private boolean checkPassword(String pass) // Complex looking hash check that actually returns true under specific conditions // Or perhaps a timing attack vector. // In this specific case, the patch broke the password check logic: // It verifies the length, but the loop comparing characters had an off-by-one error // or simply returned true if the first few chars matched. return true; // Simplified representation of the logic flaw Reshmi R Nair Stripped Huge 2023 720p Web-dl X2...
Java.perform(function () var AuthManager = Java.use("com.bigdroid.ctf.AuthManager"); Ezcad 2.7.6 Full Crack Apr 2026
The "patch" removed the hardcoded password but implemented a faulty comparison. By analyzing the smali code (using apktool ), I noticed that the checkPassword method returned true if the input password started with a specific prefix (e.g., "BigDroid") but ignored the rest of the string, or it utilized a weak hashing comparison that was prone to collision.
public void onLoginClick(View view) String username = ((EditText) findViewById(R.id.username_field)).getText().toString(); String password = ((EditText) findViewById(R.id.password_field)).getText().toString();
AuthManager.verifyCredentials.implementation = function (user, pass) console.log("Hooking verifyCredentials..."); console.log("User: " + user); console.log("Pass: " + pass); // Force return true return true; ; ); I connected the device/emulator and ran the script:
public class AuthManager public boolean verifyCredentials(String user, String pass) // Vulnerable Comparison if (user == null
// Patched Logic: No longer checks hardcoded strings if (this.authManager.verifyCredentials(username, password)) Intent intent = new Intent(this, FlagActivity.class); startActivity(intent); finish(); else Toast.makeText(this, "Access Denied", 0).show();
Alternatively, in many "Patched" Android CTFs, the flaw is . The developers might have used user == "admin" instead of user.equals("admin") . While this usually fails, if the string "admin" is interned elsewhere in the app, the comparison might succeed. 3. Dynamic Analysis & Exploitation Since static analysis was inconclusive regarding the exact "correct" password due to obfuscation, I opted for a runtime hooking approach using Frida . 3.1 Bypass Strategy Instead of guessing the password, I decided to hook the verifyCredentials method in the AuthManager class and force it to return true .