CWE-302

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.

Mitigation

Phases: Architecture and Design, Operation, Implementation

Description:

  • Implement proper protection for immutable data (e.g. environment variable, hidden form fields, etc.)
CAPEC-10: Buffer Overflow via Environment Variables

This attack pattern involves causing a buffer overflow through manipulation of environment variables. Once the adversary finds that they can modify an environment variable, they may try to overflow associated buffers. This attack leverages implicit trust often placed in environment variables.

CAPEC-13: Subverting Environment Variable Values

The adversary directly or indirectly modifies environment variables used by or controlling the target software. The adversary's goal is to cause the target software to deviate from its expected operation in a manner that benefits the adversary.

CAPEC-21: Exploitation of Trusted Identifiers

An adversary guesses, obtains, or "rides" a trusted identifier (e.g. session ID, resource ID, cookie, etc.) to perform authorized actions under the guise of an authenticated user or service.

CAPEC-274: HTTP Verb Tampering

An attacker modifies the HTTP Verb (e.g. GET, PUT, TRACE, etc.) in order to bypass access restrictions. Some web environments allow administrators to restrict access based on the HTTP Verb used with requests. However, attackers can often provide a different HTTP Verb, or even provide a random string as a verb in order to bypass these protections. This allows the attacker to access data that should otherwise be protected.

CAPEC-31: Accessing/Intercepting/Modifying HTTP Cookies

This attack relies on the use of HTTP Cookies to store credentials, state information and other critical data on client systems. There are several different forms of this attack. The first form of this attack involves accessing HTTP Cookies to mine for potentially sensitive data contained therein. The second form involves intercepting this data as it is transmitted from client to server. This intercepted information is then used by the adversary to impersonate the remote user/session. The third form is when the cookie's content is modified by the adversary before it is sent back to the server. Here the adversary seeks to convince the target server to operate on this falsified information.

CAPEC-39: Manipulating Opaque Client-based Data Tokens

In circumstances where an application holds important data client-side in tokens (cookies, URLs, data files, and so forth) that data can be manipulated. If client or server-side application components reinterpret that data as authentication tokens or data (such as store item pricing or wallet information) then even opaquely manipulating that data may bear fruit for an Attacker. In this pattern an attacker undermines the assumption that client side tokens have been adequately protected from tampering through use of encryption or obfuscation.

CAPEC-45: Buffer Overflow via Symbolic Links

This type of attack leverages the use of symbolic links to cause buffer overflows. An adversary can try to create or manipulate a symbolic link file such that its contents result in out of bounds data. When the target software processes the symbolic link file, it could potentially overflow internal buffers with insufficient bounds checking.

CAPEC-77: Manipulating User-Controlled Variables

This attack targets user controlled variables (DEBUG=1, PHP Globals, and So Forth). An adversary can override variables leveraging user-supplied, untrusted query variables directly used on the application server without any data sanitization. In extreme cases, the adversary can change variables controlling the business logic of the application. For instance, in languages like PHP, a number of poorly set default configurations may allow the user to override variables.

Back to CWE stats page