安卓协议逆向 cxdx 分析与实现
2023-3-23 17:59:54 Author: 看雪学苑(查看原文) 阅读量:18 收藏


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看雪论坛作者ID:行简


Kit

app 版本:5.0.0
设备:K40 刷 piexl 11 rom
抓包工具:Charles
反汇编工具:JEB、JADX、IDA
inject:frida


抓包

POST /v1/api/app/login/doLogin HTTP/1.1X-OsVersion: 30User-Agent: Mozilla/5.0 (Linux; Android 11; M2012K11AC Build/RQ3A.211001.001; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/108.0.5359.128 Mobile Safari/537.36 CSDNApp/5.0.0(Android)wToken/0.0.1X-RandomNum: 54736X-Access-Token: 00871d5df0d4f51efb5883b3b2fd2359platform: androidX-Ca-Signature-Headers: X-Ca-Timestamp,X-Ca-Key,X-Ca-NonceAuthorization:X-OS: Androidc_appVersion: 5.0.0X-App-ID: CSDN-APPX-App-Theme: daycontent-type: application/json; charset=UTF-8X-Ca-Signature: BqhPpXbobBOndykiyCtOVK06GHLkfLbs1y4B3Ek0gnY=X-ConnectionType: WIFIUserToken:X-TimeStamp: 1671939318488Cookie: UserName=;UserToken=X-Ca-Key: 203789067Accept: application/jsonX-Device-ID: aid0f0fef992b53479187546b3c621157f0wToken: e447_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&ff4b_85475962D8E15A4E7AE60ED42FF3568E8EDB86EE620E495591X-DeviceModel: Redmi M2012K11ACversion: 5.0.0X-Ca-Nonce: be0eca5c-e959-4b0f-b4e7-22e00118157eX-Ca-Timestamp: 1671939318489X-Sign: 70B21B02FD0EFD2353F0D7F4F2E7CDB6FC1C3C42Host: passport.csdn.netConnection: Keep-AliveAccept-Encoding: gzipContent-Length: 95{"pwdOrVerifyCode":"123456","loginType":"1","userIdentification":"17750659921","checkAli":true}
意料之中一大堆参数,反复几次总结需分析的参数应该为以下几个:
X-Sign、wToken、X-Ca-Signature、X-Access-Token、X-Ca-Timestamp


