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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)
