1. 抓包并且hook

1.1 登录请求抓包`charles + 系统代理`就可以抓包

charles + 系统代理就可以抓包

POST /market-activity/register/intention?appid=38741001&did=c69583270de11ab95119c90cff96c59f&noncestr=69fc49&svs=v3&timestamp=1734095423&sign=a9be61f92bdee069d00b34e2415443332211a27fc0604a9d4b2fe3d972af0137 HTTP/1.1
Auth-Token: 
User-Agent: AndroidSDKbuiltforarm64 android 9 7.59.0 2.0
token: 477c33c6-2f38-4363-a670-314393b47c1b
AKC-MODEL: AndroidSDKbuiltforarm64
AKC-OS: android
AKC-OS-VERSION: 9
AKC-APP-VERSION: 7.59.0
AKC-APP-API-VERSION: 2.0
AKC-APP-BUILD-VERSION: 75900
AKC-DID: c69583270de11ab95119c90cff96c59f
AKC-APP-CHANNEL: 2005
applicationId: com.aikucun.akapp
x-auth-token: 
live-channel: 20
dtdToken: 675c3035o69t16VHDZSesSmuU0Saf7ahv6rlEk13
app2H5Token: 
uid: 
subUid: 
APP-LOGIN-CHANNEL: akcApp
app-request-id: 3ed72013807d4df9a7896c6ad9a47e0e
PAGE-NAME: %E7%99%BB%E5%BD%95
TRACKER-SESSION-ID: 2a99dad141359a53
APP-USER-TYPE: 6
Content-Type: application/json; charset=UTF-8
Content-Length: 134
Host: zuul.aikucun.com
Connection: Keep-Alive
Accept-Encoding: gzip

{"smsChecking":false,"channelApp":"akapp","mobile":"13122223333","channel":"2005","deviceId":"358240051111110","channelPattern":"app"}

我们本次主要分析这个sign

1.2 frida检测

附加frida，发现秒退，这个时候我们已经是魔改的fridaGitHub - taisuii/rusda: 对frida 16.2.1的patch并且更换端口了


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(base) r@R aikucun % frida -H 127.0.0.1:12345 -f com.aikucun.akapp
 ____
/ _  |   Frida 16.2.1 - A world-class dynamic instrumentation toolkit
| (_| |
> _  |   Commands:
/_/ |_|       help      -> Displays the help system
. . . .       object?   -> Display information about 'object'
. . . .       exit/quit -> Exit
. . . .
. . . .   More info at https://frida.re/docs/home/
. . . .
. . . .   Connected to 127.0.0.1:12345 (id=socket@127.0.0.1:12345)
Spawned `com.aikucun.akapp`. Resuming main thread!                     
[Remote::com.aikucun.akapp ]-> Process terminated
[Remote::com.aikucun.akapp ]->
 
Thank you for using Frida!
(base) r@R aikucun %

hook 一下dlopen

function hookdlopen() {
    var dlopen = Module.findExportByName(null, "dlopen");
    var android_dlopen_ext = Module.findExportByName(null, "android_dlopen_ext");
    Interceptor.attach(dlopen, {
        onEnter: function (args) {
            var path_ptr = args[0];
            var path = ptr(path_ptr).readCString();
            console.log("[dlopen:]", path);
        },
        onLeave: function (retval) {
        }
    });
    Interceptor.attach(android_dlopen_ext, {
        onEnter: function (args) {
            var path_ptr = args[0];
            var path = ptr(path_ptr).readCString();
            console.log("[dlopen_ext:]", path);
        },
        onLeave: function (retval) {
        }
    });
}

