CWE-603: Use of Client-Side Authentication

BaseDraft

A client/server product performs authentication within client code but not in server code, allowing server-side authentication to be bypassed via a modified client that omits the authentication check.

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Extended Description

Client-side authentication is extremely weak and may be breached easily. Any attacker may read the source code and reverse-engineer the authentication mechanism to access parts of the application which would otherwise be protected.

Technical Details

Structure
Simple

Applicable To

Languages
Not Language-Specific
Platforms

Frequently Asked Questions

What is CWE-603: Use of Client-Side Authentication?+

CWE-603: Use of Client-Side Authentication is a Common Weakness Enumeration (CWE) entry maintained by MITRE. A client/server product performs authentication within client code but not in server code, allowing server-side authentication to be bypassed via a modified client that omits the authentication check. Client-side authentication is extremely weak and may be breached easily. Any attacker may read the source code and reverse-engineer the authentication mechanism to access parts of the application which would otherwise be protected.

What are the security consequences of Use of Client-Side Authentication?+

If exploited, CWE-603 (Use of Client-Side Authentication) it can compromise Access Control, leading to outcomes such as Bypass Protection Mechanism and Gain Privileges or Assume Identity.

How do you prevent or mitigate Use of Client-Side Authentication?+

Recommended mitigations for CWE-603 include: Do not rely on client side data. Always perform server side authentication.

Which programming languages are affected by Use of Client-Side Authentication?+

CWE-603 commonly affects Not Language-Specific. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

What are real-world examples of Use of Client-Side Authentication?+

MITRE documents real CVEs mapped to CWE-603, including CVE-2022-33139 and CVE-2006-0230. You can look up the full details of each CVE, including CVSS scores and remediation guidance, on our CVE Lookup tool.

What is the difference between a CWE and a CVE?+

A CWE (Common Weakness Enumeration) like CWE-603 describes a category of software weakness — the underlying flaw type. A CVE (Common Vulnerabilities and Exposures) identifies a specific, real-world vulnerability in a particular product. In short, a CWE is the kind of mistake, and a CVE is an instance of that mistake being found in software.

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