SWPUCTF 2021 新生赛-老鼠走迷宫
2023-11-21 17:31:49 Author: mp.weixin.qq.com(查看原文) 阅读量:7 收藏

附件下载
https://wwvc.lanzouj.com/iYLez1br84jg
◆用pyinstxtrator解析exe。
◆重点:将无后缀的5先修改后缀为pyc,然后随便找一个pyc文件补齐5.pyc的前16位十六进制数值(这道题以struct.pyc为例)。
◆将.pyc反编译为.py。
◆找到maze,从而找到最短路径。
下载附件,拿到一个无后缀的文件,丢入winhex里看看,发现是MZ开头的,去搜MZ开头是什么文件。



MZ开头的是.EXE可执行文件。


修改后缀:

64位,无壳,但是该exe是被pyinstaller打包后得到的,我们需要将exe转换为py形式。

pyinstxtractor.py自行下载,在这个页面打开cmd。



使用pyinstxtractor.py反编译exe文件,命令如下:

python pyinstxtractor.py 可执行文件exe的地址



在当前文件夹会多出一个文件夹。

可以看到可疑的文件5,struct。


这里我们需要先将文件5和struct加上后缀.pyc,因为后续需要进行.pyc反编译成.py文件(其实struct可要可不要,struct的作用就是给5.pyc补齐前面缺失的十六进制数值,将其他的正常的.pyc文件替换struct.pyc也可以,因为我发现.pyc文件的前16位数值都是一样的)。



在winhex打开两个pyc文件,将struct的前16位十六进制数复制到5.pyc开头。




记得保存。


将5.pyc文件反编译成.py文件,网址:https://tool.lu/pyc/


down下来,得到一个python文件。
#!/usr/bin/env python
# visit https://tool.lu/pyc/ for more information
# Version: Python 3.7

import random
import msvcrt
(row, col) = (12, 12)
(i, j) = (0, 0)
maze = [
[
1,
0,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1],
(……省略,参考源文章)

print('Mice walk in a maze: wasd to move,q to quit')
print("flag is the shortest path's md5,example:if the shortest path is wasdsdw,the flag is md5('wasdsdw')")
(i, j) = (0, 1)
n = 0
while i == row * 2 and j == col * 2 - 1:
print('ohhhh!!!!you did it')
break
print('your position:({},{})'.format(i, j))
inp = msvcrt.getch()
n += 1
ti = i
tj = j
if b'a' == inp and i > 0:
tj -= 1
elif b'w' == inp and j > 0:
ti -= 1
elif b's' == inp and j < row * 2:
ti += 1
elif b'd' == inp and i < col * 2:
tj += 1
elif b'q' == inp:
exit('bye!!')
else:
print('What???')
if maze[ti][tj] == 1:
print(random.choice([
'no wayy!!',
"it's wall",
'nop']))
continue
elif maze[ti][tj] == 0:
print(random.choice([
'nice!!',
'yeah!!',
'Go on']))
i = ti
j = tj
return None
在maze下面添加一个for循环,输出maze,会报错,把最下面的return none直接删了,这不是重点不要紧。

修改之后的代码,可以直接输出maze。
#!/usr/bin/env python
# visit https://tool.lu/pyc/ for more information
# Version: Python 3.7

import random
import msvcrt
(row, col) = (12, 12)
(i, j) = (0, 0)
maze = [
[
1,
0,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1,
1],
(……省略,参考源文章)

