CVE Vulnerabilities

CVE-2021-29480

Use of Insufficiently Random Values

Published: Jun 29, 2021 | Modified: Aug 02, 2022
CVSS 3.x
3.1
LOW
Source:
NVD
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N
CVSS 2.x
3.5 LOW
AV:N/AC:M/Au:S/C:N/I:P/A:N
RedHat/V2
RedHat/V3
Ubuntu

Ratpack is a toolkit for creating web applications. In versions prior to 1.9.0, the client side session module uses the application startup time as the signing key by default. This means that if an attacker can determine this time, and if encryption is not also used (which is recommended, but is not on by default), the session data could be tampered with by someone with the ability to write cookies. The default configuration is unsuitable for production use as an application restart renders all sessions invalid and is not multi-host compatible, but its use is not actively prevented. As of Ratpack 1.9.0, the default value is a securely randomly generated value, generated at application startup time. As a workaround, supply an alternative signing key, as per the documentations recommendation.

Weakness

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

Affected Software

Name Vendor Start Version End Version
Ratpack Ratpack_project * 1.9.0 (excluding)

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.

References