Tags: rev apk
Rating:
# 1337 Skills
```
App: https://play.google.com/store/apps/details?id=com.progressio.wildskills
Connection: nc 88.198.154.132 7002
```
This is an Android reversing challenge. We can download the [apk here.](https://apkpure.com/es/wild-skills/com.progressio.wildskills)
The app request an activation code to start using it. Let's dissasembly the apk in other to get those codes.
## JADX
Let's open the apk with [jadx.](https://github.com/skylot/jadx)
In the **MainActivity** we see this function:
```java
public void activateApp(View view) {
int i;
try {
i = Integer.parseInt(this.editTextActivation.getText().toString());
} catch (NumberFormatException unused) {
i = -1;
}
Calendar instance = Calendar.getInstance();
if (i == ((int) (Math.pow((double) (instance.get(3) * instance.get(1)), 2.0d) % 999983.0d))) {
findViewById(R.id.scrollViewActivation).setVisibility(4);
((InputMethodManager) getSystemService("input_method")).hideSoftInputFromWindow(this.editTextActivation.getWindowToken(), 0);
SharedPreferences.Editor edit = this.prefsmain.edit();
edit.putBoolean("Activated", true);
long time = new Date().getTime();
edit.putLong("Installed", time);
edit.putLong("ActivationDate", time);
edit.commit();
return;
}
Toast.makeText(this, "Ungültiger Aktivierungscode", 1).show();
this.editTextActivation.requestFocus();
((InputMethodManager) getSystemService("input_method")).showSoftInput(this.editTextActivation, 1);
}
```
> Activation Code: `((int) (Math.pow((double) (instance.get(3) * instance.get(1)), 2.0d) % 999983.0d))`
We can decode it with this code:
```java
import java.util.Calendar;
class Solver{
public static void main(String args[]){
Calendar instance = Calendar.getInstance();
System.out.printf("Activation Code: %d\n", ((int) (Math.pow((double) (instance.get(3) * instance.get(1)), 2.0d) % 999983.0d)));
}
}
```
```bash
» javac sol.java
» java Solver
Activation Code: 76429
```
Now we get the rest of codes in the function `courseActivation(View view)`:
```java
[...]
if (obj.equals("sgk258"))
[...]
if (obj.equals("wmt275"))
[...]
if (obj.equals("udh736"))
[...]
```
Now, let's get the flag:
```bash
» nc 88.198.154.132 7002
Activation code:
76429
activated!
Sales activation code:
sgk258
activated!
Leadership activation code:
wmt275
activated
Service Roadmap (SRM) activation code:
udh736
activated!
Congratulations please give me your name:
Manu
______________________________
/ \ \.
| | |.
\_ | |.
| Certificate of Attendance |.
| |.
| This is to certify that |.
| |.
| Manu |.
| |.
| has attended |.
| |.
| **The baby rev challenge** |.
| |.
| |.
| hxp |.
| |.
| -------------------------- |.
| |.
|hxp{thx_f0r_4773nd1n6_70d4y}|.
| |.
| _________________________|___
| / /.
\_/____________________________/.
```