分析

先搜索 X-Sign,就一处。

跟进得:
public static Map<String, String> z(String url, Map<String, String> requestMap) {    String str;    String a2 = wo3.a(CSDNApp.csdnApp);    HashMap hashMap = new HashMap();    hashMap.put("platform", "android");    hashMap.put("version", xn3.u());    hashMap.put("c_appVersion", xn3.u());    if (!TextUtils.isEmpty(it3.g())) {        hashMap.put("JWT-TOKEN", it3.g());        no3.a("==JWT-TOKEN==", it3.g());    }    hashMap.put("Authorization", StringUtils.isEmpty(it3.g()) ? "" : "Bearer " + it3.g());    hashMap.put("X-Device-ID", a2);    hashMap.put("X-OS", "Android");    hashMap.put("X-App-ID", "CSDN-APP");    hashMap.put("X-Access-Token", MD5.md5(a2 + "AndroidCSDN-APPb85fF96d-7Aa4-4Ec1-bf1D-2133c1A45656"));    hashMap.put("X-OsVersion", Build.VERSION.SDK_INT + "");    String str2 = Build.BRAND + Operators.SPACE_STR + Build.MODEL;    int length = str2.length();    for (int i = 0; i < length; i++) {        char charAt = str2.charAt(i);        if ((charAt <= 31 && charAt != '\t') || charAt >= 127) {            str2.replace(charAt, ' ');        }    }    hashMap.put("X-DeviceModel", str2);    hashMap.put("X-ConnectionType", yp3.b(CSDNApp.csdnApp));    hashMap.put("UserToken", StringUtils.isEmpty(it3.q()) ? "" : it3.q());    hashMap.put("X-App-Theme", CSDNApp.isDayMode ? "day" : "night");    int c2 = xn3.c(10000, 99999);    String str3 = new Date().getTime() + "";    try {        str = mq3.a(a2 + c2 + str3 + zf1.o);    } catch (DigestException e2) {        e2.printStackTrace();        str = "";    }    hashMap.put("X-Sign", str);    hashMap.put("X-RandomNum", c2 + "");    hashMap.put("X-TimeStamp", str3);    StringBuilder sb = new StringBuilder();    sb.append("UserName=");       sb.append(it3.p());    sb.append(";UserToken=");    sb.append(StringUtils.isEmpty(it3.q()) ? "" : it3.q());    hashMap.put(IWebview.COOKIE, sb.toString());    if (!StringUtils.isEmpty(url) && requestMap != null && requestMap.containsKey("category")) {        hashMap.put("X-PageKey", "blog." + requestMap.get("category"));        hashMap.put("X-Path", "app.csdn.net/blog/" + requestMap.get("category"));    }    if (!StringUtils.isEmpty(url) && url.equals(s22.G0)) {        hashMap.put("X-PageKey", vr3.Q6);        hashMap.put("X-Path", "app.csdn.net/blog/detail");        if (requestMap != null && requestMap.containsKey("from")) {            hashMap.put("X-Referer", "blog." + requestMap.get("from"));        }    }    hashMap.put("User-Agent", CSDNApp.csdnApp.userAgent + " CSDNApp/" + xn3.u() + "(Android)wToken/0.0.1");    try {        hashMap.put("wToken", TigerTallyAPI.vmpSign(1, str3.getBytes("UTF-8")));    } catch (UnsupportedEncodingException e3) {        e3.printStackTrace();    }    return hashMap;}
pretty nice,很多参数都在这里,那就从上往下分析:
hashMap.put("platform", "android"); // 固定值hashMap.put("version", xn3.u()); // 固定值hashMap.put("c_appVersion", xn3.u()); // 固定值hashMap.put("Authorization", StringUtils.isEmpty(it3.g()) ? "" : "Bearer " + it3.g()); // 无用,请求头中为空hashMap.put("X-Device-ID", a2); // a2 在 String a2 = wo3.a(CSDNApp.csdnApp);
hook wo3.a看看:
function main() {    Java.perform(function () {        var wo3 = Java.use("wo3");        wo3["a"].implementation = function (context) {            console.log('a is called' + ', ' + 'context: ' + context);            var ret = this.a(context);            console.log('a ret value is ' + ret);            return ret;        };    });}setImmediate(main)
结果:
a is called, context: net.csdn.csdnplus.CSDNApp@dc96acba ret value is aid0f0fef992b53479187546b3c621157f0
