CWE-201: Insertion of Sensitive Information Into Sent Data

What is CWE-201?

CWE-201 is Insertion of Sensitive Information Into Sent Data. The flaw arises when the code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor. The database currently holds 185 vulnerabilities mapped to CWE-201 and none of them are in the CISA Known Exploited Vulnerabilities catalog.

Analyzing data...

OWASP TOP 10:2025 RANK1 — A01:2025 — Broken Access Control
Related CVES (365 days)185
AbstractionBase
Likelihood of exploit-

Vulnerabilities mapped to CWE-201

185 vulnerabilities311% increase year over year

No data

No vulnerability data in CISA KEV for CWE-201

Official definition

ByMitre CWE

The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor.

Characteristics

Modes of introduction

  • Architecture and Design
  • Implementation: REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Common consequences

ImpactScopeExplanation
Read Files or Directories, Read Memory, Read Application DataConfidentialitySensitive data may be exposed to attackers.

Risk mitigations

  1. RequirementsSpecify which data in the software should be regarded as sensitive. Consider which types of users should have access to which types of data.
  2. ImplementationEnsure that any possibly sensitive data specified in the requirements is verified with designers to ensure that it is either a calculated risk or mitigated elsewhere. Any information that is not necessary to the functionality should be removed in order to lower both the overhead and the possibility of security sensitive data being sent.
  3. System ConfigurationSetup default error messages so that unexpected errors do not disclose sensitive information.
  4. Separation of Privilege · Architecture and DesignCompartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

Detection methods

MethodApproachEffectiveness
Automated Static AnalysisAutomated 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.)High

Representative vulnerabilities

Below are representative vulnerabilities related to this CWE, prioritized by severity.

Sources (2)
MITRE CWE
CWE Terms of Use

Supporting documents

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