CWE-784 Detail

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.

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.

Modes Of Introduction

Implementation

Applicable Platforms

Language

Class: Not Language-Specific (Undetermined)

Technologies

Class: Web Based (Often)

Common Consequences

Observed Examples

Potential Mitigations

Phases : Architecture and Design
Avoid using cookie data for a security-related decision.
Phases : 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.
Phases : Architecture and Design
Add integrity checks to detect tampering.
Phases : 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.

Vulnerability Mapping Notes

Justification : This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comment : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

NotesNotes

A new parent might need to be defined for this entry. This entry is specific to cookies, which reflects the significant number of vulnerabilities being reported for cookie-based authentication in CVE during 2008 and 2009. However, other types of inputs - such as parameters or headers - could also be used for similar authentication or authorization. Similar issues (under the Research view) include CWE-247 and CWE-472.

References

REF-706

Unforgivable Vulnerabilities
Steve Christey.
http://cve.mitre.org/docs/docs-2007/unforgivable.pdf

REF-7

Writing Secure Code
Michael Howard, David LeBlanc.
https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223

Submission

Modifications