CWE - CWE-293: Using Referer Field for Authentication (4.19.1)
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    CWE-293: Using Referer Field for Authentication

    Weakness ID: 293
    Vulnerability Mapping: ALLOWED This CWE ID may be used to map to real-world vulnerabilities
    Abstraction: Variant Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.
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    + Description
    The referer field in HTTP requests can be easily modified and, as such, is not a valid means of message integrity checking.
    + Alternate Terms
    referrer
    While the proper spelling might be regarded as "referrer," the HTTP RFCs and their implementations use "referer," so this is regarded as the correct spelling.
    + 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

    		Scope: Access Control

    Actions, which may not be authorized otherwise, can be carried out as if they were validated by the server referred to.
    + Potential Mitigations
    Phase(s) Mitigation

    Architecture and Design
    In order to usefully check if a given action is authorized, some means of strong authentication and method protection must be used. Use other means of authorization that cannot be simply spoofed. Possibilities include a username/password or certificate.
    + 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 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. 290 Authentication Bypass by Spoofing
    + 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
    + Background Details
    The referer field in HTML requests can be simply modified by malicious users, rendering it useless as a means of checking the validity of the request in question.
    + 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 COMMISSION: This weakness refers to an incorrect design related to an architectural security tactic.
    + 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)

    + Likelihood Of Exploit
    High
    + Demonstrative Examples

    Example 1


    The following code samples check a packet's referer in order to decide whether or not an inbound request is from a trusted host.

    (bad code)
    Example Language: C++ 
    String trustedReferer = "http://www.example.com/"
    while(true){
    n = read(newsock, buffer, BUFSIZE);
    requestPacket = processPacket(buffer, n);
    if (requestPacket.referer == trustedReferer){
    openNewSecureSession(requestPacket);
    }
    }
    (bad code)
    Example Language: Java 
    boolean processConnectionRequest(HttpServletRequest request){
    String referer = request.getHeader("referer")
    String trustedReferer = "http://www.example.com/"
    if(referer.equals(trustedReferer)){
    openPrivilegedConnection(request);
    return true;
    }
    else{
    sendPrivilegeError(request);
    return false;
    }
    }

    These examples check if a request is from a trusted referer before responding to a request, but the code only verifies the referer name as stored in the request packet. An attacker can spoof the referer, thus impersonating a trusted client.



    + Weakness Ordinalities
    Ordinality Description
    Primary
    (where the weakness exists independent of other weaknesses)
    + Detection Methods
    Method Details

    Automated Static Analysis
    Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

    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. 949 SFP Secondary Cluster: Faulty Endpoint Authentication
    MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1396 Comprehensive Categorization: Access Control
    MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1442 OWASP Top Ten 2025 Category A07:2025 - Authentication Failures
    + 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 Variant 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
    CLASP Using referrer field for authentication
    Software Fault Patterns SFP29 Faulty endpoint authentication
    + References
    [REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 17, "Referer Request Header", Page 1030. 1st Edition. Addison Wesley. 2006.
    [REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005.
    <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>. (URL validated: 2024-11-17)
    + Content History
    + Submissions
    Submission Date Submitter Organization
    2006-07-19
    (CWE Draft 3, 2006-07-19)     		CLASP
    + Modifications
    Modification Date Modifier Organization
    2025-12-11
    (CWE 4.19, 2025-12-11)     		CWE Content Team MITRE
    updated Relationships, Weakness_Ordinalities
    2023-06-29 CWE Content Team MITRE
    updated Mapping_Notes
    2023-04-27 CWE Content Team MITRE
    updated Detection_Factors, Relationships
    2021-03-15 CWE Content Team MITRE
    updated References
    2020-02-24 CWE Content Team MITRE
    updated Relationships
    2017-11-08 CWE Content Team MITRE
    updated Applicable_Platforms, Modes_of_Introduction, Relationships, Relevant_Properties
    2014-07-30 CWE Content Team MITRE
    updated Relationships, Taxonomy_Mappings
    2012-10-30 CWE Content Team MITRE
    updated Demonstrative_Examples
    2012-05-11 CWE Content Team MITRE
    updated Common_Consequences, Demonstrative_Examples, References, Relationships
    2011-06-01 CWE Content Team MITRE
    updated Common_Consequences
    2008-09-08 CWE Content Team MITRE
    updated Alternate_Terms, Background_Details, Common_Consequences, Relationships, Relevant_Properties, Taxonomy_Mappings
    Page Last Updated: January 21, 2026