多次 hook 该值并没有改变,查看不同数据包的内容也是一样的,但在 Java 层仅分析到 aid 复制点,后面数据同一设备都是一样的,怀疑是消息散列值,有可能是 DeviceID 或者 UUID,有在 Java 层看到,但 hook 不到,往下分析:
hashMap.put("X-OS", "Android"); // 固定值hashMap.put("X-App-ID", "CSDN-APP"); // 固定值hashMap.put("X-Access-Token", MD5.md5(a2 + "AndroidCSDN-APPb85fF96d-7Aa4-4Ec1-bf1D-2133c1A45656")); // a2 就是上面的 X-Device-ID 再进行加盐处理后进行 MD5 加密复现一下:
from hashlib import md5 def encrypt_md5(mes):    new_md5 = md5()    # 这里必须用encode()函数对字符串进行编码,不然会报 TypeError: Unicode-objects must be encoded before hashing    new_md5.update(mes.encode(encoding='utf-8'))    # 加密    return new_md5.hexdigest() if __name__ == '__main__':    print(encrypt_md5('aid0f0fef992b53479187546b3c621157f0AndroidCSDN-APPb85fF96d-7Aa4-4Ec1-bf1D-2133c1A45656'))
结果 00871d5df0d4f51efb5883b3b2fd2359,校验无误,继续往下:
hashMap.put("X-OsVersion", Build.VERSION.SDK_INT + ""); // sdk 版本吧,可随机的样子hashMap.put("X-DeviceModel", str2); // 通过上面获取来的,分析一下就是手机 + 手机名称hashMap.put("X-ConnectionType", yp3.b(CSDNApp.csdnApp)); // 网络连接类型hashMap.put("UserToken", StringUtils.isEmpty(it3.q()) ? "" : it3.q()); // 抓包为空值,放弃hashMap.put("X-App-Theme", CSDNApp.isDayMode ? "day" : "night"); // 主题模式hashMap.put("X-Sign", str);
str 是上面计算来的,拿来分析下:
int c2 = xn3.c(10000, 99999);String str3 = new Date().getTime() + "";try {    str = mq3.a(a2 + c2 + str3 + zf1.o);} catch (DigestException e2) {    e2.printStackTrace();    str = "";}hashMap.put("X-Sign", str);
c2:10000 - 99999 之间的随机值;str3:时间戳转字符串;a2:上面分析过为 X-Device-ID 值;zf1.o:跟进查看为定值:public static final String o = "F403F982CA92F73AC142D50FFA69853D";
参数搞定,看 mq3.a 方法:
public static String a(String decrypt) throws DigestException {    try {        MessageDigest messageDigest = MessageDigest.getInstance("SHA-1");        messageDigest.update(decrypt.getBytes());        byte[] digest = messageDigest.digest();        StringBuffer stringBuffer = new StringBuffer();        for (byte b : digest) {            String hexString = Integer.toHexString(b & 255);            if (hexString.length() < 2) {                stringBuffer.append(0);            }            stringBuffer.append(hexString);        }        return stringBuffer.toString().toUpperCase();    } catch (NoSuchAlgorithmException e) {        e.printStackTrace();        throw new DigestException("签名错误!");    }}
SHA1算法,先 hook 再还原:
function main() {    Java.perform(function () {        var mq3 = Java.use("mq3");        mq3["a"].implementation = function (decrypt) {            console.log('a is called' + ', ' + 'decrypt: \n' + decrypt);            var ret = this.a(decrypt);            console.log('a ret value is ' + ret);            return ret;        };    });}setImmediate(main)// frida -FU -l CSDN/csdn.js
结果:
a is called, decrypt:aid0f0fef992b53479187546b3c621157f0709751671957807054F403F982CA92F73AC142D50FFA69853Da ret value is E11539C9183644EEB69C7FEBAC1D58A2D874895C
还原:
import hashlib # 使用sha1加密算法,返回str加密后的字符串def sha1_secret_str(s: str):    sha = hashlib.sha1(s.encode('utf-8'))    encrypts = sha.hexdigest()    return encrypts.upper() if __name__ == '__main__':    # 待加密的字符串    s = 'aid0f0fef992b53479187546b3c621157f0709751671957807054F403F982CA92F73AC142D50FFA69853D'    res = sha1_secret_str(s)    print(res)
结果:E11539C9183644EEB69C7FEBAC1D58A2D874895C 校验无误,继续往下分析:
hashMap.put("X-RandomNum", c2 + ""); // 10000 - 99999 之间的随机值;hashMap.put("X-TimeStamp", str3); // str3:时间戳转字符串;hashMap.put(IWebview.COOKIE, sb.toString()); // 看抓包结果应该是 Cookie 值,对照结果 UserName=;UserToken= 啥操作没做,应该是要登录后才有值也是固定值hashMap.put("User-Agent", CSDNApp.csdnApp.userAgent + " CSDNApp/" + xn3.u() + "(Android)wToken/0.0.1");
