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[原创]网刃杯逆向wp
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发表于: 2021-9-14 15:51
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根据常数搜索到Sm3，然后爆破就行。
本来用unicorn可以秒这道题，但是不知道我多蠢，模拟了一个自己patch过的文件，导致没跑出来，解出这个题之后才发觉，所以写两种方法。
两个地方反调试：
这里也需要过跳转：
关键地方就是check分数，得到正确的分数进行简单计算即可：
要得到score，patch反调试，然后程序内改汇编进行爆破。
.text:00992388 90 nop
.text:00992389
.text:00992389 loc_992389: ; CODE XREF: sub_992290+12C↓j
.text:00992389 8B 8D 68 FF FF FF mov ecx, [ebp+var_98]
.text:0099238F 8B 01 mov eax, [ecx+0]
.text:00992391 83 C0 01 add eax, 1
.text:00992394 89 01 mov [ecx], eax
.text:00992396 89 41 4C mov [ecx+4Ch], eax
.text:00992399 90 nop
.text:0099239A 90 nop
.text:0099239B 90 nop
.text:0099239C 90 nop
拿到分数。
unicorn模拟程序爆破解法：
ss = ['6b8575c6092240cde08414dafd535bee', 'f0f659f2951290ad5e076b3fe5e70425', 'c1d6c663570de9fad13ddef955d8a02b', '14c4e442fba6d820ea90ae73ed90ad83', '25d997669868d0cf89782349256efb33', '78b1ea6bb1ac10287864c8f52d2758b6', '67d1259c26765356ddb58c6faf28080c', 'c1e14e0c86f55ba1d74b35b66f96ad36', '3e4f3ee942d1a57182e24df201b7022b', 'c35557f7e5c389061fb2e2ffa1a644ad', '15593844fae18fe1a25f3a9017c73810', 'c6c21ca591a63755fd77bf5c55a0238a', 'f90cb529875e83cc191c0e10ead6f73e', '3ddbe25f9b183c3e2c33c3b1e501fcd8', '30fdf04c347f1d4e335bda670d54eaaf', '33feb100c8c7c3769af6e9d26486c646']
m = '77'
IV='7380166f4914b2b9172442d7da8a0600a96f30bc163138aae38dee4db0fb0e4e'
#填充函数def filling(m):
#消息m是一个16进制字符串
#直接加16进制比较好
#61626364616263646162636461626364616263646162636461626364616263646162636461626364616263646162636461626364616263646162636461626364
#a = int(m,16)
#b = bin(a)[2:]#消息转换为二进制
length_b = len(m)*4#记录消息的长度
#s1='{:04b}'.format(s1)
b = m
b = b + '8'#补 1
c = len(b)%128
c = 112 - c#补 0 的个数
d = '0'*c
b = b + d#补 0
length_m = '{:016x}'.format(length_b)#也是16进制
b = b + length_m#填充完毕
#b = int(b)
#b = hex(b)[2:]
return b
#分组函数def fenzu(m):
m = filling(m)
len_m = len(m)/128
m_list = []
for i in range(int(len_m)):
a = m[0+128*i:+128*(i+1)]
m_list.append(a)
return m_list
#扩展函数def expand(m,n):#n代表是第几组消息，消息之间没有关系，不用迭代
B = fenzu(m)#列表
W = ['0' for i in range(68)]
W_0 = ['0' for i in range(64)]
for i in range(int(len(B[n])/8)):#128/8=16个字
w = B[n][i*8:(i+1)*8]
W[i] = w
for j in range(16,68):
a = or_16(W[j-16],W[j-9])
W_j_3 = Cyc_shift(W[j-3],15)
#print(W_j_3)
a = or_16(a,W_j_3)
a = Replace_P1(a)
#print(a)
W_j_13=Cyc_shift(W[j-13],7)
a = or_16(a,W_j_13)
a = or_16(a,W[j-6])
W[j]=a
#return W
for j in range(64):
W_0[j]=or_16(W[j],W[j+4])
return W,W_0
#置换函数def Replace_P1(X):
#X为32位字
X_15 = Cyc_shift(X,15) #循环移位
X_23 = Cyc_shift(X,23)
a = or_16(X,X_15)
a = or_16(a,X_23)
return a
#置换函数def Replace_P0(X):
#X为32位字
X_9 = Cyc_shift(X,9)
X_17 = Cyc_shift(X,17)
a = or_16(X,X_9)
a = or_16(a,X_17)
return a
#异或函数def or_16(A,B):
A = int(A,16)
B = int(B,16)
C = A ^ B
C = '{:08x}'.format(C)
return C
#循环移位函数def Cyc_shift(W,n):
