Authentication Bypass by Assumed-Immutable Data

The authentication scheme or implementation uses key data elements that are assumed to be immutable, but can be controlled or modified by the attacker.


Demonstrations

The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

In the following example, an "authenticated" cookie is used to determine whether or not a user should be granted access to a system.

boolean authenticated = new Boolean(getCookieValue("authenticated")).booleanValue();
if (authenticated) {
  ...
}

Of course, modifying the value of a cookie on the client-side is trivial, but many developers assume that cookies are essentially immutable.

See Also

Authenticate Actors

Weaknesses in this category are related to the design and architecture of authentication components of the system. Frequently these deal with verifying the entity is i...

SFP Secondary Cluster: Faulty Endpoint Authentication

This category identifies Software Fault Patterns (SFPs) within the Faulty Endpoint Authentication cluster (SFP29).

Comprehensive CWE Dictionary

This view (slice) covers all the elements in CWE.

Weaknesses without Software Fault Patterns

CWE identifiers in this view are weaknesses that do not have associated Software Fault Patterns (SFPs), as covered by the CWE-888 view. As such, they represent gaps in...

Weaknesses Introduced During Implementation

This view (slice) lists weaknesses that can be introduced during implementation.


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