CWE-1204 — Generation of Weak Initialization Vector (IV)
CWE-1204: Generation of Weak Initialization Vector (IV)
MITRE CWE weakness
| Kind | Weakness |
| Abstraction | Base |
| Status | Incomplete |
| Likelihood of exploit | — |
Description
The product uses a cryptographic primitive that uses an Initialization Vector (IV), but the product does not generate IVs that are sufficiently unpredictable or unique according to the expected cryptographic requirements for that primitive.
By design, some cryptographic primitives (such as block ciphers) require that IVs must have certain properties for the uniqueness and/or unpredictability of an IV. Primitives may vary in how important these properties are. If these properties are not maintained, e.g. by a bug in the code, then the cryptography may be weakened or broken by attacking the IVs themselves.
Common consequences
- Confidentiality: Read Application Data
Mitigations
Implementation — Different cipher modes have different requirements for their IVs. When choosing and implementing a mode, it is important to understand those requirements in order to keep security guarantees intact. Generally, it is safest to generate a random IV, since it will be both unpredictable and have a very low chance of being non-unique. IVs do not have to be kept secret, so if generating duplicate IVs is a concern, a list of already-used IVs can be kept and checked against. NIST offers recommendations on generation of IVs for modes of which they have approved. These include options for when random IVs are not practical. For CBC, CFB, and OFB, see [REF-1175]; for GCM, see [REF-1178].
References
- CWE page: https://cwe.mitre.org/data/definitions/1204.html
- CWE list: https://cwe.mitre.org/data/index.html