a = int(W,16)
a = '{:032b}'.format(a)
while n>=32:
n=n-32
a = a[n:] + a[:n]
a = int(a,2)
a = '{:08x}'.format(a)
return a
#常量Tjdef T_j(j):
if j<=15:
T_j='79cc4519'
else:
T_j='7a879d8a'
return T_j
#mod 2^32 算术加运算def add(x,y):
x = int(x,16)
x = '{:032b}'.format(x)
x = list(x)
y = int(y, 16)
y = '{:032b}'.format(y)
y = list(y)
#print(x)
#print(y)
a = [0 for _ in range(32)]
carry = 0
for i in range(32):
m = int(x[31-i])+int(y[31-i])+carry
if m>=2:
d=m-2
a[31-i]=str(d)
carry=1
else:
carry=0
d=m
a[31 - i] = str(d)
#print(a)
b=''.join(a)
b=int(b,2)
b='{:08x}'.format(b)
return b
#布尔函数def FF_j(X,Y,Z,j):
if j<=15:
a = or_16(X,Y)
a = or_16(a,Z)
else:
a = and_Cal(X,Y)
b = and_Cal(X,Z)
c = and_Cal(Y,Z)
a = or_Cal(a,b)
a = or_Cal(a,c)
return a
#布尔函数def GG_j(X, Y, Z, j):
if j <= 15:
a = or_16(X, Y)
a = or_16(a, Z)
else:
a = and_Cal(X,Y)
b = qufan(X)
b = and_Cal(b,Z)
a = or_Cal(a,b)
return a
#与运算函数def and_Cal(a,b):
a = int(a,16)
b = int(b,16)
a_b = a & b
a_b = '{:08x}'.format(a_b)
return a_b
#或运算函数def or_Cal(a,b):
a = int(a, 16)
b = int(b, 16)
a_b = a | b
a_b = '{:08x}'.format(a_b)
return a_b
#按位取反函数def qufan(A):
A = int(A,16)
A = '{:032b}'.format(A)
A = list(A)
for i in range(32):
if A[i]=='0':
A[i]='1'
else:
A[i]='0'
A = ''.join(A)
A = int(A,2)
A = '{:08x}'.format(A)
return A
#压缩函数m_list = fenzu(m)
m_len = len(m_list)
V = ['0' for i in range(m_len+1)]
V[0]=IV
#压缩函数def CF(m,n,k):
w = expand(m, n)
W = w[0]
W_0 = w[1]
A=V[k][0:8]
B=V[k][8:16]
C=V[k][16:24]
D=V[k][24:32]
E=V[k][32:40]
F=V[k][40:48]
G=V[k][48:56]
H=V[k][56:64]
#print(W_0)
all=''
for j in range(64):
#print(E)
b= a = Cyc_shift(A,12)
#t = b
T = T_j(j)
#
T = Cyc_shift(T,j)#忘记移位了，移位问题
a = add(a,E)
a = add(a,T)
SS1 = Cyc_shift(a,7)
SS2 = or_16(SS1,b)
b = FF_j(A,B,C,j)
b = add(b,D)
b = add(b,SS2)
TT1 = add(b,W_0[j]) #
b = GG_j(E,F,G,j)
b = add(b, H)
b = add(b, SS1)
TT2 = add(b, W[j]) #
D = C
C = Cyc_shift(B,9)
B = A
A = TT1#
H = G
G = Cyc_shift(F,19)
F = E
E = Replace_P0(TT2) #
all = A+B+C+D+E+F+G+H
#print(all)
#V[k+1]=or_16(all,V[k])
#return V[k+1]
#print(t)
#return all
V[k+1]=or_16(V[k],all)
#print(CF(m,0,0))#print(V)def hash(m=m):
for i in range(m_len):
v_n=CF(m,i,i)
#print(V[-1])
return V[-1]
#b=''#b=a[0:8]+'\0'+a[8:16]+'\0'+a[16:24]+'\0'+a[24:32]+'\0'+a[32:40]+'\0'+a[40:48]+'\0'+a[48:56]+'\0'+a[56:64]#print(b)flag = ""
ttt = ""
for j in range(len(ss)):
for i in range(0xff):
arg = ttt + hex(i)[2:].rjust(2,"0")
res = hash(m=arg)[:32]
#print(res, i)
if res == ss[j]:
flag += chr(i)
ttt += hex(i)[2:].rjust(2,"0")
print(flag)
break
#print('输入的消息m是:\n',m)#print('消息m的hash值为:\n',b)ss = ['6b8575c6092240cde08414dafd535bee', 'f0f659f2951290ad5e076b3fe5e70425', 'c1d6c663570de9fad13ddef955d8a02b', '14c4e442fba6d820ea90ae73ed90ad83', '25d997669868d0cf89782349256efb33', '78b1ea6bb1ac10287864c8f52d2758b6', '67d1259c26765356ddb58c6faf28080c', 'c1e14e0c86f55ba1d74b35b66f96ad36', '3e4f3ee942d1a57182e24df201b7022b', 'c35557f7e5c389061fb2e2ffa1a644ad', '15593844fae18fe1a25f3a9017c73810', 'c6c21ca591a63755fd77bf5c55a0238a', 'f90cb529875e83cc191c0e10ead6f73e', '3ddbe25f9b183c3e2c33c3b1e501fcd8', '30fdf04c347f1d4e335bda670d54eaaf', '33feb100c8c7c3769af6e9d26486c646']
