Official definition

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

There are many different kinds of mistakes that introduce information exposures. The severity of the error can range widely, depending on the context in which the product operates, the type of sensitive information that is revealed, and the benefits it may provide to an attacker. Some kinds of sensitive information include:

private, personal information, such as personal messages, financial data, health records, geographic location, or contact details
system status and environment, such as the operating system and installed packages
business secrets and intellectual property
network status and configuration
the product's own code or internal state
metadata, e.g. logging of connections or message headers
indirect information, such as a discrepancy between two internal operations that can be observed by an outsider

Information might be sensitive to different parties, each of which may have their own expectations for whether the information should be protected. These parties include:

the product's own users
people or organizations whose information is created or used by the product, even if they are not direct product users
the product's administrators, including the admins of the system(s) and/or networks on which the product operates
the developer

Information exposures can occur in different ways:

the code explicitly inserts sensitive information into resources or messages that are intentionally made accessible to unauthorized actors, but should not contain the information - i.e., the information should have been "scrubbed" or "sanitized"
a different weakness or mistake indirectly inserts the sensitive information into resources, such as a web script error revealing the full system path of the program.
the code manages resources that intentionally contain sensitive information, but the resources are unintentionally made accessible to unauthorized actors. In this case, the information exposure is resultant - i.e., a different weakness enabled the access to the information in the first place.

It is common practice to describe any loss of confidentiality as an "information exposure," but this can lead to overuse of CWE-200 in CWE mapping. From the CWE perspective, loss of confidentiality is a technical impact that can arise from dozens of different weaknesses, such as insecure file permissions or out-of-bounds read. CWE-200 and its lower-level descendants are intended to cover the mistakes that occur in behaviors that explicitly manage, store, transfer, or cleanse sensitive information.

Characteristics

Alternate terms

Information Disclosure — This term is frequently used in vulnerability advisories to describe a consequence or technical impact, for any vulnerability that has a loss of confidentiality. Often, CWE-200 can be misused to represent the loss of confidentiality, even when the mistake - i.e., the weakness - is not directly related to the mishandling of the information itself, such as an out-of-bounds read that accesses sensitive memory contents; here, the out-of-bounds read is the primary weakness, not the disclosure of the memory. In addition, this phrase is also used frequently in policies and legal documents, but it does not refer to any disclosure of security-relevant information.
Information Leak — This is a frequently used term, however the "leak" term has multiple uses within security. In some cases it deals with the accidental exposure of information from a different weakness, but in other cases (such as "memory leak"), this deals with improper tracking of resources, which can lead to exhaustion. As a result, CWE is actively avoiding usage of the "leak" term.

Modes of introduction

Architecture and Design
Implementation

Common consequences

Impact	Scope	Explanation
Read Application Data	Confidentiality	—

Risk mitigations

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

Method	Approach	Effectiveness
Automated Static Analysis - Binary or Bytecode	According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Bytecode Weakness Analysis - including disassembler + source code weakness analysis Inter-application Flow Analysis	SOAR Partial
Dynamic Analysis with Automated Results Interpretation	According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Web Application Scanner Web Services Scanner Database Scanners	High
Dynamic Analysis with Manual Results Interpretation	According to SOAR [REF-1479], the following detection techniques may be useful: ``` Cost effective for partial coverage: ``` Fuzz Tester Framework-based Fuzzer Automated Monitored Execution Monitored Virtual Environment - run potentially malicious code in sandbox / wrapper / virtual machine, see if it does anything suspicious	SOAR Partial
Manual Static Analysis - Source Code	According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Manual Source Code Review (not inspections)	High
Automated Static Analysis - Source Code	According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Context-configured Source Code Weakness Analyzer ``` Cost effective for partial coverage: ``` Source code Weakness Analyzer	High
Architecture or Design Review	According to SOAR [REF-1479], the following detection techniques may be useful: ``` Highly cost effective: ``` Formal Methods / Correct-By-Construction ``` Cost effective for partial coverage: ``` Attack Modeling Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)	High

Representative vulnerabilities

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

Sources (5)

MITRE CWE

CWE Terms of Use Supplemental Details - 2022 CWE Top 25

veracode.com

ida.org

CWE-200: Exposure of Sensitive Information to an Unauthorized Actor

What is CWE-200?

Data statistics

Vulnerabilities mapped to CWE-200

Vulnerabilities in CISA KEV for CWE-200