CVE-2024-21495

Versions of the package github.com/greenpau/caddy-security before 1.0.42 are vulnerable to Insecure Randomness due to using an insecure random number generation library which could possibly be predicted via a brute-force search. Attackers could use the potentially predictable nonce value used for authentication purposes in the OAuth flow to conduct OAuth replay attacks. In addition, insecure randomness is used while generating multifactor authentication (MFA) secrets and creating API keys in the database package.

Weakness

The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.

Potential Mitigations

• Use a well-vetted algorithm that is currently considered to be strong by experts in the field, and select well-tested implementations with adequate length seeds.
• In general, if a pseudo-random number generator is not advertised as being cryptographically secure, then it is probably a statistical PRNG and should not be used in security-sensitive contexts.
• Pseudo-random number generators can produce predictable numbers if the generator is known and the seed can be guessed. A 256-bit seed is a good starting point for producing a “random enough” number.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/112.html
• https://cwe.mitre.org/data/definitions/485.html
• https://cwe.mitre.org/data/definitions/59.html

References

• https://blog.trailofbits.com/2023/09/18/security-flaws-in-an-sso-plugin-for-caddy/
• https://github.com/greenpau/caddy-security/issues/265
• https://github.com/greenpau/go-authcrunch/commit/ecd3725baf2683eb1519bb3c81ae41085fbf7dc2
• https://security.snyk.io/vuln/SNYK-GOLANG-GITHUBCOMGREENPAUCADDYSECURITY-6248275