Reliance on Cookies without Validation and Integrity Checking in a Security Decision

CWE-784

Per technology (GHSA, All time)

100%-RubyGems

Short description

The product uses a protection mechanism that relies on the existence or values of a cookie, but it does not properly ensure that the cookie is valid for the associated user.

Extended description

Attackers can easily modify cookies, within the browser or by implementing the client-side code outside of the browser. Attackers can bypass protection mechanisms such as authorization and authentication by modifying the cookie to contain an expected value.

Best practices to prevent this CWE

Phase: Architecture and Design

Avoid using cookie data for a security-related decision.

Phase: Implementation

Perform thorough input validation (i.e.: server side validation) on the cookie data if you're going to use it for a security related decision.

Phase: Architecture and Design

Add integrity checks to detect tampering.

Phase: Architecture and Design

Protect critical cookies from replay attacks, since cross-site scripting or other attacks may allow attackers to steal a strongly-encrypted cookie that also passes integrity checks. This mitigation applies to cookies that should only be valid during a single transaction or session. By enforcing timeouts, you may limit the scope of an attack. As part of your integrity check, use an unpredictable, server-side value that is not exposed to the client.

Recently published GHSA

GHSA-j6w9-fv6q-3q52

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