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CWE-1385: Missing Origin Validation in WebSockets

Weakness ID: 1385
Abstraction: Variant
Structure: Simple
Presentation Filter:
+ Description
The software uses a WebSocket, but it does not properly verify that the source of data or communication is valid.
+ Extended Description

WebSockets provide a bi-directional low latency communication (near real-time) between a client and a server. WebSockets are different than HTTP in that the connections are long-lived, as the channel will remain open until the client or the server is ready to send the message, whereas in HTTP, once the response occurs (which typically happens immediately), the transaction completes.

A WebSocket can leverage the existing HTTP protocol over ports 80 and 443, but it is not limited to HTTP. WebSockets can make cross-origin requests that are not restricted by browser-based protection mechanisms such as the Same Origin Policy (SOP) or Cross-Origin Resource Sharing (CORS). Without explicit origin validation, this makes CSRF attacks more powerful.

+ Alternate Terms
Cross-Site WebSocket hijacking (CSWSH):
this term is used for attacks that exploit this weakness
+ Relationships
Section HelpThis 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" (CWE-1000)
ChildOfBaseBase - 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.346Origin Validation Error
+ 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.
Architecture and Design
+ 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.


Class: Language-Independent (Undetermined Prevalence)


Web Server (Undetermined Prevalence)

+ 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.
Access Control

Technical Impact: Varies by Context; Gain Privileges or Assume Identity; Bypass Protection Mechanism; Read Application Data; Modify Application Data; DoS: Crash, Exit, or Restart

The consequences will vary depending on the nature of the functionality that is vulnerable to CSRF. An attacker could effectively perform any operations as the victim. If the victim is an administrator or privileged user, the consequences may include obtaining complete control over the web application - deleting or stealing data, uninstalling the product, or using it to launch other attacks against all of the product's users. Because the attacker has the identity of the victim, the scope of the CSRF is limited only by the victim's privileges.
+ Observed Examples
web console for SIEM product does not check Origin header, allowing Cross Site WebSocket Hijacking (CSWH)
Chain: gaming client attempts to validate the Origin header, but only uses a substring, allowing Cross-Site WebSocket hijacking by forcing requests from an origin whose hostname is a substring of the valid origin.
WebSocket server does not check the origin of requests, allowing attackers to steal developer's code using a ws:// connection.
WebSocket server does not check the origin of requests, allowing attackers to steal developer's code using a ws:// connection to a randomized port number.
WebSocket server does not check the origin of requests, allowing attackers to steal developer's code using a ws:// connection.
+ Potential Mitigations

Phase: Implementation

Enable CORS-like access restrictions by verifying the 'Origin' header during the WebSocket handshake.

Phase: Implementation

Use a randomized CSRF token to verify requests.

Phase: Implementation

Use TLS to securely communicate using 'wss' (WebSocket Secure) instead of 'ws'.

Phases: Architecture and Design; Implementation

Require user authentication prior to the WebSocket connection being established. For example, the WS library in Node has a 'verifyClient' function.

Phase: Implementation

Leverage rate limiting to prevent against DoS. Use of the leaky bucket algorithm can help with this.

Effectiveness: Defense in Depth

Phase: Implementation

Use a library that provides restriction of the payload size. For example, WS library for Node includes 'maxPayloadoption' that can be set.

Effectiveness: Defense in Depth

Phase: Implementation

Treat data/input as untrusted in both directions and apply the same data/input sanitization as XSS, SQLi, etc.
+ References
[REF-1257] Christian Schneider. "Cross-Site WebSocket Hijacking (CSWSH)". 2013-09-01. <>.
[REF-1251] Drew Branch. "WebSockets not Bound by SOP and CORS? Does this mean…". 2018-06-06. <>.
[REF-1252] Mehul Mohan. "How to secure your WebSocket connections". 2018-11-12. <>.
[REF-1256] Vickie Li. "Cross-Site WebSocket Hijacking (CSWSH)". 2019-11-27. <>.
[REF-1253] PortSwigger. "Testing for WebSockets security vulnerabilities". Using cross-site WebSockets to exploit vulnerabilities. <>.
+ Content History
+ Submissions
Submission DateSubmitterOrganization
2021-05-28Anonymous External Contributor
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Page Last Updated: May 05, 2022