m = '77'
IV='7380166f4914b2b9172442d7da8a0600a96f30bc163138aae38dee4db0fb0e4e'
#填充函数def filling(m):
#消息m是一个16进制字符串
#直接加16进制比较好
#61626364616263646162636461626364616263646162636461626364616263646162636461626364616263646162636461626364616263646162636461626364
#a = int(m,16)
#b = bin(a)[2:]#消息转换为二进制
length_b = len(m)*4#记录消息的长度
#s1='{:04b}'.format(s1)
b = m
b = b + '8'#补 1
c = len(b)%128
c = 112 - c#补 0 的个数
d = '0'*c
b = b + d#补 0
length_m = '{:016x}'.format(length_b)#也是16进制
b = b + length_m#填充完毕
#b = int(b)
#b = hex(b)[2:]
return b
#分组函数def fenzu(m):
m = filling(m)
len_m = len(m)/128
m_list = []
for i in range(int(len_m)):
a = m[0+128*i:+128*(i+1)]
m_list.append(a)
return m_list
#扩展函数def expand(m,n):#n代表是第几组消息，消息之间没有关系，不用迭代
B = fenzu(m)#列表
W = ['0' for i in range(68)]
W_0 = ['0' for i in range(64)]
for i in range(int(len(B[n])/8)):#128/8=16个字
w = B[n][i*8:(i+1)*8]
W[i] = w
for j in range(16,68):
a = or_16(W[j-16],W[j-9])
W_j_3 = Cyc_shift(W[j-3],15)
#print(W_j_3)
a = or_16(a,W_j_3)
a = Replace_P1(a)
#print(a)
W_j_13=Cyc_shift(W[j-13],7)
a = or_16(a,W_j_13)
a = or_16(a,W[j-6])
W[j]=a
#return W
for j in range(64):
W_0[j]=or_16(W[j],W[j+4])
return W,W_0
#置换函数def Replace_P1(X):
#X为32位字
X_15 = Cyc_shift(X,15) #循环移位
X_23 = Cyc_shift(X,23)
a = or_16(X,X_15)
a = or_16(a,X_23)
return a
#置换函数def Replace_P0(X):
#X为32位字
X_9 = Cyc_shift(X,9)
X_17 = Cyc_shift(X,17)
a = or_16(X,X_9)
a = or_16(a,X_17)
return a
#异或函数def or_16(A,B):
A = int(A,16)
B = int(B,16)
C = A ^ B
C = '{:08x}'.format(C)
return C
#循环移位函数def Cyc_shift(W,n):
a = int(W,16)
a = '{:032b}'.format(a)
while n>=32:
n=n-32
a = a[n:] + a[:n]
a = int(a,2)
a = '{:08x}'.format(a)
return a
#常量Tjdef T_j(j):
if j<=15:
T_j='79cc4519'
else:
T_j='7a879d8a'
return T_j
#mod 2^32 算术加运算def add(x,y):
x = int(x,16)
x = '{:032b}'.format(x)
x = list(x)
y = int(y, 16)
y = '{:032b}'.format(y)
y = list(y)
#print(x)
#print(y)
a = [0 for _ in range(32)]
carry = 0
for i in range(32):
m = int(x[31-i])+int(y[31-i])+carry
if m>=2:
d=m-2
a[31-i]=str(d)
carry=1
else:
carry=0
d=m
a[31 - i] = str(d)
#print(a)
b=''.join(a)
b=int(b,2)
b='{:08x}'.format(b)
return b
#布尔函数def FF_j(X,Y,Z,j):
if j<=15:
a = or_16(X,Y)
a = or_16(a,Z)
else:
a = and_Cal(X,Y)
b = and_Cal(X,Z)
c = and_Cal(Y,Z)
a = or_Cal(a,b)
a = or_Cal(a,c)
return a
#布尔函数def GG_j(X, Y, Z, j):
if j <= 15:
a = or_16(X, Y)
a = or_16(a, Z)
else:
a = and_Cal(X,Y)
b = qufan(X)
b = and_Cal(b,Z)
a = or_Cal(a,b)
return a
#与运算函数def and_Cal(a,b):
a = int(a,16)
b = int(b,16)
a_b = a & b
a_b = '{:08x}'.format(a_b)
return a_b
#或运算函数def or_Cal(a,b):
a = int(a, 16)
b = int(b, 16)
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