CWE-306 Detail

CWE-306

Missing Authentication for Critical Function
High
Draft
2006-07-19
00h00 +00:00
2025-04-03
00h00 +00:00
CWE Mitre.org
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Name: Missing Authentication for Critical Function

The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

General Informations

Modes Of Introduction

Architecture and Design : OMISSION: This weakness is caused by missing a security tactic during the architecture and design phase.
Architecture and Design : Developers sometimes perform authentication at the primary channel, but open up a secondary channel that is assumed to be private. For example, a login mechanism may be listening on one network port, but after successful authentication, it may open up a second port where it waits for the connection, but avoids authentication because it assumes that only the authenticated party will connect to the port.
Operation : When migrating data to the cloud (e.g., S3 buckets, Azure blobs, Google Cloud Storage, etc.), there is a risk of losing the protections that were originally provided by hosting on internal networks. If access does not require authentication, it can be easier for attackers to access the data from anywhere on the Internet.

Applicable Platforms

Language

Class: Not Language-Specific (Undetermined)

Technologies

Class: Cloud Computing (Undetermined)
Class: ICS/OT (Often)

Common Consequences

Scope Impact Likelihood
Access Control
Other		Gain Privileges or Assume Identity, Varies by Context

Note: Exposing critical functionality essentially provides an attacker with the privilege level of that functionality. The consequences will depend on the associated functionality, but they can range from reading or modifying sensitive data, accessing administrative or other privileged functionality, or possibly even executing arbitrary code.

Observed Examples

References Description

CVE-2024-11680

File-sharing PHP product does not check if user is logged in during requests for PHP library files under an includes/ directory, allowing configuration changes, code execution, and other impacts.

CVE-2022-31260

Chain: a digital asset management program has an undisclosed backdoor in the legacy version of a PHP script (CWE-912) that could allow an unauthenticated user to export metadata (CWE-306)

CVE-2022-29951

TCP-based protocol in Programmable Logic Controller (PLC) has no authentication.

CVE-2022-29952

Condition Monitor firmware uses a protocol that does not require authentication.

CVE-2022-30276

SCADA-based protocol for bridging WAN and LAN traffic has no authentication.

CVE-2022-30313

Safety Instrumented System uses proprietary TCP protocols with no authentication.

CVE-2022-30317

Distributed Control System (DCS) uses a protocol that has no authentication.

CVE-2021-21972

Chain: Cloud computing virtualization platform does not require authentication for upload of a tar format file (CWE-306), then uses .. path traversal sequences (CWE-23) in the file to access unexpected files, as exploited in the wild per CISA KEV.

CVE-2020-10263

Bluetooth speaker does not require authentication for the debug functionality on the UART port, allowing root shell access

CVE-2021-23147

WiFi router does not require authentication for its UART port, allowing adversaries with physical access to execute commands as root

CVE-2021-37415

IT management product does not perform authentication for some REST API requests, as exploited in the wild per CISA KEV.

CVE-2020-13927

Default setting in workflow management product allows all API requests without authentication, as exploited in the wild per CISA KEV.

CVE-2002-1810

MFV. Access TFTP server without authentication and obtain configuration file with sensitive plaintext information.

CVE-2008-6827

Agent software running at privileges does not authenticate incoming requests over an unprotected channel, allowing a Shatter" attack.

CVE-2004-0213

Product enforces restrictions through a GUI but not through privileged APIs.

CVE-2020-15483

monitor device allows access to physical UART debug port without authentication

CVE-2019-9201

Programmable Logic Controller (PLC) does not have an authentication feature on its communication protocols.

Potential Mitigations

Phases : Architecture and Design

Divide the software into anonymous, normal, privileged, and administrative areas. Identify which of these areas require a proven user identity, and use a centralized authentication capability.

Identify all potential communication channels, or other means of interaction with the software, to ensure that all channels are appropriately protected, including those channels that are assumed to be accessible only by authorized parties. Developers sometimes perform authentication at the primary channel, but open up a secondary channel that is assumed to be private. For example, a login mechanism may be listening on one network port, but after successful authentication, it may open up a second port where it waits for the connection, but avoids authentication because it assumes that only the authenticated party will connect to the port.

In general, if the software or protocol allows a single session or user state to persist across multiple connections or channels, authentication and appropriate credential management need to be used throughout.


