CWE

Common Weakness Enumeration

A community-developed list of SW & HW weaknesses that can become vulnerabilities
New to CWE? click here!
CWE Most Important Hardware Weaknesses
CWE Top 25 Most Dangerous Weaknesses
Home > CWE List > CWE-306: Missing Authentication for Critical Function (4.17)  
ID

CWE-306: Missing Authentication for Critical Function

Weakness ID: 306
Vulnerability Mapping: ALLOWED This CWE ID may be used to map to real-world vulnerabilities
Abstraction: Base Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
View customized information:
For users who are interested in more notional aspects of a weakness. Example: educators, technical writers, and project/program managers. For users who are concerned with the practical application and details about the nature of a weakness and how to prevent it from happening. Example: tool developers, security researchers, pen-testers, incident response analysts. For users who are mapping an issue to CWE/CAPEC IDs, i.e., finding the most appropriate CWE for a specific issue (e.g., a CVE record). Example: tool developers, security researchers. For users who wish to see all available information for the CWE/CAPEC entry. For users who want to customize what details are displayed.
×

Edit Custom Filter


+ Description
The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources. Diagram for CWE-306
+ Common Consequences
Section HelpThis table specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.
Impact Details

Gain Privileges or Assume Identity; Varies by Context

Scope: Access Control, Other

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.
+ Potential Mitigations
Phase(s) Mitigation

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.

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.

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.

Architecture and Design

Strategy: Libraries or Frameworks

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].

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].
+ Relationships
Section Help This table shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.
+ Relevant to the view "Research Concepts" (View-1000)
Nature Type ID Name
ChildOf Class Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource. 287 Improper Authentication
ParentOf Base Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. 288 Authentication Bypass Using an Alternate Path or Channel
ParentOf Base Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource. 322 Key Exchange without Entity Authentication
+ Relevant to the view "Software Development" (View-699)
Nature Type ID Name
MemberOf Category Category - a CWE entry that contains a set of other entries that share a common characteristic. 1211 Authentication Errors
+ Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (View-1003)
Nature Type ID Name
ChildOf Class Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource. 287 Improper Authentication
+ Relevant to the view "Architectural Concepts" (View-1008)
Nature Type ID Name
MemberOf Category Category - a CWE entry that contains a set of other entries that share a common characteristic. 1010 Authenticate Actors
+ Modes Of Introduction
Section HelpThe different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.
Phase Note
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
Section HelpThis listing shows possible areas for which the given weakness could appear. These may be for specific named Languages, Operating Systems, Architectures, Paradigms, Technologies, or a class of such platforms. The platform is listed along with how frequently the given weakness appears for that instance.
Languages

Class: Not Language-Specific (Undetermined Prevalence)

Technologies

Class: Cloud Computing (Undetermined Prevalence)

Class: ICS/OT (Often Prevalent)

+ Likelihood Of Exploit
High
+ Demonstrative Examples

Example 1


In the following Java example the method createBankAccount is used to create a BankAccount object for a bank management application.

(bad code)
Example Language: Java 
public BankAccount createBankAccount(String accountNumber, String accountType,
String accountName, String accountSSN, double balance) {
BankAccount account = new BankAccount();
account.setAccountNumber(accountNumber);
account.setAccountType(accountType);
account.setAccountOwnerName(accountName);
account.setAccountOwnerSSN(accountSSN);
account.setBalance(balance);

return account;
}

However, there is no authentication mechanism to ensure that the user creating this bank account object has the authority to create new bank accounts. Some authentication mechanisms should be used to verify that the user has the authority to create bank account objects.

The following Java code includes a boolean variable and method for authenticating a user. If the user has not been authenticated then the createBankAccount will not create the bank account object.

