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CWE Glossary Definition
CWE-306: Missing Authentication for Critical Function
Weakness ID: 306Vulnerability 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.×
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Description
The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources. 
Common Consequences
This 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 MitigationsPhase(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
Relationships
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 - 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 - 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 - 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 - 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 - 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 - a CWE entry that contains a set of other entries that share a common characteristic.
1010 Authenticate Actors
Modes
Of IntroductionThe 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 PlatformsThis 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 ExamplesExample 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: Javapublic 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: Javaprivate 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: OtherA 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: OtherThe 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
ExamplesNote: 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.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.Bluetooth speaker does not require authentication for the debug functionality on the UART port, allowing root shell accessWiFi router does not require authentication for its UART port, allowing adversaries with physical access to execute commands as rootIT 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 authenticationProgrammable Logic Controller (PLC) does not have an authentication feature on its communication protocols. Detection
MethodsMethod Details Manual Analysis
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.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 [REF-1479], 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 [REF-1479], 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 [REF-1479], 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 [REF-1479], 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 [REF-1479], 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 [REF-1479], 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
This 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 Category - a CWE entry that contains a set of other entries that share a common characteristic.803 2010 Top 25 - Porous Defenses MemberOf Category - 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 Category - a CWE entry that contains a set of other entries that share a common characteristic.866 2011 Top 25 - Porous Defenses MemberOf 
View - 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 Category - a CWE entry that contains a set of other entries that share a common characteristic.952 SFP Secondary Cluster: Missing Authentication MemberOf View - 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 View - 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 Category - 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 Category - a CWE entry that contains a set of other entries that share a common characteristic.1364 ICS Communications: Zone Boundary Failures MemberOf Category - a CWE entry that contains a set of other entries that share a common characteristic.1365 ICS Communications: Unreliability MemberOf Category - a CWE entry that contains a set of other entries that share a common characteristic.1366 ICS Communications: Frail Security in Protocols MemberOf Category - a CWE entry that contains a set of other entries that share a common characteristic.1368 ICS Dependencies (& Architecture): External Digital Systems MemberOf View - 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 Category - a CWE entry that contains a set of other entries that share a common characteristic.1396 Comprehensive Categorization: Access Control MemberOf View - 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 View - 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 NotesUsage 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
MappingsMapped 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
Related Attack Patterns 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: 2025-07-29)[REF-45] OWASP. "OWASP Enterprise Security API (ESAPI) Project".
<https://owasp.org/www-project-enterprise-security-api/>. (URL validated: 2025-07-24)[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)[REF-1479] Gregory Larsen, E. Kenneth Hong Fong, David A. Wheeler and Rama S. Moorthy. "State-of-the-Art Resources (SOAR) for Software Vulnerability Detection, Test, and Evaluation". 2014-07.
<https://www.ida.org/-/media/feature/publications/s/st/stateoftheart-resources-soar-for-software-vulnerability-detection-test-and-evaluation/p-5061.ashx>. (URL validated: 2025-09-05) Content
History SubmissionsSubmission Date Submitter Organization 2006-07-19
(CWE Draft 3, 2006-07-19)PLOVER ContributionsContribution 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 
ModificationsModification Date Modifier Organization 2025-09-09
(CWE 4.18, 2025-09-09)CWE Content Team MITRE updated Detection_Factors, References 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 NamesChange Date Previous Entry Name 2010-02-16 No Authentication for Critical Function More information is available — Please edit the custom filter or select a different filter.Page Last Updated: September 09, 2025
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