Phases : Architecture and Design
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
Phases : Architecture and Design

Where possible, avoid implementing custom, "grow-your-own" authentication routines and consider using authentication capabilities as provided by the surrounding framework, operating system, or environment. These capabilities may avoid common weaknesses that are unique to authentication; support automatic auditing and tracking; and make it easier to provide a clear separation between authentication tasks and authorization tasks.

In environments such as the World Wide Web, the line between authentication and authorization is sometimes blurred. If custom authentication routines are required instead of those provided by the server, then these routines must be applied to every single page, since these pages could be requested directly.


Phases : Architecture and Design

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

For example, consider using libraries with authentication capabilities such as OpenSSL or the ESAPI Authenticator [REF-45].


Phases : Implementation // System Configuration // Operation
When storing data in the cloud (e.g., S3 buckets, Azure blobs, Google Cloud Storage, etc.), use the provider's controls to require strong authentication for users who should be allowed to access the data [REF-1297] [REF-1298] [REF-1302].

Detection Methods

Manual Analysis

This weakness can be detected using tools and techniques that require manual (human) analysis, such as penetration testing, threat modeling, and interactive tools that allow the tester to record and modify an active session.

Specifically, manual static analysis is useful for evaluating the correctness of custom authentication mechanisms.


Automated Static Analysis

Automated static analysis is useful for detecting commonly-used idioms for authentication. A tool may be able to analyze related configuration files, such as .htaccess in Apache web servers, or detect the usage of commonly-used authentication libraries.

Generally, automated static analysis tools have difficulty detecting custom authentication schemes. In addition, the software's design may include some functionality that is accessible to any user and does not require an established identity; an automated technique that detects the absence of authentication may report false positives.


Effectiveness : Limited

Manual Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:
  • Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Effectiveness : SOAR Partial

Dynamic Analysis with Automated Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:
  • Web Application Scanner
  • Web Services Scanner
  • Database Scanners

Effectiveness : SOAR Partial

Dynamic Analysis with Manual Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:
  • Host Application Interface Scanner
  • Fuzz Tester
  • Framework-based Fuzzer

Effectiveness : SOAR Partial

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:
  • Focused Manual Spotcheck - Focused manual analysis of source
  • Manual Source Code Review (not inspections)

Effectiveness : SOAR Partial

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:
  • Source code Weakness Analyzer
  • Context-configured Source Code Weakness Analyzer

Effectiveness : SOAR Partial

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:
  • Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)
  • Formal Methods / Correct-By-Construction
Cost effective for partial coverage:
  • Attack Modeling

Effectiveness : High

Vulnerability Mapping Notes

Justification : This CWE entry is at the Base 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.

Related Attack Patterns

CAPEC-ID Attack Pattern Name
CAPEC-12 Choosing Message Identifier
This pattern of attack is defined by the selection of messages distributed via multicast or public information channels that are intended for another client by determining the parameter value assigned to that client. This attack allows the adversary to gain access to potentially privileged information, and to possibly perpetrate other attacks through the distribution means by impersonation. If the channel/message being manipulated is an input rather than output mechanism for the system, (such as a command bus), this style of attack could be used to change the adversary's identifier to more a privileged one.
CAPEC-166 Force the System to Reset Values
An attacker forces the target into a previous state in order to leverage potential weaknesses in the target dependent upon a prior configuration or state-dependent factors. Even in cases where an attacker may not be able to directly control the configuration of the targeted application, they may be able to reset the configuration to a prior state since many applications implement reset functions.
CAPEC-216 Communication Channel Manipulation
An adversary manipulates a setting or parameter on communications channel in order to compromise its security. This can result in information exposure, insertion/removal of information from the communications stream, and/or potentially system compromise.
CAPEC-36 Using Unpublished Interfaces or Functionality
An adversary searches for and invokes interfaces or functionality that the target system designers did not intend to be publicly available. If interfaces fail to authenticate requests, the attacker may be able to invoke functionality they are not authorized for.
CAPEC-62 Cross Site Request Forgery
An attacker crafts malicious web links and distributes them (via web pages, email, etc.), typically in a targeted manner, hoping to induce users to click on the link and execute the malicious action against some third-party application. If successful, the action embedded in the malicious link will be processed and accepted by the targeted application with the users' privilege level. This type of attack leverages the persistence and implicit trust placed in user session cookies by many web applications today. In such an architecture, once the user authenticates to an application and a session cookie is created on the user's system, all following transactions for that session are authenticated using that cookie including potential actions initiated by an attacker and simply "riding" the existing session cookie.

References

REF-62

The Art of Software Security Assessment
Mark Dowd, John McDonald, Justin Schuh.

