[CFI-CTF 2018]Automated Reversing

打开全是elf文件

每个文件的格式都是固定的

仅有中间这里有区别

写脚本

for i in range(1, 1009):
    path = r"binaries\binary{}".format(i)
    f = open(path, "rb")
    buf = f.read()
    flag = buf[0xce]
    operate = buf[0xca]
    num = buf[0xcb]
    if operate == 0xf2:
        flag ^= num
    elif operate == 0xea:
        flag += num
    elif operate == 0xc2:
        flag -= num
    print(chr(flag&0xff), end="")

flag{1s_th1s_4_pr0g_ch4ll_0r_4_r3ve3se_ch4ll?}