5[16] = { 0 };
md5((uint8_t*)username, strlen(username), username_md5);
uint8_t username_md5_1[16] = { 0 };
md5(username_md5, 8, username_md5_1);
uint8_t username_md5_2[16] = { 0 };
md5(username_md5 + 8, 8, username_md5_2);
uint8_t serial_hex[224] = { 0 };
char* sp = (char*)serial;
for (int i = 0; i < 224; ++i)
{ sscanf_s(sp, "%2hhx", &serial_hex[i]);
sp += 2;
}uint8_t* serial_1 = serial_hex;
uint8_t* serial_2 = serial_hex + 32;
uint8_t result1_1[32] = { 0 };
uint32_t* pi = (uint32_t*)serial_1;
uint32_t* po = (uint32_t*)result1_1;
for (int i = 0; i < 8; ++i)
{ *po++ = transform1_1(*pi++);
}uint8_t result1_2[32] = { 0 };
memcpy(result1_2, result1_1, 32);
HCRYPTPROV ctx;CryptAcquireContextA(&ctx, 0, 0, 24, 0xF0000000);
HCRYPTHASH hash;
CryptCreateHash(ctx, 0x800C, 0, 0, &hash);
unsigned char hashData[20] = { 0x31, 0x5F, 0x4C, 0x30, 0x56, 0x33, 0x5F, 0x42, 0x58, 0x53, 0x5F, 0x46, 0x30, 0x52, 0x45, 0x56, 0x45, 0x52, 0x21, 0x00 };
CryptHashData(hash, hashData, 19, 0);
HCRYPTKEY key;CryptDeriveKey(ctx, 0x6610, hash, 0, &key);
DWORD len = 32;
CryptEncrypt(key, 0, 0, 0, result1_2, &len, 32);
uint8_t result1_2_trans[16] = { 0 };
for (int i = 0; i < 16; ++i)
{ result1_2_trans[i] = result1_2[2 * i];
}transform1_2(result1_2_trans);//Equals MD5 Part1
uint8_t result2_1[32] = { 0 };
transform2_1(serial_2, result2_1);uint8_t result2_2[16] = { 0 };
transform2_2(result2_1, result2_2);transform2_3(result2_2, username_md5_2);const char* username = "141E8F96636898EF";
const char* serial = "dd8c5dd5bff047cb86c51fc808254c0950ebd2d9c7e6b34679a6cda7f96ea0f46d105248c68b6534546d34c26534546d34c26534542538d289a28b2d14d06534546614d225146289a28b6614d249a7096d10522538d22538d289a28b48a21b2d14d041a69b2d14d06614d289a28b25146250a28948a21b48c68b48c68b49829948a21b6d105249a7092c345289a28b6534542c34522d14d050a2896d105225146289a28b6d105249a7092d14d049a7096d34c26d10522d14d049a70948a21b2d14d048c68b48a21b49a70925146248c68b41a69b08a69948c68b48c68b498299";
uint8_t username_md5[16] = { 0 };
md5((uint8_t*)username, strlen(username), username_md5);
uint8_t username_md5_1[16] = { 0 };
md5(username_md5, 8, username_md5_1);
uint8_t username_md5_2[16] = { 0 };
md5(username_md5 + 8, 8, username_md5_2);
uint8_t serial_hex[224] = { 0 };
char* sp = (char*)serial;
for (int i = 0; i < 224; ++i)
{ sscanf_s(sp, "%2hhx", &serial_hex[i]);
sp += 2;
}uint8_t* serial_1 = serial_hex;
uint8_t* serial_2 = serial_hex + 32;
uint8_t result1_1[32] = { 0 };
uint32_t* pi = (uint32_t*)serial_1;
uint32_t* po = (uint32_t*)result1_1;
for (int i = 0; i < 8; ++i)
{ *po++ = transform1_1(*pi++);
}uint8_t result1_2[32] = { 0 };
memcpy(result1_2, result1_1, 32);
HCRYPTPROV ctx;CryptAcquireContextA(&ctx, 0, 0, 24, 0xF0000000);
HCRYPTHASH hash;
CryptCreateHash(ctx, 0x800C, 0, 0, &hash);
unsigned char hashData[20] = { 0x31, 0x5F, 0x4C, 0x30, 0x56, 0x33, 0x5F, 0x42, 0x58, 0x53, 0x5F, 0x46, 0x30, 0x52, 0x45, 0x56, 0x45, 0x52, 0x21, 0x00 };
