Re-DD-androideasy

Posted 2020-11-22 gaonuoqi

题目地址

https://dn.jarvisoj.com/challengefiles/DDCTF-Easy.apk.64812266499cc050ac23e190e53b87f7

 

用JEB打开

 

 返回值v4是我们要的

构造脚本

p=[-40, -62, 107, 66, -126, 103, -56, 77, 0x7A, -107, -24, -127, 72, -63, -98, 0x40, -24, -5, -49, -26, 0x4F, -70, -26, -81, 120, 25, 0x6F, -100, -23, -9, 0x7A, -35, 66, -50, -116, 3, -72, 102, -45, -85, 0, 0x7E, -34, 62, 83, -34, 0x30, -111, 61, -9, -51, 0x72, 20, 81, -126, -18, 27, -115, -76, -116, -48, -118, -10, -102, -106, 0x71, -104, 98, -109, 74, 0x30, 0x2F, -100, -88, 0x79, 22, -63, -32, -20, -41, -27, -20, -118, 100, -76, 70, -49, -39, -27, -106, -13, -108, 0x73, -87, -1, -22, -53, 21, -100, 0x7C, -95, -40, 62, -69, 29, 56, -53, 85, -48, 25, 37, -78, 11, -110, -24, -120, -82, 6, -94, -101]

q=[-57, -90, 53, -71, -117, 98, 62, 98, 101, -96, 36, 110, 77, -83, -121, 2, -48, 94, -106, -56, -49, -80, -1, 83, 75, 66, -44, 74, 2, -36, -42, -103, 6, -115, -40, 69, -107, 85, -78, -49, 54, 78, -26, 15, 98, -70, 8, -90, 94, -61, -84, 0x40, 0x70, 51, -29, -34, 0x7E, -21, -126, -71, -31, -24, -60, -2, -81, 66, -84, 85, -91, 10, 84, 70, -8, -63, 26, 0x7E, -76, -104, -123, -71, -126, -62, -23, 11, -39, 70, 14, 59, -101, -39, -124, 91, -109, 102, -49, 21, 105, 0, 37, -128, -57, 0x75, 110, -115, -86, 56, 25, -46, -55, 7, -125, 109, 76, 104, -15, 82, -53, 18, -28, -24]

flag=‘‘
v2=[]

for i in range(len(p)):
        v2.append(p[i]^q[i])


v3=v2[0]
v0=0
while v2[v3+v0]!=0:
        v0+=1

v1=0
while(v1<v0):
        flag+=chr(v2[v3+v1])
        v1+=1

print flag