CWE-454: External Initialization of Trusted Variables or Data Stores

BaseDraft

The product initializes critical internal variables or data stores using inputs that can be modified by untrusted actors.

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Extended Description

A product system should be reluctant to trust variables that have been initialized outside of its trust boundary, especially if they are initialized by users. The variables may have been initialized incorrectly. If an attacker can initialize the variable, then they can influence what the vulnerable system will do.

Technical Details

Structure
Simple
Vulnerability Mapping
ALLOWED

Applicable To

Languages
PHPNot Language-Specific
Platforms

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Verify controls for CWE-454 with SSDF evidence

Use NIST SSDF verification and vulnerability-response practices to detect CWE-454, External Initialization of Trusted Variables or Data Stores, throughout the product lifecycle. Derive review questions, static or dynamic checks, and negative tests from the CWE's causal behavior; define the components and lifecycle stages each check covers; and retain findings with enough evidence to distinguish the root cause from symptoms and impacts. Track escapes and false negatives, then improve the verification plan after every confirmed occurrence.

NIST SP 800-218 Secure Software Development Framework — National Institute of Standards and Technology

Apply Input Validation controls for External Initialization of Trusted Variables or Data Stores

MITRE associates mitigation with Implementation, and Architecture and Design; the listed strategies include Input Validation; documented detection approaches include Automated Static Analysis. Use these source-defined anchors to turn CWE-454 into implementation, review, and verification checks for the affected component.

CWE-454: External Initialization of Trusted Variables or Data Stores — MITRE CWE

Triage CWE-454 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-454, External Initialization of Trusted Variables or Data Stores, has evidence of exploitation in the wild. Confirm the CVE-to-CWE root-cause mapping independently before attaching the example, then capture the affected product, required action, and remediation deadline. A missing KEV match is not evidence that the weakness is unexploited, and a KEV entry must not be generalized to every occurrence of this CWE.

Known Exploited Vulnerabilities Catalog — Cybersecurity and Infrastructure Security Agency

Apply precise root-cause mapping to CWE-454

Apply MITRE's full root-cause mapping guidance when using CWE-454, External Initialization of Trusted Variables or Data Stores. Separate weakness language from attacker prerequisites and technical impact, check the entry's abstraction and vulnerability-mapping notes, and prefer the most specific Base or Variant supported by the evidence. Record the rejected alternatives and require an independent review before the mapping is used for remediation trends or program metrics.

CVE to CWE Root Cause Mapping Guidance — MITRE CWE

Validate CWE-454 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-454, External Initialization of Trusted Variables or Data Stores. Confirm the finding describes the causal weakness rather than an impact or attack pattern, compare the abstraction and mapping notes with plausible alternatives, and have a second reviewer challenge the selection. Preserve the evidence and reasoning so recurring defects can be measured against one consistent identifier.

CVE to CWE Root Cause Mapping Quick Tips — MITRE CWE

Frequently Asked Questions

What is CWE-454: External Initialization of Trusted Variables or Data Stores?+

CWE-454: External Initialization of Trusted Variables or Data Stores is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product initializes critical internal variables or data stores using inputs that can be modified by untrusted actors. A product system should be reluctant to trust variables that have been initialized outside of its trust boundary, especially if they are initialized by users. The variables may have been initialized incorrectly. If an attacker can initialize the variable, then they can influence what the vulnerable system will do.

What are the security consequences of External Initialization of Trusted Variables or Data Stores?+

If exploited, CWE-454 (External Initialization of Trusted Variables or Data Stores) it can compromise Integrity, leading to outcomes such as Modify Application Data.

How do you prevent or mitigate External Initialization of Trusted Variables or Data Stores?+

Recommended mitigations for CWE-454 include: A product system should be reluctant to trust variables that have been initialized outside of its trust boundary. Ensure adequate checking (e.g. input validation) is performed when relying on input from outside a trust boundary. Avoid any external control of variables. If necessary, restrict the variables that can be modified using an allowlist, and use a different namespace or naming convention if possible.

Which programming languages are affected by External Initialization of Trusted Variables or Data Stores?+

CWE-454 commonly affects PHP and Not Language-Specific. Note that weaknesses are often language-agnostic patterns, so secure coding practices apply broadly.

What are real-world examples of External Initialization of Trusted Variables or Data Stores?+

MITRE documents real CVEs mapped to CWE-454, including CVE-2022-43468, CVE-2000-0959, CVE-2001-0033, CVE-2001-0872 and CVE-2001-0084. 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-454 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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