CAPEC-22
Exploiting Trust in Client
An attack of this type exploits vulnerabilities in client/server communication channel authentication and data integrity. It leverages the implicit trust a server places in the client, or more importantly, that which the server believes is the client. An attacker executes this type of attack by communicating directly with the server where the server believes it is communicating only with a valid client. There are numerous variations of this type of attack.
On this page
Ask an AI about this attack pattern
Show the prompt
Explain the attack pattern CAPEC-22: Exploiting Trust in Client: how it unfolds, what it needs and how to prevent and detect it in my systems. Use https://capec.mitre.org/data/definitions/22.html and https://cve.bz/cve/capec/22?via=ask-ai-copy, which lists recent CVEs with the weaknesses it exploits. Cite the sources.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this attack pattern's id and public links.
Prerequisites
Server software must rely on client side formatted and validated values, and not reinforce these checks on the server side.
Skills required
- Medium skill
The attacker must have fairly detailed knowledge of the syntax and semantics of client/server communications protocols and grammars
Resources required
Ability to communicate synchronously or asynchronously with server
Consequences
| Impact | Affects | Note |
|---|---|---|
| Execute Unauthorized Commands | Confidentiality, Integrity, Availability | Run Arbitrary Code |
| Gain Privileges | Confidentiality, Access Control, Authorization | |
| Read Data | Confidentiality |
Mitigations
Design: Ensure that client process and/or message is authenticated so that anonymous communications and/or messages are not accepted by the system.
Design: Do not rely on client validation or encoding for security purposes.
Design: Utilize digital signatures to increase authentication assurance.
Design: Utilize two factor authentication to increase authentication assurance.
Implementation: Perform input validation for all remote content.
Weaknesses it exploits
- CWE-20 Improper Input Validation
- CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
- CWE-287 Improper Authentication
- CWE-290 Authentication Bypass by Spoofing
- CWE-693 Protection Mechanism Failure
Recent CVEs with these weaknesses
- 4.9CVE-2026-105427
Improper input validation in Ivanti EPMM before version 12.10.0.1, 12.9.0.3, and 12.8.0.5 allows a remote authenticated attacker with admin privileges to permanently disable all Apache HTTPS services resulting in denial of service.
- 6.7CVE-2026-105426
Improper input validation in Ivanti EPMM before version 12.10.0.1, 12.9.0.3, and 12.8.0.5 allows a remote authenticated attacker with admin privileges to set arbitrary Linux kernel parameters as root.
- –CVE-2026-97874
When Hessian remoting is configured with BASIC authentication, the authentication check is not applied to Hessian endpoints of applications deployed under a non-root context path. A remote unauthenticated attacker can invoke the exposed EJ…
- –CVE-2026-97880
The embedded OpenEJB HTTP server dispatches some requests to REST endpoints configured for HTTP Basic authentication without verifying credentials. A remote unauthenticated attacker can invoke protected resources, bypassing authentication.…
- 9.6CVE-2026-108186
Improper Input Validation in Zoom Workplace for Windows may allow an unauthenticated user to conduct an escalation of privilege via network access.
- –CVE-2026-111240
The JDBC based JAAS login module accepts a login without a password for accounts whose stored password is NULL. A remote attacker who knows the user name of such an account can authenticate as that user and obtain its roles. Only deploymen…
- –CVE-2026-111250
The embedded OpenEJB HTTP server reports every request as authenticated when an application requests authentication programmatically. A remote unauthenticated attacker can access functionality protected this way. Only applications served b…
- –CVE-2026-111261
The Jakarta Security LDAP identity store accepts an empty password as valid if the directory server allows unauthenticated binds, which some directory servers do by default. A remote attacker can then authenticate as any existing user with…
The newest records naming one of them. Each weakness's page lists them all.
Related attack patterns
Examples
Web applications may use JavaScript to perform client side validation, request encoding/formatting, and other…
Web applications may use JavaScript to perform client side validation, request encoding/formatting, and other security functions, which provides some usability benefits and eliminates some client-server round-tripping. However, the web server cannot assume that the requests it receives have been subject to those validations, because an attacker can use an alternate method for crafting the HTTP Request and submit data that contains poisoned values designed to spoof a user and/or get the web server to disclose information.
Web 2.0 style applications may be particularly vulnerable because they in large part rely on existing infrast…
Web 2.0 style applications may be particularly vulnerable because they in large part rely on existing infrastructure which provides scalability without the ability to govern the clients. Attackers identify vulnerabilities that either assume the client side is responsible for some security services (without the requisite ability to ensure enforcement of these checks) and/or the lack of a hardened, default deny server configuration that allows for an attacker probing for weaknesses in unexpected ways. Client side validation, request formatting and other services may be performed, but these are strictly usability enhancements not security enhancements.
Many web applications use client side scripting like JavaScript to enforce authentication, authorization, ses…
Many web applications use client side scripting like JavaScript to enforce authentication, authorization, session state and other variables, but at the end of day they all make requests to the server. These client side checks may provide usability and performance gains, but they lack integrity in terms of the http request. It is possible for an attacker to post variables directly to the server without using any of the client script security checks and customize the patterns to impersonate other users or probe for more information.
Many message oriented middleware systems like MQ Series are rely on information that is passed along with the…
Many message oriented middleware systems like MQ Series are rely on information that is passed along with the message request for making authorization decisions, for example what group or role the request should be passed. However, if the message server does not or cannot authenticate the authorization information in the request then the server's policy decisions about authorization are trivial to subvert because the client process can simply elevate privilege by passing in elevated group or role information which the message server accepts and acts on.
MITRE's words, unchanged: CAPEC-22 at MITRE. CAPEC is Copyright © 2007–2026, The MITRE Corporation, used under the CAPEC terms of use: “The MITRE Corporation (MITRE) hereby grants you a non-exclusive, royalty-free license to use Common Attack Pattern Enumeration and Classification (CAPEC™) for research, development, and commercial purposes. Any copy you make for such purposes is authorized provided that you reproduce MITRE’s copyright designation and this license in any such copy.” CAPEC and the CAPEC logo are trademarks of The MITRE Corporation. Credits. All attack patterns.