(good code)
Example Language: Java 
private boolean isUserAuthentic = false;

// authenticate user,

// if user is authenticated then set variable to true

// otherwise set variable to false
public boolean authenticateUser(String username, String password) {
...
}

public BankAccount createNewBankAccount(String accountNumber, String accountType,
String accountName, String accountSSN, double balance) {
BankAccount account = null;

if (isUserAuthentic) {
account = new BankAccount();
account.setAccountNumber(accountNumber);
account.setAccountType(accountType);
account.setAccountOwnerName(accountName);
account.setAccountOwnerSSN(accountSSN);
account.setBalance(balance);
}
return account;
}


Example 2


In 2022, the OT:ICEFALL study examined products by 10 different Operational Technology (OT) vendors. The researchers reported 56 vulnerabilities and said that the products were "insecure by design" [REF-1283]. If exploited, these vulnerabilities often allowed adversaries to change how the products operated, ranging from denial of service to changing the code that the products executed. Since these products were often used in industries such as power, electrical, water, and others, there could even be safety implications.

Multiple vendors did not use any authentication for critical functionality in their OT products.



Example 3


In 2021, a web site operated by PeopleGIS stored data of US municipalities in Amazon Web Service (AWS) Simple Storage Service (S3) buckets.

(bad code)
Example Language: Other 
A security researcher found 86 S3 buckets that could be accessed without authentication (CWE-306) and stored data unencrypted (CWE-312). These buckets exposed over 1000 GB of data and 1.6 million files including physical addresses, phone numbers, tax documents, pictures of driver's license IDs, etc. [REF-1296] [REF-1295]

While it was not publicly disclosed how the data was protected after discovery, multiple options could have been considered.

(good code)
Example Language: Other 
The sensitive information could have been protected by ensuring that the buckets did not have public read access, e.g., by enabling the s3-account-level-public-access-blocks-periodic rule to Block Public Access. In addition, the data could have been encrypted at rest using the appropriate S3 settings, e.g., by enabling server-side encryption using the s3-bucket-server-side-encryption-enabled setting. Other settings are available to further prevent bucket data from being leaked. [REF-1297]


+ Selected Observed Examples

Note: this is a curated list of examples for users to understand the variety of ways in which this weakness can be introduced. It is not a complete list of all CVEs that are related to this CWE entry.

Reference Description
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.
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)
TCP-based protocol in Programmable Logic Controller (PLC) has no authentication.
Condition Monitor firmware uses a protocol that does not require authentication.
SCADA-based protocol for bridging WAN and LAN traffic has no authentication.
Safety Instrumented System uses proprietary TCP protocols with no authentication.
Distributed Control System (DCS) uses a protocol that has no authentication.
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.
Bluetooth speaker does not require authentication for the debug functionality on the UART port, allowing root shell access
WiFi router does not require authentication for its UART port, allowing adversaries with physical access to execute commands as root
IT management product does not perform authentication for some REST API requests, as exploited in the wild per CISA KEV.
Default setting in workflow management product allows all API requests without authentication, as exploited in the wild per CISA KEV.
MFV. Access TFTP server without authentication and obtain configuration file with sensitive plaintext information.
Agent software running at privileges does not authenticate incoming requests over an unprotected channel, allowing a Shatter" attack.
Product enforces restrictions through a GUI but not through privileged APIs.
monitor device allows access to physical UART debug port without authentication
Programmable Logic Controller (PLC) does not have an authentication feature on its communication protocols.
+ Detection Methods
Method Details

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.

Note:These may be more effective than strictly automated techniques. This is especially the case with weaknesses that are related to design and business rules.

