OwaspCryptographicFailures [principle] v1.0.0

OWASP Top 10 A02:2021 (formerly Sensitive Data Exposure) — failures related to cryptography or lack thereof that lead to exposure of sensitive data or system compromise.

Sensitive data must be encrypted in transit (TLS 1.2+) and at rest (AES-256 or ChaCha20-Poly1305). Passwords must use dedicated slow hash functions (bcrypt/Argon2id/scrypt). Deprecated algorithms (MD5, SHA-1, DES, RC4, ECB mode) must never appear in new code regardless of context.

Attributed To

OWASP Foundation, Top 10 2021

Applies To

• User password storage
• PII data (SSN, credit card, health records) at rest
• Data transmitted over any network (internal or external)
• Session tokens, API keys, and secrets in storage
• Cryptographic key management and rotation
• TLS certificate configuration and cipher suite selection

Counter Examples

• Adobe 2013 breach: 153M passwords stored as reversible encrypted (3DES ECB) with a shared key — decryptable, not hashed; patterns visible from duplicate ciphertexts.
• LinkedIn 2012 breach: 117M passwords hashed with unsalted SHA-1 — rainbow tables cracked ~90% within days of the dump being published.
• Storing credit card PANs in a VARCHAR column with application-layer AES-ECB encryption — ECB mode preserves plaintext patterns; violates PCI-DSS.

OwaspCryptographicFailures [principle] v1.0.0

OWASP Top 10 A02:2021 (formerly Sensitive Data Exposure) — failures related to cryptography or lack thereof that lead to exposure of sensitive data or system compromise.

Sensitive data must be encrypted in transit (TLS 1.2+) and at rest (AES-256 or ChaCha20-Poly1305). Passwords must use dedicated slow hash functions (bcrypt/Argon2id/scrypt). Deprecated algorithms (MD5, SHA-1, DES, RC4, ECB mode) must never appear in new code regardless of context.

Attributed To

OWASP Foundation, Top 10 2021

Applies To

• User password storage
• PII data (SSN, credit card, health records) at rest
• Data transmitted over any network (internal or external)
• Session tokens, API keys, and secrets in storage
• Cryptographic key management and rotation
• TLS certificate configuration and cipher suite selection

Counter Examples

• Adobe 2013 breach: 153M passwords stored as reversible encrypted (3DES ECB) with a shared key — decryptable, not hashed; patterns visible from duplicate ciphertexts.
• LinkedIn 2012 breach: 117M passwords hashed with unsalted SHA-1 — rainbow tables cracked ~90% within days of the dump being published.
• Storing credit card PANs in a VARCHAR column with application-layer AES-ECB encryption — ECB mode preserves plaintext patterns; violates PCI-DSS.

Sources

Examples

• Signal Protocol: uses Curve25519, AES-256-CBC, and HMAC-SHA256 — published algorithm choices, audited implementations, forward secrecy via Diffie-Hellman ratchet.
• Let's Encrypt: automated TLS certificate issuance and renewal removes human error from certificate management — forces HTTPS by default.
• AWS KMS: envelope encryption pattern — data encrypted with data key, data key encrypted with CMK — key material never leaves HSM boundary.
• 1Password: PBKDF2 with 100,000 iterations + SRP (Secure Remote Password) — master password never transmitted, server never holds plaintext.

Source

• https://owasp.org/Top10/A02_2021-Cryptographic_Failures/
• NIST SP 800-175B: Guideline for Using Cryptographic Standards in the Federal Government
• CVE-2012-5958 through CVE-2012-5964: UPnP implementations using homegrown crypto — 50M+ devices affected.