一、目標(biāo)
有一段時間沒有寫unidbg相關(guān)的文章了,這個樣本挺合適却音,難度適中改抡,還適當(dāng)給你挖個小坑。所以后面是一個系列文章系瓢,包含 unidbg補環(huán)境阿纤,Trace Block 對比流程,Trace Code定位差異夷陋。掌握好這一系列套路欠拾,Native分析可以算入門了。
這次先來把so用unidbg跑通
v6.1.0
二骗绕、步驟
Dump so
IDA打開 libencrypt.so 去到我們要分析的兩個函數(shù) checkcode 和 decheckcode 對應(yīng)的偏移地址 0x24424 , 0x2B1BC 藐窄。會發(fā)現(xiàn)一個奇怪的問題,這兩個地址上沒有匯編代碼酬土,都是 0x00荆忍。
估計是殼給我們加戲了,他把這兩個關(guān)鍵函數(shù)的部分代碼給抽取了撤缴,等到運行的時候才會補回去刹枉,這樣就阻礙你去靜態(tài)分析這個so。
不過殼怎么加戲屈呕,運行的時候是一定會在內(nèi)存中存在完整的代碼的微宝,否則App是跑不起來的。
所以我們也加戲虎眨,Dump 之
function dumpSo(){
var libxx = Process.getModuleByName("libencrypt.so");
console.log("*****************************************************");
console.log(TAG + "name: " +libxx.name);
console.log(TAG + "base: " +libxx.base);
console.log(TAG + "size: " +ptr(libxx.size));
var file_path = "/data/data/com.xxx.aeri.caranywhere/" + libxx.name + "_" + libxx.base + "_" + ptr(libxx.size) + ".so";
console.log(TAG + file_path);
var file_handle = new File(file_path, "wb");
if (file_handle && file_handle != null) {
Memory.protect(ptr(libxx.base), libxx.size, 'rwx');
var libso_buffer = ptr(libxx.base).readByteArray(libxx.size);
file_handle.write(libso_buffer);
file_handle.flush();
file_handle.close();
console.log(TAG + "[dump]:", file_path);
}
}
unidbg run so 基本框架
dump出so的完整代碼了蟋软,我們開始撘unidbg run so的基本框架。unidbg的庫代碼可以從原作者的github上下載最新的专甩。
public class CaranywhereDemo extends AbstractJni {
public AndroidEmulator emulator;
public VM vm;
public Module module;
public DvmClass dvmClass;
public static void main(String[] args) throws DecoderException, IOException {
String apkPath = "/Users/fenfei/Desktop/xxx/6.1.0.apk";
CaranywhereDemo carObj = new CaranywhereDemo(apkPath);
carObj.destroy();
}
public CaranywhereDemo(String apkFilePath) throws DecoderException, IOException {
//*
emulator = AndroidEmulatorBuilder.for64Bit()
.setProcessName("com.xxx.aeri.caranywhere")
.addBackendFactory(new Unicorn2Factory(true))
.build(); // 創(chuàng)建模擬器實例钟鸵,要模擬32位或者64位,在這里區(qū)分
//*/
// 多線程處理 true的情況下 在 faccessat 的時候就卡死涤躲, 所以關(guān)掉, 這個樣本暫時也不需要多線程
emulator.getSyscallHandler().setEnableThreadDispatcher(false);
final Memory memory = emulator.getMemory(); // 模擬器的內(nèi)存操作接口
memory.setLibraryResolver(new AndroidResolver(23)); // 設(shè)置系統(tǒng)類庫解析
vm = emulator.createDalvikVM(new File(apkFilePath)); // 創(chuàng)建Android虛擬機
vm.setJni(this);
vm.setVerbose(true); // 設(shè)置是否打印Jni調(diào)用細(xì)節(jié)
new JniGraphics(emulator, vm).register(memory);
new AndroidModule(emulator, vm).register(memory);
dvmClass = vm.resolveClass("com/bangcle/comapiprotect/CheckCodeUtil");
DalvikModule dm = vm.loadLibrary("encrypt", false);
module = dm.getModule();
dm.callJNI_OnLoad(emulator);
}
private void destroy() {
try {
emulator.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
一個unidbg的Hello World就是這樣棺耍,先別著急跑它,之前我們說過种樱,so的關(guān)鍵代碼被抽取了蒙袍,所以不能直接跑so。得換成我們dump出來的結(jié)果嫩挤。