对照其抓包内容:CSDNApp.csdnApp.userAgent 获取设备 header,xn3.u() 获取 app 版本号。
// Mozilla/5.0 (Linux; Android 11; M2012K11AC Build/RQ3A.211001.001; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/108.0.5359.128 Mobile Safari/537.36 CSDNApp/5.0.0(Android)wToken/0.0.1hashMap.put("wToken", TigerTallyAPI.vmpSign(1, str3.getBytes("UTF-8")));
看到 wToken 就有点不好的预感,应该是阿里安全的,前段时间很火的某box就是用的这个,跟进看看,最终定位到:
private static native String _genericNt3(int i, byte[] bArr);
so 层了,放着先看看别的参数吧,这块代码,能解决的参数都解决了,但 X-Ca-Signature 没在这出现,jadx 再搜跟到以下代码:
private static Map<String, String> c(StringBuilder strBuilder, Map<String, String> headerParams) {    if (ft3.b() != 1) {        headerParams.put("X-Ca-Stage", ft3.b() == 2 ? "TEST" : "PRE");    }    try {        Mac mac = Mac.getInstance("HmacSHA256");        byte[] bytes = y12.c.getBytes("UTF-8");        mac.init(new SecretKeySpec(bytes, 0, bytes.length, "HmacSHA256"));        String str = new String(Base64.encodeBase64(mac.doFinal(strBuilder.toString().getBytes("UTF-8"))));        headerParams.put("X-Ca-Signature", str);        no3.a("==HmacSHA256==", str);    } catch (UnsupportedEncodingException e2) {        e2.printStackTrace();    } catch (InvalidKeyException e3) {        e3.printStackTrace();    } catch (NoSuchAlgorithmException e4) {        e4.printStackTrace();    }    return headerParams;}
不难看出该值是通过 HmacSHA256 加密后再进行 Base64 编码后得到的结果,其 key 值为:
public static final String c = "0u94vkvsewic9kkgsp1r3nuq3ir0lv3n";hook 看看要加密 strBuilder 有啥:function main() {    Java.perform(function () {        var r12 = Java.use("r12");        r12["c"].implementation = function (strBuilder, headerParams) {            console.log('strBuilder: \n' + strBuilder);            var ret = this.c(strBuilder, headerParams);            var keyset = ret.keySet();            var result = "";            var it = keyset.iterator();            while (it.hasNext()) {                var keystr = it.next().toString();                var valuestr = ret.get(keystr).toString();                console.log(keystr)                console.log(valuestr)                result += valuestr;            }            return ret;        };    });}setImmediate(main)// frida -FU -l CSDN/csdn.js
结果:
strBuilder:POSTapplication/jsonapplication/json; charset=UTF-8X-Ca-Key:203789067X-Ca-Nonce:3339aae3-e295-410c-8345-52c9ebc56b5aX-Ca-Timestamp:1671963564343/v1/api/app/login/doLogin
其中 X-Ca-Key 是个定值:
headerParams.put("X-Ca-Key", y12.b);public static final String b = "203789067";X-Ca-NonceUUID 值:headerParams.put("X-Ca-Nonce", UUID.randomUUID().toString());X-Ca-Timestamp 为时间戳。
python还原算法,与抓包结果一致:
from hashlib import sha256import hmac, base64 def get_sign(data, key):    key = key.encode('utf-8')    message = data.encode('utf-8')    sign = base64.b64encode(hmac.new(key, message, digestmod=sha256).digest()).decode()    print(sign)    return signif __name__ == '__main__':    # 待加密的字符串    s = "POST" + "\n" + \        "application/json" + "\n" + \        "\n" + \        "application/json; charset=UTF-8" + "\n" + \        "\n" + \        "X-Ca-Key:203789067" + "\n" + \        "X-Ca-Nonce:3339aae3-e295-410c-8345-52c9ebc56b5a" + "\n" + \        "X-Ca-Timestamp:1671963564343" + "\n" + \        "/v1/api/app/login/doLogin"    k = '0u94vkvsewic9kkgsp1r3nuq3ir0lv3n'    res = get_sign(s, k)    print(res)
抓包结果:QJYeguZxkE+ZojwTP0rIJ+IzjaSHI82uR2y0xOIG35U=
到这几乎参数都解决了,剩个 so 层的 wtoken,在 Java 层能够定位到:com/aliyun/TigerTally/TigerTallyAPI,其中,要找的就是 libtiger_tally.so 了:
static {    System.loadLibrary("tiger_tally");}
换思路做吧,不想折腾,想了想我直接 rpc 调用不就好了。


