CVE-2024-42475

In the OAuth library for nim prior to version 0.11, the state values generated by the generateState function do not have sufficient entropy. These can be successfully guessed by an attacker allowing them to perform a CSRF vs a user, associating the users session with the attackers protected resources. While state isnt exactly a cryptographic value, it should be generated in a cryptographically secure way. generateState should be using a CSPRNG. Version 0.11 modifies the generateState function to generate state values of at least 128 bits of entropy while using a CSPRNG.

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://github.com/CORDEA/oauth/blob/b8c163b0d9cfad6d29ce8c1fb394e5f47182ee1c/src/oauth2.nim#L179
• https://github.com/CORDEA/oauth/security/advisories/GHSA-332c-q46h-fg8f