// DalvikModule dm = vm.loadLibrary("encrypt", false);
DalvikModule dm = vm.loadLibrary(new File("/Users/fenfei/Desktop/work/blogCode/xxx/libencrypt.so_0x7634ee7000_0x1d6000.so"), false);
一步一步補unidbg run so環(huán)境
先看第一個錯誤
[07:17:09 068] WARN [com.github.unidbg.linux.ARM64SyscallHandler] (ARM64SyscallHandler:384) - handleInterrupt intno=2, NR=30, svcNumber=0x16e, PC=unidbg@0xfffe0774, LR=RX@0x40018c9c[libencrypt.so]0x18c9c, syscall=null
java.lang.UnsupportedOperationException: android/app/ActivityThread->currentActivityThread()Landroid/app/ActivityThread;
at com.github.unidbg.linux.android.dvm.AbstractJni.callStaticObjectMethod(AbstractJni.java:432)
at com.github.unidbg.linux.android.dvm.AbstractJni.callStaticObjectMethod(AbstractJni.java:421)
at com.github.unidbg.linux.android.dvm.DvmMethod.callStaticObjectMethod(DvmMethod.java:59)
at com.github.unidbg.linux.android.dvm.DalvikVM64$111.handle(DalvikVM64.java:1723)
at com.github.unidbg.linux.ARM64SyscallHandler.hook(ARM64SyscallHandler.java:130)
unidbg的報錯提示非常清晰害幅,說明在 callStaticObjectMethod 中調(diào)用 ActivityThread 類的靜態(tài)方法 currentActivityThread,并且返回值是 ActivityThread 類型岂昭。
我們在CaranywhereDemo.java中重載 callStaticObjectMethod 函數(shù)來解決這個問題:
@Override
public DvmObject<?> callStaticObjectMethod(BaseVM vm, DvmClass dvmClass, String signature, VarArg varArg) {
switch (signature) {
case "android/app/ActivityThread->currentActivityThread()Landroid/app/ActivityThread;":
return vm.resolveClass("android/app/ActivityThread").newObject(null);
}
return super.callStaticObjectMethod(vm, dvmClass, signature, varArg);
}
我們先不關(guān)心這個 currentActivityThread 要被做什么用以现,直接返回一個空的類就行。
繼續(xù)跑,下一個錯誤還是在 callStaticObjectMethod 里面邑遏,看上去像是獲取 一些系統(tǒng)信息
java.lang.UnsupportedOperationException: android/os/SystemProperties->get(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String;
at com.github.unidbg.linux.android.dvm.AbstractJni.callStaticObjectMethod(AbstractJni.java:432)
at com.fenfei.test.CaranywhereDemo.callStaticObjectMethod(CaranywhereDemo.java:78)
at com.github.unidbg.linux.android.dvm.AbstractJni.callStaticObjectMethod(AbstractJni.java:421)
at com.github.unidbg.linux.android.dvm.DvmMethod.callStaticObjectMethod(DvmMethod.java:59)
at com.github.unidbg.linux.android.dvm.DalvikVM64$111.handle(DalvikVM64.java:1723)
at com.github.unidbg.linux.ARM64SyscallHandler.hook(ARM64SyscallHandler.java:130)
補這中有入?yún)⒌暮瘮?shù)可以簡單粗暴的給他返回一個空字符串佣赖,但是講究人先要把他的入?yún)⒋蛴〕鰜怼?/p>
@Override
public DvmObject<?> callStaticObjectMethod(BaseVM vm, DvmClass dvmClass, String signature, VarArg varArg) {
switch (signature) {
case "android/os/SystemProperties->get(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/String;":
System.out.println("android/os/SystemProperties->get 入?yún)ⅲ? + varArg.formatArgs());
return new StringObject(vm, "705KPGS001091");
case "android/app/ActivityThread->currentActivityThread()Landroid/app/ActivityThread;":