CryptHashData(hash, hashData, 19, 0);
HCRYPTKEY key;CryptDeriveKey(ctx, 0x6610, hash, 0, &key);
DWORD len = 32;
CryptEncrypt(key, 0, 0, 0, result1_2, &len, 32);
uint8_t result1_2_trans[16] = { 0 };
for (int i = 0; i < 16; ++i)
{ result1_2_trans[i] = result1_2[2 * i];
}transform1_2(result1_2_trans);//Equals MD5 Part1
uint8_t result2_1[32] = { 0 };
transform2_1(serial_2, result2_1);uint8_t result2_2[16] = { 0 };
transform2_2(result2_1, result2_2);transform2_3(result2_2, username_md5_2);AES_ctx actx;int akey[8] = { 0 };
akey[0] = 0x59206F57;
akey[1] = 0x59676E6F;
akey[2] = 0x206E6175;
akey[3] = 0x75486958;
akey[4] = 0x4B206E61;
akey[5] = 0x75586E61;
akey[6] = 0x754C206E;
akey[7] = 0x6E61546E;
AES_init_ctx(&actx, (uint8_t*)akey);
AES_ECB_decrypt(&actx, username_md5_1);AES_ctx actx;int akey[8] = { 0 };
akey[0] = 0x59206F57;
akey[1] = 0x59676E6F;
akey[2] = 0x206E6175;
akey[3] = 0x75486958;
akey[4] = 0x4B206E61;
akey[5] = 0x75586E61;
akey[6] = 0x754C206E;
akey[7] = 0x6E61546E;
AES_init_ctx(&actx, (uint8_t*)akey);
AES_ECB_decrypt(&actx, username_md5_1);uint8_t part1_1[32] = { 0 };
for (int i = 0; i < 16; ++i)
{ part1_1[i * 2] = username_md5_1[i];
part1_1[i * 2 + 1] = username_md5_1[i] + 0x7F;
}uint8_t part1_1[32] = { 0 };
for (int i = 0; i < 16; ++i)
{ part1_1[i * 2] = username_md5_1[i];
part1_1[i * 2 + 1] = username_md5_1[i] + 0x7F;
}HCRYPTPROV ctx;CryptAcquireContextA(&ctx, 0, 0, 24, 0xF0000000);
HCRYPTHASH hash;
CryptCreateHash(ctx, 0x800C, 0, 0, &hash);
unsigned char hashData[20] = { 0x31, 0x5F, 0x4C, 0x30, 0x56, 0x33, 0x5F, 0x42, 0x58, 0x53, 0x5F, 0x46, 0x30, 0x52, 0x45, 0x56, 0x45, 0x52, 0x21, 0x00 };
CryptHashData(hash, hashData, 19, 0);
HCRYPTKEY key;CryptDeriveKey(ctx, 0x6610, hash, 0, &key);
DWORD len = 32;
CryptDecrypt(key, 0, 0, 0, part1_1, &len);
HCRYPTPROV ctx;CryptAcquireContextA(&ctx, 0, 0, 24, 0xF0000000);
HCRYPTHASH hash;
CryptCreateHash(ctx, 0x800C, 0, 0, &hash);
unsigned char hashData[20] = { 0x31, 0x5F, 0x4C, 0x30, 0x56, 0x33, 0x5F, 0x42, 0x58, 0x53, 0x5F, 0x46, 0x30, 0x52, 0x45, 0x56, 0x45, 0x52, 0x21, 0x00 };
CryptHashData(hash, hashData, 19, 0);
HCRYPTKEY key;CryptDeriveKey(ctx, 0x6610, hash, 0, &key);
DWORD len = 32;
CryptDecrypt(key, 0, 0, 0, part1_1, &len);
uint32_t* ansbuf = new uint32_t[0x10000000];
for (int i = 0; i < 16; ++i)
{ uint32_t val = i * 0x10000000;
char filename[128] = { 0 };
sprintf_s(filename, "E:/Ctf/KCTF2020Q4/KCTF-KeyME/Solver/Solver/Release/%08X_%08X.bin", val, val + 0xFFFFFFF);
FILE* fp;
fopen_s(&fp, filename, "rb");
int ret = fread(ansbuf, 4, 0x10000000, fp);
fclose(fp);
for (int k = 0; k < 0x10000000; ++k)
{
uint32_t input = val++;
uint32_t output = ansbuf[k];
for (int t = 0; t < 8; ++t)
{
if (pi[t] == output)
{
po[t] = input;
//pos[t].push_back(input);
}
}
}
}delete[] ansbuf;printf("Serial Part 1\n");
for (int i = 0; i < 32; ++i)
{ printf("%02x", part1_2[i]);
}uint32_t* ansbuf = new uint32_t[0x10000000];
