dedao G-Auth-Sign字段unidbg逆向

Java层

image-20220217112532603

app有加固，尝试使用frida_dump脱壳失败，使用blackdex32脱壳成功。

jdax打开，搜索G-Auth-Sign，没有结果。GDA打开，搜索G-Auth-Sign

image-20220216194527624

com.luojilab.netsupport.utils.b.a

image-20220216194708706

com.luojilab.netsupport.utils.b.a

image-20220216194810133

com.iget.baselib.BaseApi.calcSignature

image-20220216195122938

com.iget.baselib.BaseApi.init

image-20220216195147867

所以最后是调用了libbase-lib.so里的calcSignature函数

这时再回到jadx，打开com.luojilab.netsupport.utils.b.a

image-20220216195607411

将选项里的代码注释等级改为DEBUG（此项功能在旧版中没看到）

image-20220216195655513

保存后再查看

image-20220216195741604

虽然不是真实代码，但是已经能够看到G-Auth-Sign这个字符串了，最重要的是这个字符串能被搜索到。

至于calcSignature的输入，由于无法用frida进行hook，只能根据java代码进行构造。

so层

函数窗口搜索java，没有结果，说明是动态注册。打开JNI_OnLoad函数

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unidbg实现

public class Dedao extends AbstractJni {
    private final AndroidEmulator emulator;
    private final VM vm;
    private final Module module;

    public static String pkgName = "com.luojilab.player";
    public static String apkPath = "unidbg-android/src/test/java/com/dedao/dedao9100.apk";
    public static String soName = "base-lib";

    public Dedao() {
        emulator = AndroidEmulatorBuilder.for32Bit().setProcessName(pkgName).build();
        Memory memory = emulator.getMemory();
        memory.setLibraryResolver(new AndroidResolver(23));
        vm = emulator.createDalvikVM(new File(apkPath));
        vm.setJni(this);
        vm.setVerbose(true);
        DalvikModule dm = vm.loadLibrary(soName, true);
        module = dm.getModule();
        vm.callJNI_OnLoad(emulator, module);
    }

    @Override
    public DvmObject<?> callObjectMethodV(BaseVM vm, DvmObject<?> dvmObject, String signature, VaList vaList) {
        switch (signature) {
            case "java/util/Iterator->next()Ljava/lang/Object;": {
                Iterator it = (Iterator) dvmObject.getValue();
                return vm.resolveClass("java/util/Map$Entry").newObject(it.next());
            }
            case "java/util/Map$Entry->getKey()Ljava/lang/Object;": {
                Map.Entry entry = (Map.Entry) dvmObject.getValue();
                String key = (String) entry.getKey();
                return new StringObject(vm, key);
            }
            case "java/util/Map$Entry->getValue()Ljava/lang/Object;": {
                Map.Entry entry = (Map.Entry) dvmObject.getValue();
                byte[] barr = (byte[]) entry.getValue();
                return new ByteArray(vm, barr);
            }
        }
        return super.callObjectMethodV(vm, dvmObject, signature, vaList);
    }

    public void call_sign() {
        HashMap hashMap = new HashMap();
        hashMap.put("path", "/drlog/rule".getBytes());
        hashMap.put("method", "GET".getBytes());
        hashMap.put("query_string", "did=d5d994ea662e63f1".getBytes());
        hashMap.put("timestamp", "1645063949".getBytes());
        hashMap.put("nonce", "e4da34c23b39d8783e3ff265c42b7cf6".getBytes());
        hashMap.put("secret", "eyJhbGciOiJIUzUxMiIsInR5cCI6IkpXVCJ9.eyJhdWQiOiJpZ2V0Z2V0LmNvbSIsImV4cCI6MTY0NzY1NTk0OSwiaWF0IjoxNjQ1MDYzOTQ5LCJpc3MiOiJEREdXIEpXVCBNSURETEVXQVJFIiwibmJmIjoxNjQ1MDYzOTQ5LCJzdWIiOiIzNDk4OTg0NjIiLCJkZXZpY2VfaWQiOiIiLCJkZXZpY2VfdHlwZSI6IiJ9.knPHNdmEUqm0lp96SxB7vCp5xcfXPSXYVbQ-Tg-L88m4WM0yXPHkOmLyBzPqK0ni5erHTLvQyUgulQpoGeDSqg".getBytes());
//        hashMap.put("content-type", "".getBytes());
//        hashMap.put("body", "".getBytes());