在 libmsaoaidsec.so 处退出，app没有结束，frida被杀掉了

(base) r@R aikucun % frida -H 127.0.0.1:12345 -f com.aikucun.akapp -l hook.js
 ____
/ _  |   Frida 16.2.1 - A world-class dynamic instrumentation toolkit
| (_| |
> _  |   Commands:
/_/ |_|       help      -> Displays the help system
. . . .       object?   -> Display information about 'object'
. . . .       exit/quit -> Exit
. . . .
. . . .   More info at https://frida.re/docs/home/
. . . .
. . . .   Connected to 127.0.0.1:12345 (id=socket@127.0.0.1:12345)
Spawned `com.aikucun.akapp`. Resuming main thread!                     
[Remote::com.aikucun.akapp ]-> [dlopen_ext:] /system/framework/oat/arm64/org.apache.http.legacy.boot.odex
[dlopen_ext:] /data/app/com.aikucun.akapp-Gqd0OXL0bAt7H-zUkRSKuA==/oat/arm64/base.odex
[dlopen_ext:] /data/app/com.aikucun.akapp-Gqd0OXL0bAt7H-zUkRSKuA==/lib/arm64/libc++_shared.so
[dlopen_ext:] /data/app/com.aikucun.akapp-Gqd0OXL0bAt7H-zUkRSKuA==/lib/arm64/libmarsxlog.so
[dlopen_ext:] /data/app/com.aikucun.akapp-Gqd0OXL0bAt7H-zUkRSKuA==/lib/arm64/libmmkv.so
[dlopen_ext:] /data/app/com.aikucun.akapp-Gqd0OXL0bAt7H-zUkRSKuA==/lib/arm64/libmsaoaidsec.so
Process terminated
[Remote::com.aikucun.akapp ]->
 
Thank you for using Frida!
(base) r@R aikucun %

1.3 过检测

这个检测其实就是在加载so的时候，创建了检测线程，具体的话可以分析libmsaoaidsec.so的 .init_proc函数

那么其实已经有很多网友分析过这个了，hook__system_property_get函数寻找hook时机，找到创建线程的地方然后把它替换掉固然是个好方法

不过这里直接粗暴一点，hook pthread_create，只要是在libmsaoaidsec.so里面创建的线程，我们统统替换掉

function replace(addr) {
    Interceptor.replace(addr, new NativeCallback(function () {
        console.log(`replace ${addr}`)
    }, 'void', []));
}
function hook_pthread_create(soname) {
    let replaces = [];  // 用来记录已经替换的函数偏移
    // int pthread_create(pthread_t *thread, const pthread_attr_t *attr, void *(*start_routine)(void*), void *arg);
    let pthread_create = Module.findExportByName("libc.so", "pthread_create");
    if (!pthread_create) {
        console.log("pthread_create not found in libc.so");
        return;
    }
    Interceptor.attach(pthread_create, {
        onEnter: function (args) {
            let start_routine = args[2];
            let libmsaoaidsec = Process.findModuleByAddress(start_routine);
            if (libmsaoaidsec && libmsaoaidsec.name === soname) {
                if (!replaces.includes(start_routine.toString())) {
                    let libmsaoaidsec_addr = libmsaoaidsec.base;
                    let func_offset = start_routine.sub(libmsaoaidsec_addr);
                    console.log("The thread function offset address in libmsaoaidsec.so(" + libmsaoaidsec_addr + ") is " + func_offset);
                    console.log("replace: " + func_offset);
                    replaces.push(start_routine.toString());
                    replace(start_routine)
                }
            }
        }
    });
}

成功过掉检测，一共两处线程创建的地方：0x175f8和0x16d30，

(base) r@R aikucun % frida -H 127.0.0.1:12345 -l hook.js -f com.aikucun.akapp
 ____
/ _  |   Frida 16.2.1 - A world-class dynamic instrumentation toolkit
| (_| |
> _  |   Commands:
/_/ |_|       help      -> Displays the help system
. . . .       object?   -> Display information about 'object'
. . . .       exit/quit -> Exit
. . . .
. . . .   More info at https://frida.re/docs/home/
. . . .
. . . .   Connected to 127.0.0.1:12345 (id=socket@127.0.0.1:12345)
Spawned `com.aikucun.akapp`. Resuming main thread!                     
[Remote::com.aikucun.akapp ]-> replace 0x7b6b55a5f8
replace 0x7b6b559d30
[Remote::com.aikucun.akapp ]->