rpc 远程调用

frida rpc 脚本:
var response = null;Java.enumerateClassLoaders({    onMatch: function (loader) {        try {            if (loader.findClass("com.aliyun.TigerTally.TigerTallyAPI")) {                Java.classFactory.loader = loader;                response = Java.use("com.aliyun.TigerTally.TigerTallyAPI")            } else {            }        } catch (error) {        }    }, onComplete: function () {    }}); function stringToByte (str) {     var ch, st, re = [];     for (var i = 0; i < str.length; i++ ) {           ch = str.charCodeAt(i);          st = [];               do {                 st.push( ch & 0xFF );             ch = ch >> 8;          } while ( ch );        re = re.concat(st.reverse());      }     return re;} function getwwoken(data){    var result = response._genericNt3(1, stringToByte(data));    return result;} rpc.exports = {    getwtoken:getwwoken}
补环境:
import timeimport hmacimport uuidimport randomimport base64from hashlib import sha256, md5, sha1 def get_x_osversion():    return "30" def get_x_os():    return "android" def get_x_appid():    return "CSDN_APP" def get_x_app_theme():    return "day" def get_x_connection_type():    return "WIFI" def get_x_timestramp():    return str(int(time.time() * 1000)) def get_x_device_model():    return "Redmi M2012K11AC" def get_x_ca_Signature_Headers():    return "X-Ca-Timestamp,X-Ca-Key,X-Ca-Nonce" def get_User_Agent():    return "Mozilla/5.0 (Linux; Android 11; M2012K11AC Build/RQ3A.211001.001; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/108.0.5359.128 Mobile Safari/537.36 CSDNApp/5.0.0(Android)wToken/0.0.1" def get_x_ca_nonce():    return str(uuid.uuid4()) def get_x_device_id():    return "aid0f0fef992b53479187546b3c621157f0" def get_access_token():    X_Access_Token = "aid0f0fef992b53479187546b3c621157f0AndroidCSDN-APPb85fF96d-7Aa4-4Ec1-bf1D-2133c1A45656"    md5_mes = md5(X_Access_Token.encode())    return md5_mes.hexdigest() x_timestramp = get_x_timestramp()x_ca_nonce = get_x_ca_nonce()def get_x_randomnum():    return str(random.randint(10000, 99999)) def get_x_ca_signature():    data = "POST" + "\n" + \        "application/json" + "\n" + \        "\n" + \        "application/json; charset=UTF-8" + "\n" + \        "\n" + \        "X-Ca-Key:203789067" + "\n" + \        "X-Ca-Nonce:3339aae3-e295-410c-8345-52c9ebc56b5a" + "\n" + \        "X-Ca-Timestamp:1671963564343" + "\n" + \        "/v1/api/app/login/doLogin"    key = "0u94vkvsewic9kkgsp1r3nuq3ir0lv3n".encode("utf-8")    message = data.encode("utf-8")    sign = base64.b64encode(hmac.new(key, message, digestmod=sha256).digest())    return str(sign, 'utf-8'), x_timestramp, x_ca_nonce def get_xsign():    xsign_mes = get_x_device_id() + get_x_randomnum() + x_timestramp + "F403F982CA92F73AC142D50FFA69853D"    return sha1(xsign_mes.encode("utf-8")).hexdigest().upper()
远程调用:
import fridafrom login_env import *import requests def on_message(message, data):    print("[%s] => %s" % (message, data)) def inject_hook():    session = frida.get_usb_device().attach('net.csdn.csdnplus')    with open('CSDN/rpc.js', 'r') as f:        js_code = f.read()    script = session.create_script(js_code)    script.on('message', on_message)    script.load()    return script def message(message, data):    if message["type"] == 'send':        print("[*] {0}".format(message['payload']))    else:        print(message) def req():    url = "https://passport.csdn.net/v1/api/app/login/doLogin"    headers = {        "X-OsVersion": "30",        "User-Agent": "Mozilla/5.0 (Linux; Android 11; M2012K11AC Build/RQ3A.211001.001; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/108.0.5359.128 Mobile Safari/537.36 CSDNApp/5.0.0(Android)wToken/0.0.1",        "X-RandomNum": get_x_randomnum(),        "X-Access-Token": get_access_token(),        "platform": "android",        "X-Ca-Signature-Headers": "X-Ca-Timestamp,X-Ca-Key,X-Ca-Nonce",        "Authorization": "",        "X-OS": "Android",        "c_appVersion": "5.0.0",        "X-App-ID": "CSDN-APP",        "X-App-Theme": "day",        "content-type": "application/json; charset=UTF-8",        "X-Ca-Signature": get_x_ca_signature()[0],        "X-ConnectionType": "WIFI",        "UserToken": "",        "X-TimeStamp": get_x_ca_signature()[1],        "X-Ca-Key": "203789067",        "Accept": "application/json",        "X-Device-ID": get_x_device_id(),        "wToken": res,        "X-DeviceModel": "Redmi M2012K11AC",        "version": "5.0.0",        "X-Ca-Nonce": get_x_ca_signature()[2],        "X-Ca-Timestamp": get_x_ca_signature()[1],        "X-Sign": get_xsign(),        "Host": "passport.csdn.net",        "Connection": "Keep-Alive",        "Accept-Encoding": "gzip",    }    data = {"pwdOrVerifyCode":"123456","loginType":"1","userIdentification":"17750659921","checkAli":"true"}    response = requests.post(url, headers=headers,json=data)    print(response.text)  if __name__ == '__main__':    rpc_script = inject_hook()    res = rpc_script.exports.getwtoken(get_x_ca_signature()[1])    req()'''
结果,校验一致:
{"message":"用户名或密码错误","status":false,"code":"1039"}

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