        HashMap hashMap1 = new HashMap();
        hashMap1.put("Xi-App-Key", "android-9.10.0".getBytes());
        hashMap1.put("Xi-Uid", "349898462".getBytes());
        hashMap1.put("Xi-Thumb", "xl".getBytes());
        hashMap1.put("Xi-Dt", "phone".getBytes());
        hashMap1.put("Xi-Ov", "7.1.2".getBytes());
        hashMap1.put("Xi-Net", "wifi".getBytes());
        hashMap1.put("Xi-Os", "ANDROID".getBytes());
        hashMap1.put("Xi-D", "d5d994ea662e63f1".getBytes());
        hashMap1.put("Xi-Dv", "Pixel".getBytes());
        hashMap1.put("Xi-T", "json".getBytes());
        hashMap1.put("Xi-Chil", "7".getBytes());
        hashMap1.put("Xi-V", "2".getBytes());
        hashMap1.put("Xi-Av", "9.10.0".getBytes());
        hashMap1.put("Xi-Scr", "0".getBytes());
        hashMap1.put("Xi-Adv", "1".getBytes());
        hashMap1.put("Xi-Seid", "d5d994ea662e63f1".getBytes());
//        hashMap1.put("Xi-Span-Id", "".getBytes());
//        hashMap1.put("Xi-Trace-Id", "".getBytes());
//        hashMap1.put("Xi-Parent-Id", "".getBytes());

        List<Object> list = new ArrayList<>();
        list.add(vm.getJNIEnv());
        list.add(0);
        list.add(vm.addLocalObject(vm.resolveClass("java/util/Map").newObject(hashMap)));
        list.add(vm.addLocalObject(vm.resolveClass("java/util/Map").newObject(hashMap1)));
        Number ret = module.callFunction(emulator, 0x2a45, list.toArray());
    }

    public static void main(String[] args) {
        Dedao test = new Dedao();
        test.call_sign();
    }
}

image-20220217112507480

补环境过程省略。结果出来了，但是和抓包结果对不上，可能是有些环境没有初始化。

image-20220217100218324

可以看到有个init函数调用了initImp，查看引用。

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那就先调用一下initImp

public void call_init() {
    List<Object> list = new ArrayList<>(10);
    list.add(vm.getJNIEnv());
    list.add(0);
    list.add(vm.addLocalObject(vm.resolveClass("android/content/Context").newObject(null)));
    list.add(vm.addLocalObject(new StringObject(vm, "463ceba202a9f6f9ac4cd98d0f2f2876204ea85c")));
    module.callFunction(emulator, 0x2315, list.toArray());
}

public static void main(String[] args) {
    Dedao test = new Dedao();
    test.call_init();
    test.call_sign();
}

image-20220217112716896

和抓包结果一致。

unidbg逆向

查看calcSignature函数sub_2A44

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v2是最后的sign，它是sub_3A40的返回值，进去看看

image-20220217113218284

下断点看看输入

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所以输入的a2中已经保存着结果了。

image-20220217114519621

那就再往前追溯，看看sub_B198

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参数个数不太正常，看看跳转处的汇编

image-20220217113731518

只有3个入参，改改声明

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image-20220217113935846

函数最后处的调用也不太正常，看看汇编

image-20220217114045950

不太像个函数调用，按U将其转为数据，然后按C将其转为代码

image-20220217114254765

然后在0xB85C处按E将其标记为函数结尾，回到代码F5

image-20220217114944861

已经知道结果保存在a1[2]，而a1[2]=v63, v63=v75, v61=v75，所以看看sub_D98C

image-20220217115130069

下断点看看输入（该函数在initImp中也被调用了，需要注意一下）

image-20220217115327637

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可以看到a3正是其字节表示。继续往前追溯

image-20220217115611092

看看sub_CE48

image-20220217115725732

明显的HMAC特征，结合sign的长度，用的应该是HMAC-SHA1。

下断点看看输入（该函数有被多次调用，需要注意）

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image-20220217120052213

image-20220217120106076

将它们作为key和输入在cyberchef测一下

image-20220217120221589

和抓包结果一致。

unidbg代码

public class Dedao extends AbstractJni {
    private final AndroidEmulator emulator;
    private final VM vm;
    private final Module module;

    public static String pkgName = "com.luojilab.player";
    public static String apkPath = "unidbg-android/src/test/java/com/dedao/dedao9100.apk";
    public static String soName = "base-lib";

    public Dedao() {
        emulator = AndroidEmulatorBuilder.for32Bit().setProcessName(pkgName).build();
        Memory memory = emulator.getMemory();
        memory.setLibraryResolver(new AndroidResolver(23));
        vm = emulator.createDalvikVM(new File(apkPath));
        vm.setJni(this);
        vm.setVerbose(true);
        DalvikModule dm = vm.loadLibrary(soName, true);
        module = dm.getModule();
        vm.callJNI_OnLoad(emulator, module);
    }

