Meesho Android App Improper Encryption Vulnerability Analysis (Weak MD5 Key/No Integrity Check)

Vulnerability Summary Vulnerability Overview The Meesho Android application (version 27.3) contains a severe Improper Encryption vulnerability. Specifically: 1. Weak Key Generation: The application uses the outdated MD5 hashing algorithm to generate encryption keys. The key derivation process lacks a salt and iterations, making the keys predictable and susceptible to brute-force or precomputation attacks. 2. Lack of Integrity Verification: The encrypted payload (consisting of a Base64-encoded IV and ciphertext) contains no integrity verification mechanism (such as HMAC or AES-GCM). 3. Consequences: Attackers can intercept and modify ciphertext in network traffic without detection, leading to unauthorized modification of sensitive request parameters. Furthermore, if the backend server returns different errors for encrypted responses, attackers may exploit "padding oracle attacks" to decrypt sensitive data or forge valid encrypted messages. Scope of Impact Affected Application: Meesho Android Application Affected Versions: 27.3 Remediation 1. Strengthen Key Derivation: Stop using MD5; instead, adopt more secure key derivation functions (e.g., PBKDF2, scrypt, Argon2) and introduce random salts and iteration counts. 2. Implement Integrity Checks: Use authenticated encryption modes (such as AES-GCM) or append a Message Authentication Code (HMAC) to the encrypted data to prevent ciphertext tampering. 3. Adhere to Security Standards: Follow the OWASP Mobile Top 10 (M5: Insufficient Cryptography) and MASVS guidelines (MSTG-CRYPTO-3 and MSTG-CRYPTO-4) for remediation. POC/Exploit Code The page does not directly contain specific code blocks but provides a link to a relevant GitHub repository which may contain exploit code:

Goal Reached Thanks to every supporter — we hit 100%!

Meesho Android App Improper Encryption Vulnerability Analysis (Weak MD5 Key/No Integrity Check)