这个检测在很多app中都是存在的，这个方式在其他app中不一定适用

2. 算法还原

2.1. java层

无套路定位到
在这里插入图片描述

2.2. so层

无套路，可读性非常高，都是字符串拼接

在这里插入图片描述

这个digest函数是调用的java层进行加密的

在这里插入图片描述

2.3 算法还原

获取加密参数以及sha256 的参数，结果一致

function hook() {
    if (Java.available) {
 
        console.log("Java hook start")
        Java.perform(function () {
            let MXSecurity = Java.use("com.mengxiang.arch.security.MXSecurity");
            MXSecurity["signV3"].implementation = function (url, nonceStr, timestamp, body) {
                console.log(`MXSecurity.signV3 is called: url=${url}, nonceStr=${nonceStr}, timestamp=${timestamp}, body=${body}`);
                let result = this["signV3"](url, nonceStr, timestamp, body);
                console.log(`MXSecurity.signV3 result=${result}`);
                return result;
            };
 
            let LoginModel = Java.use("com.aikucun.akapp.business.login.model.LoginModel");
            LoginModel["authCode"].implementation = function (phoneNum, userid, type, rcsTraceId, captchaToken) {
                console.log(`LoginModel.authCode is called: phoneNum=${phoneNum}, userid=${userid}, type=${type}, rcsTraceId=${rcsTraceId}, captchaToken=${captchaToken}`);
                let result = this["authCode"](phoneNum, userid, type, rcsTraceId, captchaToken);
                console.log(`LoginModel.authCode result=${result}`);
                return result;
            };
 
            let MessageDigest = Java.use("java.security.MessageDigest");
            MessageDigest.digest.overload("[B").implementation = function (input) {
                const byteArray = Java.array('byte', input);
                // 将 byte[] 转换为字符串
                let plaintext = '';
                for (let i = 0; i < byteArray.length; i++) {
                    plaintext += String.fromCharCode(byteArray[i] & 0xff);
                }
                if(plaintext.indexOf("38741001") != -1){
                    console.log("[+] MessageDigest.digest(byte[]) called");
                    console.log("Plaintext: " + plaintext);
                }
                // 调用原始方法
                return this.digest(input);
            };
        });
 
    } else {
        console.log("Java.available is false")
    }
}
var hook_num = 0
function replace(addr) {
    Interceptor.replace(addr, new NativeCallback(function () {
        console.log(`replace ${addr}`)
        hook_num = hook_num + 1
        if (hook_num >= 2) {
            hook()
        }
    }, 'void', []));
 