REF-257

Top 25 Series - Rank 19 - Missing Authentication for Critical Function
Frank Kim.
https://www.sans.org/blog/top-25-series-rank-19-missing-authentication-for-critical-function/

REF-45

OWASP Enterprise Security API (ESAPI) Project
OWASP.
http://www.owasp.org/index.php/ESAPI

REF-1283

OT:ICEFALL: The legacy of "insecure by design" and its implications for certifications and risk management
Forescout Vedere Labs.
https://www.forescout.com/resources/ot-icefall-report/

REF-1295

Over 80 US Municipalities' Sensitive Information, Including Resident's Personal Data, Left Vulnerable in Massive Data Breach
WizCase.
https://www.wizcase.com/blog/us-municipality-breach-report/

REF-1296

1,000 GB of local government data exposed by Massachusetts software company
Jonathan Greig.
https://www.zdnet.com/article/1000-gb-of-local-government-data-exposed-by-massachusetts-software-company/

REF-1297

AWS Foundational Security Best Practices controls
Amazon.
https://docs.aws.amazon.com/securityhub/latest/userguide/securityhub-controls-reference.html

REF-1298

Authentication and authorization in Azure App Service and Azure Functions
Microsoft.
https://learn.microsoft.com/en-us/azure/app-service/overview-authentication-authorization

REF-1302

Authentication and authorization use cases
Google Cloud.
https://cloud.google.com/docs/authentication/use-cases

Submission

Name Organization Date Date release Version
PLOVER 2006-07-19 +00:00 2006-07-19 +00:00 Draft 3

Modifications

Name Organization Date Comment
Eric Dalci Cigital 2008-07-01 +00:00 updated Time_of_Introduction
CWE Content Team MITRE 2008-09-08 +00:00 updated Relationships, Relationship_Notes, Taxonomy_Mappings
CWE Content Team MITRE 2010-02-16 +00:00 updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Detection_Factors, Likelihood_of_Exploit, Name, Observed_Examples, Potential_Mitigations, References, Related_Attack_Patterns, Relationships
CWE Content Team MITRE 2010-06-21 +00:00 updated Common_Consequences, Potential_Mitigations, References
CWE Content Team MITRE 2011-06-01 +00:00 updated Common_Consequences
CWE Content Team MITRE 2011-06-27 +00:00 updated Relationships
CWE Content Team MITRE 2011-09-13 +00:00 updated Potential_Mitigations, References, Relationships
CWE Content Team MITRE 2012-05-11 +00:00 updated Potential_Mitigations, Relationships
CWE Content Team MITRE 2012-10-30 +00:00 updated Potential_Mitigations
CWE Content Team MITRE 2014-07-30 +00:00 updated Detection_Factors, Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2015-12-07 +00:00 updated Relationships
CWE Content Team MITRE 2017-11-08 +00:00 updated Likelihood_of_Exploit, Modes_of_Introduction, References, Relationships
CWE Content Team MITRE 2019-01-03 +00:00 updated Related_Attack_Patterns
CWE Content Team MITRE 2019-06-20 +00:00 updated Related_Attack_Patterns, Type
CWE Content Team MITRE 2020-02-24 +00:00 updated Relationships
CWE Content Team MITRE 2020-08-20 +00:00 updated Relationships
CWE Content Team MITRE 2021-07-20 +00:00 updated Observed_Examples, Relationships
CWE Content Team MITRE 2021-10-28 +00:00 updated Relationships
CWE Content Team MITRE 2022-06-28 +00:00 updated Observed_Examples, Relationships
CWE Content Team MITRE 2022-10-13 +00:00 updated Applicable_Platforms, Demonstrative_Examples, Description, Observed_Examples, Potential_Mitigations, References, Relationship_Notes, Relationships
CWE Content Team MITRE 2023-01-31 +00:00 updated Related_Attack_Patterns, Relationships
CWE Content Team MITRE 2023-04-27 +00:00 updated References, Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2023-06-29 +00:00 updated Mapping_Notes, Relationships
CWE Content Team MITRE 2023-10-26 +00:00 updated Observed_Examples
CWE Content Team MITRE 2024-02-29 +00:00 updated Observed_Examples
CWE Content Team MITRE 2024-07-16 +00:00 updated Common_Consequences, Description, Diagram, Modes_of_Introduction, Potential_Mitigations, Time_of_Introduction
CWE Content Team MITRE 2024-11-19 +00:00 updated Relationships
CWE Content Team MITRE 2025-04-03 +00:00 updated Observed_Examples