    @Override
    public DvmObject<?> callObjectMethodV(BaseVM vm, DvmObject<?> dvmObject, String signature, VaList vaList) {
        switch (signature) {
            case "java/util/Iterator->next()Ljava/lang/Object;": {
                Iterator it = (Iterator) dvmObject.getValue();
                return vm.resolveClass("java/util/Map$Entry").newObject(it.next());
            }
            case "java/util/Map$Entry->getKey()Ljava/lang/Object;": {
                Map.Entry entry = (Map.Entry) dvmObject.getValue();
                String key = (String) entry.getKey();
                return new StringObject(vm, key);
            }
            case "java/util/Map$Entry->getValue()Ljava/lang/Object;": {
                Map.Entry entry = (Map.Entry) dvmObject.getValue();
                byte[] barr = (byte[]) entry.getValue();
                return new ByteArray(vm, barr);
            }
        }
        return super.callObjectMethodV(vm, dvmObject, signature, vaList);
    }

    public void call_sign() {
        HashMap hashMap = new HashMap();
        hashMap.put("path", "/drlog/rule".getBytes());
        hashMap.put("method", "GET".getBytes());
        hashMap.put("query_string", "did=d5d994ea662e63f1".getBytes());
        hashMap.put("timestamp", "1645063949".getBytes());
        hashMap.put("nonce", "e4da34c23b39d8783e3ff265c42b7cf6".getBytes());
        hashMap.put("secret", "eyJhbGciOiJIUzUxMiIsInR5cCI6IkpXVCJ9.eyJhdWQiOiJpZ2V0Z2V0LmNvbSIsImV4cCI6MTY0NzY1NTk0OSwiaWF0IjoxNjQ1MDYzOTQ5LCJpc3MiOiJEREdXIEpXVCBNSURETEVXQVJFIiwibmJmIjoxNjQ1MDYzOTQ5LCJzdWIiOiIzNDk4OTg0NjIiLCJkZXZpY2VfaWQiOiIiLCJkZXZpY2VfdHlwZSI6IiJ9.knPHNdmEUqm0lp96SxB7vCp5xcfXPSXYVbQ-Tg-L88m4WM0yXPHkOmLyBzPqK0ni5erHTLvQyUgulQpoGeDSqg".getBytes());
//        hashMap.put("content-type", "".getBytes());
//        hashMap.put("body", "".getBytes());

        HashMap hashMap1 = new HashMap();
        hashMap1.put("Xi-App-Key", "android-9.10.0".getBytes());
        hashMap1.put("Xi-Uid", "349898462".getBytes());
        hashMap1.put("Xi-Thumb", "xl".getBytes());
        hashMap1.put("Xi-Dt", "phone".getBytes());
        hashMap1.put("Xi-Ov", "7.1.2".getBytes());
        hashMap1.put("Xi-Net", "wifi".getBytes());
        hashMap1.put("Xi-Os", "ANDROID".getBytes());
        hashMap1.put("Xi-D", "d5d994ea662e63f1".getBytes());
        hashMap1.put("Xi-Dv", "Pixel".getBytes());
        hashMap1.put("Xi-T", "json".getBytes());
        hashMap1.put("Xi-Chil", "7".getBytes());
        hashMap1.put("Xi-V", "2".getBytes());
        hashMap1.put("Xi-Av", "9.10.0".getBytes());
        hashMap1.put("Xi-Scr", "0".getBytes());
        hashMap1.put("Xi-Adv", "1".getBytes());
        hashMap1.put("Xi-Seid", "d5d994ea662e63f1".getBytes());
//        hashMap1.put("Xi-Span-Id", "".getBytes());
//        hashMap1.put("Xi-Trace-Id", "".getBytes());
//        hashMap1.put("Xi-Parent-Id", "".getBytes());

        List<Object> list = new ArrayList<>();
        list.add(vm.getJNIEnv());
        list.add(0);
        list.add(vm.addLocalObject(vm.resolveClass("java/util/Map").newObject(hashMap)));
        list.add(vm.addLocalObject(vm.resolveClass("java/util/Map").newObject(hashMap1)));
        Number ret = module.callFunction(emulator, 0x2a45, list.toArray());
    }

    public void call_init() {
        List<Object> list = new ArrayList<>(10);
        list.add(vm.getJNIEnv());
        list.add(0);
        list.add(vm.addLocalObject(vm.resolveClass("android/content/Context").newObject(null)));
        list.add(vm.addLocalObject(new StringObject(vm, "463ceba202a9f6f9ac4cd98d0f2f2876204ea85c")));
        module.callFunction(emulator, 0x2315, list.toArray());
        System.out.println("=> Init");
    }

    public static void main(String[] args) {
        Dedao test = new Dedao();
        test.call_init();
        test.call_sign();
    }
}

其他

不能用frida进行hook的话逆向起来有点困难，不知道有什么方法解决。