CWE-306: Missing Authentication for Critical Function
Weakness ID: 306
Vulnerability Mapping:ALLOWEDThis CWE ID may be used to map to real-world vulnerabilities Abstraction:
BaseBase - 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.
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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 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
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.
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.
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.
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.
The 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
This 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.
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) {
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.
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)
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.
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:
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.
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).
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).
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).
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).
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).
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).
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.
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.
Description
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.
