CWE-337: Predictable Seed in Pseudo-Random Number Generator (PRNG)
Description
A Pseudo-Random Number Generator (PRNG) is initialized from a predictable seed, such as the process ID or system time.
The use of predictable seeds significantly reduces the number of possible seeds that an attacker would need to test in order to predict which random numbers will be generated by the PRNG.
- Abstraction
- VariantA weakness tied to a specific language, technology or resource.
- Likelihood of exploit
- Not rated by MITRE
- Status
- Draft
Common consequences
- Other
Varies by Context
Potential mitigations
Use non-predictable inputs for seed generation.
- Architecture and DesignRequirementsLibraries or Frameworks
Use products or modules that conform to FIPS 140-2 to avoid obvious entropy problems, or use the more recent FIPS 140-3 if possible.
- Implementation
Use a PRNG that periodically re-seeds itself using input from high-quality sources, such as hardware devices with high entropy. However, do not re-seed too frequently, or else the entropy source might block.
Related weaknesses
CAPEC attack patterns that exploit it
CWE 4.20 links no CAPEC attack pattern to this weakness.