Weak Cryptographic Algorithms (MD5/SHA1/DES/RC4/ECB)

← Insufficient Cryptography

weak_algorithms   EASY

Description

MD5/SHA1 for password hashing and DES/RC4/AES-ECB for encryption.

How it works

Passwords are hashed with fast, unsalted MD5/SHA-1, which are friendly to rainbow-table lookups and brute forcing, and data is encrypted with AES in ECB mode using a hardcoded key. ECB leaks plaintext structure because identical plaintext blocks produce identical ciphertext blocks.

How to exercise it. DVMA is the harness - open this module from the home index and tap the demo action. The screen ships the malicious input and simulates the attacker (e.g. the companion app, crafted intent, or scanned payload) in-process, and the evidence panel prints the proof. The Tools (optional) and Attack inputs below are only needed to reproduce the exploit end-to-end on a real device.

Exploit steps

1. Set up. Build DVMA with a flavor that enables the Insufficient Cryptography category (e.g. --dart-define-from-file=config/flavors/dev.json) and run on an emulator/simulator you control. The demo needs no external tooling; for the optional on-device reproduction the relevant tools are: frida, frida-trace, r2, MobSF · Android: jadx, apktool · iOS: ipsw, Hopper, Ghidra, r2ghidra, class-dump.
2. Locate the target. From the home index, open Weak Cryptographic Algorithms (MD5/SHA1/DES/RC4/ECB) (weak_algorithms). The How it works section above describes this module’s specific weakness; the screen states the intended-secure behavior and exposes the vulnerable action.
3. Exploit. Capture the algorithm/key/IV the module uses (the evidence panel prints it), then reproduce the weakness offline - e.g. recompute the digest, brute the short key, or decrypt a captured blob - to show the protection is ineffective.
4. Observe the evidence. Trigger the vulnerable action and read the evidence panel - it prints the concrete proof (leaked value, accepted replay, executed payload, or unauthorized result).
5. Contrast with the secure path. Run the module’s secure/hardened action (where provided) and confirm the same attack is rejected - this is what a correct implementation should do.
6. Map it back. Cross-reference the MASTG v2 test(s) MASTG-TEST-0210, MASTG-TEST-0221, MASTG-TEST-0232, MASTG-TEST-0317, MASTG-TEST-0211 for the canonical procedure and remediation.

Tools (optional)

• frida
• frida-trace
• r2
• MobSF

Android

• jadx
• apktool

iOS

• ipsw
• Hopper
• Ghidra
• r2ghidra
• class-dump