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
+ Memberships
Section HelpThis MemberOf Relationships table shows additional CWE Categories and Views that reference this weakness as a member. This information is often useful in understanding where a weakness fits within the context of external information sources.
Nature Type ID Name
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 803 2010 Top 25 - Porous Defenses
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 812 OWASP Top Ten 2010 Category A3 - Broken Authentication and Session Management
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 866 2011 Top 25 - Porous Defenses
MemberOf ViewView - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries). 884 CWE Cross-section
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 952 SFP Secondary Cluster: Missing Authentication
MemberOf ViewView - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries). 1337 Weaknesses in the 2021 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf ViewView - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries). 1350 Weaknesses in the 2020 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1353 OWASP Top Ten 2021 Category A07:2021 - Identification and Authentication Failures
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1364 ICS Communications: Zone Boundary Failures
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1365 ICS Communications: Unreliability
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1366 ICS Communications: Frail Security in Protocols
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1368 ICS Dependencies (& Architecture): External Digital Systems
MemberOf ViewView - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries). 1387 Weaknesses in the 2022 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1396 Comprehensive Categorization: Access Control
MemberOf ViewView - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries). 1425 Weaknesses in the 2023 CWE Top 25 Most Dangerous Software Weaknesses
MemberOf ViewView - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries). 1430 Weaknesses in the 2024 CWE Top 25 Most Dangerous Software Weaknesses
+ Vulnerability Mapping Notes
Usage ALLOWED
(this CWE ID may be used to map to real-world vulnerabilities)
Reason Acceptable-Use

Rationale

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.