for (int i = 0; i < 16; ++i)
{ uint32_t val = i * 0x10000000;
char filename[128] = { 0 };
sprintf_s(filename, "E:/Ctf/KCTF2020Q4/KCTF-KeyME/Solver/Solver/Release/%08X_%08X.bin", val, val + 0xFFFFFFF);
FILE* fp;
fopen_s(&fp, filename, "rb");
int ret = fread(ansbuf, 4, 0x10000000, fp);
fclose(fp);
for (int k = 0; k < 0x10000000; ++k)
{
uint32_t input = val++;
uint32_t output = ansbuf[k];
for (int t = 0; t < 8; ++t)
{
if (pi[t] == output)
{
po[t] = input;
//pos[t].push_back(input);
}
}
}
}delete[] ansbuf;printf("Serial Part 1\n");
for (int i = 0; i < 32; ++i)
{ printf("%02x", part1_2[i]);
}83bde72e2806ce3c8f424e242559a66314bb37008d62a69bfd1a960f8e4102c883bde72e2806ce3c8f424e242559a66314bb37008d62a69bfd1a960f8e4102c8int buf1[8] = { 0x18111C1A, 0x1190C08, 0x10070B20, 0x151D0217, 0x12161B14, 0xA1E05, 0xD130309, 0x1F0E0604 };
int buf2[8] = { 0x14161715, 0x12040C13, 0xE100603, 0xF1C180A, 0x50B001F, 0x200D1A08, 0x9111D1E, 0x1B010219 };
int buf3[8] = { 0x11ECEE03, 0xC050E14, 0x5F7ED03, 0xE700F600, 0xBEFE800, 0xFF0403F5, 0xF4061600, 0xF90918EF };
uint8_t* p1 = (uint8_t*)buf1;
uint8_t* p2 = (uint8_t*)buf2;
uint8_t* p3 = (uint8_t*)buf3;
uint8_t target_m[16] = { 0x15, 0x09, 0x0c, 0x1f, 0x1c, 0x13, 0x16, 0x19, 0x1d, 0x03, 0x10, 0x0f, 0x01, 0x02, 0x1e, 0x06 };
for (int i = 0; i < 16; ++i)
{ uint8_t mid = target_m[i] - p3[i] + md5c[i];
cal[i] = __ROL__(mid, p1[i] & 7) ^ p2[i];
}int buf1[8] = { 0x18111C1A, 0x1190C08, 0x10070B20, 0x151D0217, 0x12161B14, 0xA1E05, 0xD130309, 0x1F0E0604 };
int buf2[8] = { 0x14161715, 0x12040C13, 0xE100603, 0xF1C180A, 0x50B001F, 0x200D1A08, 0x9111D1E, 0x1B010219 };
int buf3[8] = { 0x11ECEE03, 0xC050E14, 0x5F7ED03, 0xE700F600, 0xBEFE800, 0xFF0403F5, 0xF4061600, 0xF90918EF };
uint8_t* p1 = (uint8_t*)buf1;
uint8_t* p2 = (uint8_t*)buf2;
uint8_t* p3 = (uint8_t*)buf3;
uint8_t target_m[16] = { 0x15, 0x09, 0x0c, 0x1f, 0x1c, 0x13, 0x16, 0x19, 0x1d, 0x03, 0x10, 0x0f, 0x01, 0x02, 0x1e, 0x06 };
for (int i = 0; i < 16; ++i)
{ uint8_t mid = target_m[i] - p3[i] + md5c[i];
cal[i] = __ROL__(mid, p1[i] & 7) ^ p2[i];
}uint16_t r2_r1(uint64_t res, uint64_t v3, uint64_t v2){ std::vector<int> ret;
for (int i = 65422; i >= 0; --i)
{
if (res == (i * (v3 * v3 % 65423 * v2 % 65423) % 65423))
{
ret.push_back(i);
}
}
if (ret.size() != 1)
{
_CrtDbgBreak();
}
return ret[0];
}uint16_t r2_r2(uint64_t res, uint64_t val, uint64_t bp){ std::vector<int> ret;
for (int i = 65422; i >= 0; --i)
{
uint64_t r = ((int64_t)(i - val * bp) % 65423 + 65423) % 65423;
if (res == r)
{
ret.push_back(i);
}
}
if (ret.size() != 1)
{
_CrtDbgBreak();
}
return ret[0];
}uint16_t r2_r3(uint64_t res, uint64_t v1, uint64_t v2, uint64_t v3){ std::vector<int> ret;
for (int i = 65422; i >= 0; --i)
{
uint64_t r = ((int64_t)(i * v1 - v2 * v3) % 65423 + 65423) % 65423;
if (res == r)
{
ret.push_back(i);
}
}
if (ret.size() != 1)
{
_CrtDbgBreak();
}
return ret[0];
}struct re2_op{ int bufptr_res;
int bufptr_another;
uint64_t mul_val1;
