BUUCTF pyre

拿到的文件是一个后缀是.pyc的文件，有点迷糊，百度了一下发现可以用网上的python反编译在线工具反编译，反编译之后得到代码：

#!/usr/bin/env python
# visit http://tool.lu/pyc/ for more information
print "Welcome to Re World!"
print "Your input1 is your flag~"
l = len(input1)
for i in range(l):num = ((input1[i] + i) % 128 + 128) % 128code += num
for i in range(l - 1):code[i] = code[i] ^ code[i + 1]
print code
code = ["\x1f","\x12","\x1d","(","0","4","\x01","\x06","\x14","4",",","\x1b","U","?","o","6","*",":","\x01","D",";","%","\x13",
]

分析了下代码，大概猜测就是自己输入一个flag，然后经过两次变换得到另一个flag
代码比较简单，直接上脚本：


code = ["\x1f","\x12","\x1d","(","0","4","\x01","\x06","\x14","4",",","\x1b","U","?","o","6","*",":","\x01","D",";","%","\x13",]l = len(code)for i in range(l-2,-1,-1):code[i]=chr(ord(code[i])^ord(code[i+1]))for i in range(len(code)):print(chr((ord(code[i])-i)%128),end='')

运行得到flag：

总结：
1.《.pyc》的python文件可以用网页python反编译在线工具反编译
2.因为（a+b）%c=（a%c+b%c）%c，所以原程序中((input1[i] + i) % 128 + 128) % 128=(input1[i] + i) %128，如下图：

3.a=(b-c)%d的逆运算为b=（a+c）%d

BUUCTF pyre相关推荐

buuctf pyre
buuctf 逆向pyre 最近看到不少py逆向,记录一道题下载原件发现是pyc文件,先利用uncompyle生成py文件(之前用py3.8.6的版本下载死活不行,在老学长的帮助下发现uncompy ...
buuctf——pyre
1得到.pyc文件. 反编译pyc文件,首先要下载uncompyle (打开cmd 输入命令:pip install uncompyle) 在cmd窗口输入命令:uncompyle6 文件名.pyc& ...
BUUCTF Reverse/[GWCTF 2019]pyre
BUUCTF Reverse/[GWCTF 2019]pyre 下载得到一个pyc文件,用这个在线反编译pyc,pyo反汇编出代码 print 'Welcome to Re World!' print ...
[BUUCTF]REVERSE——[GWCTF 2019]pyre
[GWCTF 2019]pyre 附件步骤: 1.附件是pyc文件,用python打不开,百度后得知用python反编译工具打开,分享一个python反编译在线网站反编译后是这段代码 #!/usr ...
buuctf GWCTF2019 pyre
(36条消息) GWCTF 2019 pyre YuSec_顾殇の点的博客-CSDN博客https://blog.csdn.net/weixin_43859686/article/details/10 ...
buuctf/re/近日总结/rome,pyre等（详细解释）
rome: 检测到无壳,32位直接用IDA打开,转到main函数 int func() {int result; // eaxint v1[4]; // [esp+14h] [ebp-44h]uns ...
BUUCTF 逆向工程(reverse)之[GWCTF 2019]pyre
下载好题目后,发现后缀名为:.pyc 所以使用python这些反编译工具:https://tool.lu/pyc/ 利用这个网站反编译一下就可以得到Python的源代码 #!/usr/bin/env ...
buuctf GWCTF 2019 pyre
下载题目发现是一个pyc文件,关于pyc的详细解释,我看到了这篇文章(6条消息) .pyc是什么?_loveliuzz的博客-CSDN博客_.pyc pyc文件是PyCodeObject的一种持久化保 ...
BUUCTF Reverse pyre
这道题算是比较简单的逆算法了,初入逆向,想借这个题来理理自己的思路拿到附件,发现是一个.pyc文件,这里简单介绍一下详细介绍可以参考大佬博客:什么是pyc文件,把python的py文件编译成pyc ...

BUUCTF pyre

BUUCTF pyre

BUUCTF pyre相关推荐

最新文章

热门文章