CWE-923: Improper Restriction of Communication Channel to Intended Endpoints

Extended Description

Attackers might be able to spoof the intended endpoint from a different system or process, thus gaining the same level of access as the intended endpoint. While this issue frequently involves authentication between network-based clients and servers, other types of communication channels and endpoints can have this weakness.

Code Examples & CVEs

Demonstrative Examples

These cross-domain policy files mean to allow Flash and Silverlight applications hosted on other domains to access its data:

Flash crossdomain.xml :

BadXML

<cross-domain-policy xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:noNamespaceSchemaLocation="http://www.adobe.com/xml/schemas/PolicyFile.xsd"><allow-access-from domain="*.example.com"/><allow-access-from domain="*"/></cross-domain-policy>

These cross-domain policy files mean to allow Flash and Silverlight applications hosted on other domains to access its data:

Flash crossdomain.xml :

BadXML

<?xml version="1.0" encoding="utf-8"?><access-policy><cross-domain-access><policy><allow-from http-request-headers="SOAPAction"><domain uri="*"/></allow-from><grant-to><resource path="/" include-subpaths="true"/></grant-to></policy></cross-domain-access></access-policy>

This Android application will remove a user account when it receives an intent to do so:

This application does not check the origin of the intent, thus allowing any malicious application to remove a user. Always check the origin of an intent, or create an allowlist of trusted applications using the manifest.xml file.

BadJava

IntentFilter filter = new IntentFilter("com.example.RemoveUser");MyReceiver receiver = new MyReceiver();registerReceiver(receiver, filter);                      public class DeleteReceiver extends BroadcastReceiver {@Overridepublic void onReceive(Context context, Intent intent) {int userID = intent.getIntExtra("userID");destroyUserData(userID);}}

Observed CVE Examples (7)

CVE-2022-30319

S-bus functionality in a home automation product performs access control using an IP allowlist, which can be bypassed by a forged IP address.

View Details

CVE-2022-22547

A troubleshooting tool exposes a web server on a random port between 9000-65535 that could be used for information gathering

View Details

CVE-2022-4390

A WAN interface on a router has firewall restrictions enabled for IPv4, but it does not for IPv6, which is enabled by default

View Details

CVE-2012-2292

Product has a Silverlight cross-domain policy that does not restrict access to another application, which allows remote attackers to bypass the Same Origin Policy.

View Details

CVE-2012-5810

Mobile banking application does not verify hostname, leading to financial loss.

View Details

CVE-2014-1266

Chain: incorrect "goto" in Apple SSL product bypasses certificate validation, allowing Adversary-in-the-Middle (AITM) attack (Apple "goto fail" bug). CWE-705 (Incorrect Control Flow Scoping) -> CWE-561 (Dead Code) -> CWE-295 (Improper Certificate Validation) -> CWE-393 (Return of Wrong Status Code) -> CWE-300 (Channel Accessible by Non-Endpoint). The code's whitespace indentation did not reflect the actual control flow (CWE-1114) and did not explicitly delimit the block (CWE-483), which could have made it more difficult for human code auditors to detect the vulnerability.

View Details

CVE-2000-1218

DNS server can accept DNS updates from hosts that it did not query, leading to cache poisoning

View Details

Source-backed guidance

Additional facts reviewed against primary or authoritative security sources.

Detect Improper Restriction of Communication Channel to Intended Endpoints with Automated Static Analysis

Documented detection approaches include Automated Static Analysis; recorded impacts include Gain Privileges or Assume Identity; the entry maps to CAPEC-161, CAPEC-481, CAPEC-501, and CAPEC-697. Use these source-defined anchors to turn CWE-923 into implementation, review, and verification checks for the affected component.

CWE-923: Improper Restriction of Communication Channel to Intended Endpoints — MITRE CWE

Prevent CWE-923 through an SSDF control plan

Use NIST SSDF practices to make prevention of CWE-923, Improper Restriction of Communication Channel to Intended Endpoints, an explicit development outcome. Translate the CWE definition into security requirements and design constraints, choose safer implementation patterns and toolchain checks, and define acceptance evidence before release. Feed every confirmed occurrence back into the requirements, design review, and coding rules so the same root cause is removed across the product rather than patched in one location.

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

Triage CWE-923 against known exploitation evidence

Use CISA's Known Exploited Vulnerabilities catalog to test whether a vulnerability mapped to CWE-923, Improper Restriction of Communication Channel to Intended Endpoints, 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-923

Apply MITRE's full root-cause mapping guidance when using CWE-923, Improper Restriction of Communication Channel to Intended Endpoints. 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-923 with root-cause mapping checks

Apply MITRE's root-cause mapping quick tips to CWE-923, Improper Restriction of Communication Channel to Intended Endpoints. 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-923: Improper Restriction of Communication Channel to Intended Endpoints?+

CWE-923: Improper Restriction of Communication Channel to Intended Endpoints is a Common Weakness Enumeration (CWE) entry maintained by MITRE. The product establishes a communication channel to (or from) an endpoint for privileged or protected operations, but it does not properly ensure that it is communicating with the correct endpoint. Attackers might be able to spoof the intended endpoint from a different system or process, thus gaining the same level of access as the intended endpoint. While this issue frequently involves authentication between network-based clients and servers, other types of communication channels and endpoints can have this weakness.

What are the security consequences of Improper Restriction of Communication Channel to Intended Endpoints?+

If exploited, CWE-923 (Improper Restriction of Communication Channel to Intended Endpoints) it can compromise Integrity and Confidentiality, leading to outcomes such as Gain Privileges or Assume Identity.

Which programming languages are affected by Improper Restriction of Communication Channel to Intended Endpoints?+

CWE-923 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 Improper Restriction of Communication Channel to Intended Endpoints?+

MITRE documents real CVEs mapped to CWE-923, including CVE-2022-30319, CVE-2022-22547, CVE-2022-4390, CVE-2012-2292 and CVE-2012-5810. 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-923 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.

CWE-923: Improper Restriction of Communication Channel to Intended Endpoints

Extended Description

Technical Details

Applicable To

Security Consequences

Scope

Impact

Mitigation Strategies

Detection Methods

Code Examples & CVEs

Demonstrative Examples

Observed CVE Examples (7)

CWE Relationships

Parent Weaknesses

Source-backed guidance

Detect Improper Restriction of Communication Channel to Intended Endpoints with Automated Static Analysis

Prevent CWE-923 through an SSDF control plan

Triage CWE-923 against known exploitation evidence

Apply precise root-cause mapping to CWE-923

Validate CWE-923 with root-cause mapping checks

Frequently Asked Questions

Learn More