Comments

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.
+ Taxonomy Mappings
Mapped Taxonomy Name Node ID Fit Mapped Node Name
PLOVER No Authentication for Critical Function
Software Fault Patterns SFP31 Missing authentication
ISA/IEC 62443 Part 4-2 Req CR 1.1
ISA/IEC 62443 Part 4-2 Req CR 1.2
ISA/IEC 62443 Part 4-2 Req CR 2.1
ISA/IEC 62443 Part 4-1 Req SR-2
ISA/IEC 62443 Part 4-1 Req SVV-3
+ References
[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 2, "Common Vulnerabilities of Authentication," Page 36. 1st Edition. Addison Wesley. 2006.
[REF-257] Frank Kim. "Top 25 Series - Rank 19 - Missing Authentication for Critical Function". SANS Software Security Institute. 2010-02-23.
<https://www.sans.org/blog/top-25-series-rank-19-missing-authentication-for-critical-function/>. (URL validated: 2023-04-07)
[REF-45] OWASP. "OWASP Enterprise Security API (ESAPI) Project".
<http://www.owasp.org/index.php/ESAPI>.
[REF-1283] Forescout Vedere Labs. "OT:ICEFALL: The legacy of "insecure by design" and its implications for certifications and risk management". 2022-06-20.
<https://www.forescout.com/resources/ot-icefall-report/>.
[REF-1295] WizCase. "Over 80 US Municipalities' Sensitive Information, Including Resident's Personal Data, Left Vulnerable in Massive Data Breach". 2021-07-20.
<https://www.wizcase.com/blog/us-municipality-breach-report/>.
[REF-1296] Jonathan Greig. "1,000 GB of local government data exposed by Massachusetts software company". 2021-07-22.
<https://www.zdnet.com/article/1000-gb-of-local-government-data-exposed-by-massachusetts-software-company/>.
[REF-1297] Amazon. "AWS Foundational Security Best Practices controls". 2022.
<https://docs.aws.amazon.com/securityhub/latest/userguide/securityhub-controls-reference.html>. (URL validated: 2023-04-07)
[REF-1298] Microsoft. "Authentication and authorization in Azure App Service and Azure Functions". 2021-11-23.
<https://learn.microsoft.com/en-us/azure/app-service/overview-authentication-authorization>. (URL validated: 2022-10-11)
[REF-1302] Google Cloud. "Authentication and authorization use cases". 2022-10-11.
<https://cloud.google.com/docs/authentication/use-cases>. (URL validated: 2022-10-11)
+ Content History
+ Submissions
Submission Date Submitter Organization
2006-07-19
(CWE Draft 3, 2006-07-19) 		PLOVER
+ Contributions
Contribution Date Contributor Organization
2023-04-25 "Mapping CWE to 62443" Sub-Working Group CWE-CAPEC ICS/OT SIG
Suggested mappings to ISA/IEC 62443.
2024-02-29
(CWE 4.15, 2024-07-16) 		Abhi Balakrishnan
Provided diagram to improve CWE usability
+ Modifications
Modification Date Modifier Organization
2025-04-03
(CWE 4.17, 2025-04-03) 		CWE Content Team MITRE
updated Observed_Examples
2024-11-19
(CWE 4.16, 2024-11-19) 		CWE Content Team MITRE
updated Relationships
2024-07-16
(CWE 4.15, 2024-07-16) 		CWE Content Team MITRE
updated Common_Consequences, Description, Diagram, Modes_of_Introduction, Potential_Mitigations, Time_of_Introduction
2024-02-29
(CWE 4.14, 2024-02-29) 		CWE Content Team MITRE
updated Observed_Examples
2023-10-26 CWE Content Team MITRE
updated Observed_Examples
2023-06-29 CWE Content Team MITRE
updated Mapping_Notes, Relationships
2023-04-27 CWE Content Team MITRE
updated References, Relationships, Taxonomy_Mappings
2023-01-31 CWE Content Team MITRE
updated Related_Attack_Patterns, Relationships
2022-10-13 CWE Content Team MITRE
updated Applicable_Platforms, Demonstrative_Examples, Description, Observed_Examples, Potential_Mitigations, References, Relationship_Notes, Relationships
2022-06-28 CWE Content Team MITRE
updated Observed_Examples, Relationships
2021-10-28 CWE Content Team MITRE
updated Relationships
2021-07-20 CWE Content Team MITRE
updated Observed_Examples, Relationships
2020-08-20 CWE Content Team MITRE
updated Relationships
2020-02-24 CWE Content Team MITRE
updated Relationships
2019-06-20 CWE Content Team MITRE
updated Related_Attack_Patterns, Type
2019-01-03 CWE Content Team MITRE
updated Related_Attack_Patterns
2017-11-08 CWE Content Team MITRE
updated Likelihood_of_Exploit, Modes_of_Introduction, References, Relationships
2015-12-07 CWE Content Team MITRE
updated Relationships
2014-07-30 CWE Content Team MITRE
updated Detection_Factors, Relationships, Taxonomy_Mappings
2012-10-30 CWE Content Team MITRE
updated Potential_Mitigations
2012-05-11 CWE Content Team MITRE
updated Potential_Mitigations, Relationships
2011-09-13 CWE Content Team MITRE
updated Potential_Mitigations, References, Relationships
2011-06-27 CWE Content Team MITRE
updated Relationships
2011-06-01 CWE Content Team MITRE
updated Common_Consequences
2010-06-21 CWE Content Team MITRE
updated Common_Consequences, Potential_Mitigations, References
2010-02-16 CWE Content Team MITRE
updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Detection_Factors, Likelihood_of_Exploit, Name, Observed_Examples, Potential_Mitigations, References, Related_Attack_Patterns, Relationships
2008-09-08 CWE Content Team MITRE
updated Relationships, Relationship_Notes, Taxonomy_Mappings
2008-07-01 Eric Dalci Cigital
updated Time_of_Introduction
+ Previous Entry Names
Change Date Previous Entry Name
2010-02-16 No Authentication for Critical Function
Page Last Updated: April 03, 2025
 

Use of the Common Weakness Enumeration (CWE™) and the associated references from this website are subject to the Terms of Use. CWE is sponsored by the U.S. Department of Homeland Security (DHS) Cybersecurity and Infrastructure Security Agency (CISA) and managed by the Homeland Security Systems Engineering and Development Institute (HSSEDI) which is operated by The MITRE Corporation (MITRE). Copyright © 2006–2025, The MITRE Corporation. CWE, CWSS, CWRAF, and the CWE logo are trademarks of The MITRE Corporation.