}

(base) r@R aikucun % frida -H 127.0.0.1:12345 -l hook.js -f com.aikucun.akapp
 ____
/ _  |   Frida 16.2.1 - A world-class dynamic instrumentation toolkit
| (_| |
> _  |   Commands:
/_/ |_|       help      -> Displays the help system
. . . .       object?   -> Display information about 'object'
. . . .       exit/quit -> Exit
. . . .
. . . .   More info at https://frida.re/docs/home/
. . . .
. . . .   Connected to 127.0.0.1:12345 (id=socket@127.0.0.1:12345)
Spawned `com.aikucun.akapp`. Resuming main thread!                     
[Remote::com.aikucun.akapp ]-> The thread function offset address in libmsaoaidsec.so(0x7b6b5e4000) is 0x175f8
replace: 0x175f8
The thread function offset address in libmsaoaidsec.so(0x7b6b5e4000) is 0x16d30
replace: 0x16d30
replace 0x7b6b5fb5f8
replace 0x7b6b5fad30
Java hook start
MXSecurity.signV3 is called: url=https://zuul.aikucun.com/akucun-base-data-new/base/address/selectAddrVersion?appid=38741001&did=8e72f37ab5db201b91de47172047e760&noncestr=3d0f39&svs=v3&timestamp=1734184260, nonceStr=3d0f39, timestamp=1734184260, body=
[+] MessageDigest.digest(byte[]) called
Plaintext: appid=38741001&svs=v3&noncestr=3d0f39&timestamp=1734184260&secret=04fdc5e4d9c7420e896ee92b17c68e9f&url=https://zuul.aikucun.com/akucun-base-data-new/base/address/selectAddrVersion?appid=38741001&did=8e72f37ab5db201b91de47172047e760&noncestr=3d0f39&svs=v3&timestamp=1734184260
MXSecurity.signV3 result=5c927464497d321ac3ff49d817cc571d696da21e828ea75bdc9e3465af8a17ae
MXSecurity.signV3 is called: url=https://m.xiangdian.com/api/mshop/mshop-aggr-prod/outer/common/bwl/isHitByBatch?appid=38741001&did=8e72f37ab5db201b91de47172047e760&noncestr=22f096&svs=v3&timestamp=1734184260, nonceStr=22f096, timestamp=1734184260, body=398a40be5a2a6a5a742f35b1b606277a
[+] MessageDigest.digest(byte[]) called
Plaintext: appid=38741001&svs=v3&noncestr=22f096&timestamp=1734184260&secret=04fdc5e4d9c7420e896ee92b17c68e9f&url=https://m.xiangdian.com/api/mshop/mshop-aggr-prod/outer/common/bwl/isHitByBatch?appid=38741001&did=8e72f37ab5db201b91de47172047e760&noncestr=22f096&svs=v3&timestamp=1734184260&398a40be5a2a6a5a742f35b1b606277a
MXSecurity.signV3 result=bd809e352277f9357b436ed424a8fd62b546f415e7f9e7875a05bda5aa5f6704
MXSecurity.signV3 is called: url=https://m.xiangdian.com/api/mshop/mshop-aggr-prod/outer/v1/material/create/createAuth?appid=38741001&did=8e72f37ab5db201b91de47172047e760&noncestr=9908c3&svs=v3&timestamp=1734184261, nonceStr=9908c3, timestamp=1734184261, body=37a6259cc0c1dae299a7866489dff0bd
[+] MessageDigest.digest(byte[]) called
Plaintext: appid=38741001&svs=v3&noncestr=9908c3&timestamp=1734184261&secret=04fdc5e4d9c7420e896ee92b17c68e9f&url=https://m.xiangdian.com/api/mshop/mshop-aggr-prod/outer/v1/material/create/createAuth?appid=38741001&did=8e72f37ab5db201b91de47172047e760&noncestr=9908c3&svs=v3&timestamp=1734184261&37a6259cc0c1dae299a7866489dff0bd
MXSecurity.signV3 result=1181b2330a12f04c2501193430b50712d6f0187a2f87eaf0fe861016e2e1f6a7
MXSecurity.signV3 is called: url=https://zuul.aikucun.com/appconfigmgt/api/v1/download/config?appid=38741001&did=8e72f37ab5db201b91de47172047e760&noncestr=32a49b&svs=v3&timestamp=1734184263, nonceStr=32a49b, timestamp=1734184263, body=2288e58e8bda39d24cb10b10af923d50
[+] MessageDigest.digest(byte[]) called
Plaintext: appid=38741001&svs=v3&noncestr=32a49b&timestamp=1734184263&secret=04fdc5e4d9c7420e896ee92b17c68e9f&url=https://zuul.aikucun.com/appconfigmgt/api/v1/download/config?appid=38741001&did=8e72f37ab5db201b91de47172047e760&noncestr=32a49b&svs=v3&timestamp=1734184263&2288e58e8bda39d24cb10b10af923d50
MXSecurity.signV3 result=4d9b7d406b6ce2e44dc602b8c83a49b4b20ec944bea69d72aae3790249ed7127

libmsaoaidsec.so反调试及算法逆向案例(爱库存)