for row in maze:
print(row)
print('Mice walk in a maze: wasd to move,q to quit')
print("flag is the shortest path's md5,example:if the shortest path is wasdsdw,the flag is md5('wasdsdw')")
(i, j) = (0, 1)
n = 0
while i == row * 2 and j == col * 2 - 1:
print('ohhhh!!!!you did it')
break
print('your position:({},{})'.format(i, j))
inp = msvcrt.getch()
n += 1
ti = i
tj = j
if b'a' == inp and i > 0:
tj -= 1
elif b'w' == inp and j > 0:
ti -= 1
elif b's' == inp and j < row * 2:
ti += 1
elif b'd' == inp and i < col * 2:
tj += 1
elif b'q' == inp:
exit('bye!!')
else:
print('What???')
if maze[ti][tj] == 1:
print(random.choice([
'no wayy!!',
"it's wall",
'nop']))
continue
elif maze[ti][tj] == 0:
print(random.choice([
'nice!!',
'yeah!!',
'Go on']))
i = ti
j = tj
[1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
[1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1]
[1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1]
[1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1]
[1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1]
[1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1]
[1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1]
[1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1]
[1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1]
[1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1]
[1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1]
[1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1]
[1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1]
[1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1]
[1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1]
[1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1]
[1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1]
[1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1]
[1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1]
[1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1]
[1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1]
[1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1]
[1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1]
[1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1]
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1]
Mice walk in a maze: wasd to move,q to quit
flag is the shortest path's md5,example:if the shortest path is wasdsdw,the flag is md5('wasdsdw')
Process finished with exit code 0
接下来可以自己慢慢找,也可以写脚本,我直接从(https://blog.csdn.net/qq_42880719/article/details/120581571)那拉的脚本,可以直接输出迷宫的最小路径。
dirs = [(0, 1), (1, 0), (0, -1), (-1, 0)] # 当前位置四个方向的偏移量
path = [] # 存找到的路径

def mark(maze, pos): # 给迷宫maze的位置pos标"2"表示“倒过了”
maze[pos[0]][pos[1]] = 2

def passable(maze, pos): # 检查迷宫maze的位置pos是否可通行
return maze[pos[0]][pos[1]] == 0

def find_path(maze, pos, end):
mark(maze, pos)
if pos == end:
print(pos, end=" ") # 已到达出口,输出这个位置。成功结束
path.append(pos)
return True
for i in range(4): # 否则按四个方向顺序检查
nextp = pos[0] + dirs[i][0], pos[1] + dirs[i][1]
# 考虑下一个可能方向
if passable(maze, nextp): # 不可行的相邻位置不管
if find_path(maze, nextp, end): # 如果从nextp可达出口,输出这个位置,成功结束
print(pos, end=" ")
path.append(pos)
return True
return False

def see_path(maze, path): # 使寻找到的路径可视化
for i, p in enumerate(path):
if i == 0:
maze[p[0]][p[1]] = "E"
elif i == len(path) - 1:
maze[p[0]][p[1]] = "S"
else:
maze[p[0]][p[1]] = 3
print("\n")
for r in maze:
for c in r:
if c == 3:
print('\033[0;31m' + "*" + " " + '\033[0m', end="")
elif c == "S" or c == "E":
print('\033[0;34m' + c + " " + '\033[0m', end="")
elif c == 2:
print('\033[0;32m' + "#" + " " + '\033[0m', end="")
elif c == 1:
print('\033[0;;40m' + " " * 2 + '\033[0m', end="")
else:
print(" " * 2, end="")
print()

if __name__ == '__main__':
maze = [
[1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1],
[1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1],
[1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1],
[1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1],
[1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1],
[1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1],
[1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1],
[1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1],
[1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1],
[1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1],
[1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1],
[1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1],
[1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1],
[1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1],
[1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1],
[1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1],
[1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1],
[1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1],
[1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1],
[1, 0, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1],
[1, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1],
[1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1]]

start = (0, 1)
end = (24, 23)
find_path(maze, start, end)
see_path(maze, path)

迷宫最短路径。



使用wasd表示最短路径就是(一定不要忘了最后一个 * 还需要往下走一个才到达终点,我服,看了半天才找到这个错误):
sssssddssddssaaaassssddwwddddssssssaawwaassssddssaassddddwwddssddwwwwwwwwaawwddwwwwaaaawwddwwwwddssssddwwwwddddwwddddssaassaassddddssddssaassssssddsssssss
根据python里面的内容,flag是用wasd表示的最短路径的md5值。



取32位小写,69193150b15c87d39252d974bc323217。


flag:NSSCTF{69193150b15c87d39252d974bc323217}

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