return vm.resolveClass("android/app/ActivityThread").newObject(null);
}
return super.callStaticObjectMethod(vm, dvmClass, signature, varArg);
}
Tip:
unidbg庫函數(shù)formatArgs提示不是公有函數(shù),在VarArg類里面改下 public final String formatArgs()
輸出
android/os/SystemProperties->get 入?yún)ⅲ?ro.serialno", "unknown"
原來是為了獲取Android序列號记盒,隨便給他編一個就好憎蛤, 由于本樣本只調(diào)用一次,所以就懶得判斷入?yún)⒘恕?/p>
Tip:
adb shell getprop ro.serialno 可以獲取到Android序列號
這個報錯和第一個報錯類似纪吮,不過它是在 callObjectMethod 函數(shù)里面
java.lang.UnsupportedOperationException: android/app/ActivityThread->getSystemContext()Landroid/app/ContextImpl;
at com.github.unidbg.linux.android.dvm.AbstractJni.callObjectMethod(AbstractJni.java:921)
at com.github.unidbg.linux.android.dvm.AbstractJni.callObjectMethod(AbstractJni.java:855)
at com.github.unidbg.linux.android.dvm.DvmMethod.callObjectMethod(DvmMethod.java:74)
at com.github.unidbg.linux.android.dvm.DalvikVM64$31.handle(DalvikVM64.java:504)
at com.github.unidbg.linux.ARM64SyscallHandler.hook(ARM64SyscallHandler.java:130)
重載 callObjectMethod 函數(shù)俩檬,然后 直接返回 ContextImpl 類型就行
public DvmObject<?> callObjectMethod(BaseVM vm, DvmObject<?> dvmObject, String signature, VarArg varArg) {
switch (signature) {
case "android/app/ActivityThread->getSystemContext()Landroid/app/ContextImpl;":
return vm.resolveClass("android/app/ContextImpl").newObject(null);
}
return super.callObjectMethod(vm, dvmObject, signature, varArg);
}
繼續(xù)報錯,這個是獲取包管理類
java.lang.UnsupportedOperationException: android/app/ContextImpl->getPackageManager()Landroid/content/pm/PackageManager;
at com.github.unidbg.linux.android.dvm.AbstractJni.callObjectMethod(AbstractJni.java:921)
at com.fenfei.test.CaranywhereDemo.callObjectMethod(CaranywhereDemo.java:91)
at com.github.unidbg.linux.android.dvm.AbstractJni.callObjectMethod(AbstractJni.java:855)
at com.github.unidbg.linux.android.dvm.DvmMethod.callObjectMethod(DvmMethod.java:74)
at com.github.unidbg.linux.android.dvm.DalvikVM64$31.handle(DalvikVM64.java:504)
at com.github.unidbg.linux.ARM64SyscallHandler.hook(ARM64SyscallHandler.java:130)
callObjectMethod 構(gòu)造 PackageManager類返回
case "android/app/ContextImpl->getPackageManager()Landroid/content/pm/PackageManager;":
return vm.resolveClass("android/content/pm/PackageManager").newObject(null);
下一個報錯碾盟。
java.lang.UnsupportedOperationException: android/app/ContextImpl->getSystemService(Ljava/lang/String;)Ljava/lang/Object;
at com.github.unidbg.linux.android.dvm.AbstractJni.callObjectMethod(AbstractJni.java:921)
at com.fenfei.test.CaranywhereDemo.callObjectMethod(CaranywhereDemo.java:93)
at com.github.unidbg.linux.android.dvm.AbstractJni.callObjectMethod(AbstractJni.java:855)
at com.github.unidbg.linux.android.dvm.DvmMethod.callObjectMethod(DvmMethod.java:74)
這個函數(shù)有參數(shù)棚辽,老規(guī)矩,打印下參數(shù)看看巷疼。
case "android/app/ContextImpl->getSystemService(Ljava/lang/String;)Ljava/lang/Object;":
