前置知识
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序列化
会变成这样
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序列化解释
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反序列化
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public,private,protetced
当它是private时
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当他是protetcted
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当我在类之后在创建一个类
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反序列化只可以改变变量,然后不可以自己调用里面的函数,只可以用它给出的函数调用
安全问题
------construct是构造函数
------destruct是析构函数
当我这么调用函数时
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只会输出变量
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当我没有创建新的对象,只将序列化后的字符串进行反序列化,它会调用析 构函数
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test也被触发了,明明没有创建对象
to_string函数
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所以会输出tostring
当我们这么做时
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当我们不创建对象
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输入 编译后的payload,也会自动执行析构函数
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重要
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跟前面一样,它会自动析构,
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我们可以修改url
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改成3,ver,他就会只执行ver
ctf反序列化问题
第一
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第二
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我们得尝试更改isvip中的值改为false,才可以输出flag
我们根据上面的知识3 将halse改成true
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第三
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前面要求要求密码相同,后面要求密码不同
改成这样
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第四关
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出现了多个class,还有eval
这里只可以用destruct这个魔术方法
而destruct这个函数下面的变量是上面new的一个对象
当我们直接将原函数序列化
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所以我么改成backdoor
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然后再改变code
第五关
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出现了过滤意思是匹配o或c后面带有数字的,(i代表大小写)
之前的那个
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o后面就有11,匹配到了无法继续执行
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就如这样
所以我们就得将11改成+11这样就看避免数组直接接触
先将他序列化,然后再编码
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第六关
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前置知识
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用php原生类
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这个原生类是php自带的
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__sleep()
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序列化之前调用 的函数
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它会调用sleep函数
然后不返回password
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__wakeup()
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__tostring()
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echo会把对象当成字符串,所以会触发__tostring()
--invoke()
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---call
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当我们调用一个不存在的函数,这个函数不存在
------callstatic
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__get()
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__set()
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_isset()
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_unset()
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__clone()
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魔术方法总结
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pop链前置知识(tostring和wakeup的使用)
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l
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当我想触发__tostring时,我们得使用上面的source,让source变成一个对象,这样------tostring()刚好能触发,所以我们这么构造
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pop链构造(所以函数的触发)
找小括号,就是当成函数使用的变量
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首先我们想得到flag就得使用involve这个函数,而它又由invoke来调用,所以我们就得想办法触发这个函数,就找下面有没有将变量当函数使用的就发现第22是这样的
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构造推到
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然后这么写
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字符串逃逸(字符串减少)
序列化代码一般以}结束,以;来分隔
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当我们再后面随便写东西,不会影响反序列化
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加成员属性不会报错
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例
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它会将system给去掉,但最终无法反序列化,因为长度不一样
所以我们这么构造
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例题
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字符串增多
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例题
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wakeup()绕过
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引用绕过
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这么构造
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session反序列化
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第一种格式
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第二种格式
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第三种
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漏洞(当seesion序列化和反序列化用不同的方式时会造成这个漏洞)
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在save.php中,存入session并且将其序列化,当我们打开vul.php就会将这个session反序列化,就跟unserialize一样,自动执行,而默认的就会从|开始读
、
phar反序列化漏洞
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一般改这个
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例题
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这里没有反序列化,但我们看到了file_exists这个函数
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返回true说明有这个文件,就可以触发漏洞
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就可以调用这个为协议
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改成jpg也可以,都可以当初phar执行、
------------------图片取自b站橙子科技工作室,小迪