Weakness · High
CWE-323: Reusing a Nonce, Key Pair in Encryption
What it is
Nonces should be used for the present occasion and only once.
- Severity (our rating)
- High
- Likelihood of exploit
- High
- Introduced during
- Architecture and Design
- Exploited in the wild
- No CVE in CISA's catalog
What an attacker can do
- Bypass Protection Mechanism (Access Control)
- Gain Privileges or Assume Identity (Access Control)
How to prevent it
Implementation
- Refuse to reuse nonce values.
- Use techniques such as requiring incrementing, time based and/or challenge response to assure uniqueness of nonces.
How to find it
- Automated Static Analysis. Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
H2 Security
Found it in your code?
We review where it appears, fix it with your team, and check it was not already used against you.
Talk to our teamT Academy
Stop writing it in the first place
Learn to build software and systems without weaknesses like this one, with practice on real hosts in your browser, every objective checked on the machine.
Start freeSource: MITRE Common Weakness Enumeration, CWE version 4.19.1. CWE is a trademark of The MITRE Corporation.