uint64_t min_val3;
};void reverse2_2(uint16_t* input, uint8_t* output)
{ uint8_t buf1[0x370 * 16] = { 0 };
int64_t* b1ptr1 = (int64_t*)buf1;
int32_t* t1ptr = (int32_t*)table_trans2;
for (int i = 0; i < 16; ++i)
{
int64_t val1 = *t1ptr++;
for (int k = 15; k >= 0; --k)
{
int64_t val2 = 0;
if (k > 0)
{
int64_t val3 = transform2_calc1(val1, k >> 1);
val2 = val3 * val3 % 65423;
if (k & 1)
val2 = val2 * val1 % 65423;
}
else
{
val2 = 1;
}
*b1ptr1++ = val2;
}
b1ptr1 = (int64_t*)(buf1 + 0x370 * (i + 1));
}
for (int i = 0; i < 16; ++i)
{
uint64_t* b1ptr2 = (uint64_t*)(buf1 + 0x80 + i * 0x370);
*b1ptr2 = 0xDEAD;
}
std::vector<re2_op> ops;
uint64_t* b1ptr3 = (uint64_t*)buf1;
for (int i = 1; i <= 15; ++i)
{
uint64_t* b1ptr7 = (uint64_t*)(buf1 + 0x370 * i + 8 * (i - 1));
for (int a1 = 16 - i; a1 >= 1; --a1)
{
uint64_t val3 = *b1ptr7;
uint64_t* b1ptr8 = b1ptr3;
uint64_t* b1ptr9 = b1ptr7;
for (int a2 = 18 - i; a2 >= 1; --a2)
{
uintptr_t diff3 = ((uintptr_t)b1ptr3 - (uintptr_t)buf1);
uintptr_t diff7 = ((uintptr_t)b1ptr7 - (uintptr_t)buf1);
uintptr_t diff8 = ((uintptr_t)b1ptr8 - (uintptr_t)buf1);
uintptr_t diff9 = ((uintptr_t)b1ptr9 - (uintptr_t)buf1);
if (diff9 % 0x370 == 0x80)
{
re2_op op;
op.bufptr_res = diff9 / 0x370;
op.bufptr_another = diff8 / 0x370;
op.mul_val1 = *b1ptr3;
op.min_val3 = val3;
ops.push_back(op);
}
*b1ptr9++ = ((int64_t)(*b1ptr9 * *b1ptr3 - val3 * *b1ptr8++) % 65423 + 65423) % 65423;
}
b1ptr7 += 110;
}
b1ptr3 += 111;
}
uint16_t* op = (uint16_t*)output;
uint64_t bufrec_1[16] = { 0 };
int64_t* b1p2 = (int64_t*)buf1;
for (int k = 0; k < 16; ++k)
{
int64_t v2 = *b1p2;
int64_t v3 = transform2_calc1(*b1p2, 0x7FC6);
uint16_t ret = r2_r1(input[k], v3, v2);
for (int t = 15; t > k; --t)
{
ret = r2_r2(ret, input[t], *(uint64_t*)(buf1 + k * 0x370 + t * 8));
}
bufrec_1[k] = ret;
b1p2 += 111;
}
for (int i = ops.size() - 1; i >= 0; --i)
{
re2_op op = ops[i];
bufrec_1[op.bufptr_res] = r2_r3(bufrec_1[op.bufptr_res], op.mul_val1, op.min_val3, bufrec_1[op.bufptr_another]);
}
for (int i = 0; i < 16; ++i)
{
op[i] = bufrec_1[i];
}
}uint16_t r2_r1(uint64_t res, uint64_t v3, uint64_t v2){ std::vector<int> ret;
for (int i = 65422; i >= 0; --i)
{
if (res == (i * (v3 * v3 % 65423 * v2 % 65423) % 65423))
{
ret.push_back(i);
}
}
if (ret.size() != 1)
{
_CrtDbgBreak();
}
return ret[0];
}uint16_t r2_r2(uint64_t res, uint64_t val, uint64_t bp){ std::vector<int> ret;
for (int i = 65422; i >= 0; --i)
{
uint64_t r = ((int64_t)(i - val * bp) % 65423 + 65423) % 65423;
if (res == r)
{
ret.push_back(i);
}
}
if (ret.size() != 1)
{
_CrtDbgBreak();
}
return ret[0];
}uint16_t r2_r3(uint64_t res, uint64_t v1, uint64_t v2, uint64_t v3){ std::vector<int> ret;
for (int i = 65422; i >= 0; --i)
{
uint64_t r = ((int64_t)(i * v1 - v2 * v3) % 65423 + 65423) % 65423;
if (res == r)
{
ret.push_back(i);
}
}
if (ret.size() != 1)
{
_CrtDbgBreak();
}
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