System.out.println("android/app/ContextImpl->getSystemService 入?yún)ⅲ? + varArg.formatArgs());
return vm.resolveClass("java/lang/Object").newObject(null);
參數(shù)打印出來是
android/app/ContextImpl->getSystemService 入?yún)ⅲ?wifi"
估摸是wifi相關(guān)晚胡,先給他返回一個空的 Object再說
后面兩個報錯就是獲取wifi Mac地址相關(guān)的,直接補上
case "android/net/wifi/WifiInfo->getMacAddress()Ljava/lang/String;":
return new StringObject(vm, "00:00:00:00:00:00");
case "java/lang/Object->getConnectionInfo()Landroid/net/wifi/WifiInfo;":
return vm.resolveClass("android/net/wifi/WifiInfo").newObject(null);
到這里終于把 JNI_OnLoad 給跑通了嚼沿, 可以干一杯了。
call checkcode
搞了半天才開始進入正題瓷患,我們來調(diào)用 checkcode
public void callA() {
String strA = "F{"appInnerVersion":"125","appOutVersion":"6.1.0","deviceType":0,"imeiMD5":"EE6431DEBB1E02FE469FA5E8467CD693","mobileModel":"GOOGLE PIXEL 2 XL","softType":"0"}";
String strC = "1662109202156";
String methodName = "checkcode(Ljava/lang/String;ILjava/lang/String;)Ljava/lang/String;";
DvmObject ret = dvmClass.callStaticJniMethodObject(emulator, methodName,strA,1,strC);
String strOut = (String)ret.getValue();
System.out.println("call checkcode: " + strOut);
}
又有新的報錯了
java.lang.UnsupportedOperationException: android/os/Build->MODEL:Ljava/lang/String;
at com.github.unidbg.linux.android.dvm.AbstractJni.getStaticObjectField(AbstractJni.java:103)
at com.github.unidbg.linux.android.dvm.AbstractJni.getStaticObjectField(AbstractJni.java:53)
at com.github.unidbg.linux.android.dvm.DvmField.getStaticObjectField(DvmField.java:106)
at com.github.unidbg.linux.android.dvm.DalvikVM64$142.handle(DalvikVM64.java:2228)
這次要重載 getStaticObjectField 類了
public DvmObject<?> getStaticObjectField(BaseVM vm, DvmClass dvmClass, String signature) {
switch (signature){
case "android/os/Build$VERSION->SDK:Ljava/lang/String;":
return new StringObject(vm, "23");
case "android/os/Build->MANUFACTURER:Ljava/lang/String;":
return new StringObject(vm, "Google");
case "android/os/Build->MODEL:Ljava/lang/String;":
return new StringObject(vm, "pixel");
}
return super.getStaticObjectField(vm,dvmClass,signature);
}
這幾個值比較簡單骡尽,都是字符串型,我們給他賦值一把擅编。
耶攀细,大功告成了
call checkcode: FDAEKCAcOAQcNBgkEAwoCDQgEDQ4JBAgAAA4ODgcJBgkKBwYPBwwEBw4LBwsODQcFDQMMCAUJDAcEDQsADwEDDAIGDgQJAQYNDggNDQsCAQcNAwwIBQkMBwQNCwAPAQMMDQYCDAgBBQwGBAUIAwULBAoHBg8HDAQHDgsHCw4NBwUPAwEADAkPBQcODAcDDgYCDwMJCQUEAAgHDAUIBwEDBwMKDgcGBg4NDAgLBAAEAw8PAwEADAkPBQcODAcDDgYCCAQNDgkECAAADg4OBwkGCQIIAwkLBgACCgoGAgcCAwEMAQoIBw4BBw0GCQQDCgINDwMBAAwJDwUHDgwHAw4GAggHBwEMBAAAAwMJDQUDDQECBg4ECQEGDQ4IDQ0LAgEHDw0ADwMJDgQICAsJAgILBw8NAA8DCQ4ECAgLCQICCwcNBgIMCAEFDAYEBQgDBQsEAgYOBAkBBg0OCA0NCwIBBw==
先別高興的太早了,這個結(jié)果怎么看都有點不對勁爱态,和我們hook的結(jié)果相差有點大谭贪。
怎么判斷結(jié)果是對是錯?怎么和app對比來拿到正確的結(jié)果锦担? 等待下次的 Trace Block 和 Trace Code 教程吧俭识。
三、總結(jié)
unidbg補環(huán)境實際是考驗?zāi)愕腁ndroid編程能力洞渔。
谷歌一下關(guān)鍵字 unidbg + 報錯信息套媚,一般都有同道趟過坑。
什么磁椒?你打不開谷歌堤瘤?我現(xiàn)在勸你改行還來得及嗎?
1:ffshow
好味止園葵浆熔,大歡止稚子本辐。平生不止酒,止酒情無喜。