CWE-336: Same Seed in Pseudo-Random Number Generator (PRNG)
A Pseudo-Random Number Generator (PRNG) uses the same seed each time the product is initialized.
How it's found
Same Seed in Pseudo-Random Number Generator (PRNG) is a specific, narrowly defined instance of a broader pattern. Testers confirm it with targeted code review and a proof-of-concept input that exercises the exact code path this weakness describes.
Given the deterministic nature of PRNGs, using the same seed for each initialization will lead to the same output in the same order. If an attacker can guess (or knows) the seed, then the attacker may be able to determine the random numbers that will be produced from the PRNG.
Consequences
- Other, Bypass Protection Mechanism
Mitigations
- Architecture and Design: Do not reuse PRNG seeds. Consider a PRNG that periodically re-seeds itself as needed from a high quality pseudo-random output, such as hardware devices.
- Architecture and Design/Requirements: Use products or modules that conform to FIPS 140-2 [REF-267] to avoid obvious entropy problems, or use the more recent FIPS 140-3 [REF-1192] if possible.
Where this fits in a TurboPentest engagement
TurboPentest's agentic pentest is powerful and covers a broad range of issues automatically. This particular class is best confirmed in a manual IntegSec engagement, where human pentesters apply deeper methodology and a larger context window than any automated pass.
Frequently asked questions
What is CWE-336?
A Pseudo-Random Number Generator (PRNG) uses the same seed each time the product is initialized.
How do you find Same Seed in Pseudo-Random Number Generator (PRNG)?
Same Seed in Pseudo-Random Number Generator (PRNG) is a specific, narrowly defined instance of a broader pattern. Testers confirm it with targeted code review and a proof-of-concept input that exercises the exact code path this weakness describes.
What is the impact of CWE-336?
Other, Bypass Protection Mechanism
Does TurboPentest test for Same Seed in Pseudo-Random Number Generator (PRNG)?
TurboPentest's agentic pentest is powerful and covers a broad range of issues automatically. This particular class is best confirmed in a manual IntegSec engagement, where human pentesters apply deeper methodology and a larger context window than any automated pass.
Related CWEs
About this reference
These security references are maintained by IntegSec, an offensive-security firm whose team holds CISSP, OSCP, and OSCE certifications and has run thousands of penetration tests. Content is kept current as tools, standards, and attack techniques evolve.
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