BCTF“百度杯”全国网络安全技术对抗赛,是由百度公司主办,清华和北大的安全技术专家提供技术支持,紫金江宁、南京赛宁承办,面向全国范围网络安全技术实战竞赛!
BCTF 周五突然看到了，之前也看了一下，以前从来没参加过，比较感兴趣，遂注册战队加入。
本人小菜，其实也就是想看看，周六看到有人推荐《天注定》于是看了一下，看完回不过神，于是顺手拿了一本书，《蛙》，真的不错，自从毕业就很少看书，居然一直看到7点。
BCTF的事，好像忘，看了最强大脑，正准备睡觉，看到群里有人说了一下BCTF，于是欣欣然打开，没想到这么虐心啊……
MISC 初来乍到
看到题目完全没有思路，直接F12看了，没有任何信息，然后一看90%的战队都做了，然后一遍一遍的看题目，我X，不是真的就@的一下就行了吧，于是打开微博，@了，顺便Follow了，本来没注意，就是试一下，等了一会儿，看到微博有提示，新的朋友，下面公司一栏就是flag……我只想说，ca0……不知道其它战友是什么心情……
PPC & CRYPTO 混沌密码锁
一样没有思路，这题文字里其实没有什么关系，看了链接，down下来源码，看了两遍，不就是排列组合嘛，虽然，可以从answer的格式来判断大概是什么排列，但是才9个function,fun6,fun2已经用了，那就搞个循环，跑一遍应该非常快，事实上确实很快……
import base64,binascii,zlib
import os,random
base = [str(x) for x in range(10)] + [ chr(x) for x in range(ord('A'),ord('A')+6)]
def abc(str):
return sha.new(str).hexdigest()
def bin2dec(string_num):
return str(int(string_num, 2))
def hex2dec(string_num):
return str(int(string_num.upper(), 16))
def dec2bin(string_num):
num = int(string_num)
mid = []
while True:
if num == 0: break
num,rem = divmod(num, 2)
mid.append(base[rem])
return ''.join([str(x) for x in mid[::-1]])
def dec2hex(string_num):
num = int(string_num)
mid = []
while True:
if num == 0: break
num,rem = divmod(num, 16)
mid.append(base[rem])
return ''.join([str(x) for x in mid[::-1]])
def hex2bin(string_num):
return dec2bin(hex2dec(string_num.upper()))
def bin2hex(string_num):
return dec2hex(bin2dec(string_num))
def reverse(string):
return string[::-1]
def read_key():
os.system('cat flag')
def gb2312(string):
return string.decode('gb2312')
answer='78864179732635837913920409948348078659913609452869425042153399132863903834522365250250429645163517228356622776978637910679538418927909881502654275707069810737850807610916192563069593664094605159740448670132065615956224727012954218390602806577537456281222826375'
func_names = ['fun1', 'fun2', 'fun3', 'fun4', 'fun5', 'fun6', 'fun7', 'fun8', 'fun9']
f={}
f['fun1']=reverse
f['fun2']=base64.b64decode
f['fun3']=zlib.decompress
f['fun4']=dec2hex
f['fun5']=binascii.unhexlify
f['fun6']=gb2312
f['fun7']=bin2dec
f['fun8']=hex2bin
f['fun9']=hex2dec
def check_equal(a, b):
if a == b:
return True
try:
if int(a) == int(b):
return True
except:
return False
return False
def main():
print "Welcome to Secure Passcode System"
print "First, please choose function combination:"
f1 = 'fun3'
f2 = 'fun5'
f3 = 'fun1'
f4 = 'fun4'
"""
for f1 in fun_names:
for f2 in fun_names:
for f3 in fun_names:
for f3 in fun_names: #循环跑出函数组合
"""
if f1 not in func_names or f2 not in func_names or f3 not in func_names or f4 not in func_names:
print 'invalid function combination'
#exit()
#continue
try:
answer_hash = f['fun6'](f['fun2'](f[f1](f[f2](f[f3](f[f4](answer))))))
except:
print "Wrong function combination, you bad guy!"
#exit()
#continue
if len(answer_hash) == 0:
print 'You must be doing some little dirty trick! Stop it!'
#exit()
#continue
usercode = answer
try:
user_hash = f['fun6'](f['fun2'](f[f1](f[f2](f[f3](f[f4](usercode))))))
if user_hash == answer_hash:
if check_equal(answer, usercode):
print "This passcode has been locked, please use the new one\n"
#print f1,f2,f3,f4
print answer_hash
read_key()
exit()
else:
print "Welcome back! The door always open for you, your majesty! "
read_key()
exit()
else:
print "Sorry, bad passcode.\n"
except:
print "Sorry, bad passcode. Please try again."
if __name__ == '__main__':
main()
注释掉exit()，添加continue，但是忘了添加下面的跑出结果时的exit(),跑了还在继续啊，果然添加上，跑出来是fun3,fun5,fun1,fun4,但是很显然，结果只能是This passcode has been locked, please use the new one
但是这些，TMD都不是重点，又看了一下，重点就是一个read_key()，一看代码，我那个去……在客户端跑没用……找不到线上提交的地方，还有我真不这两货是干嘛的……218.2.197.242:9991 218.2.197.243:9991
一看时间，夜里2点了，还是睡吧，感冒都还没有好……
转载自：FreebuF.COM
