CWE-749 Detail

The product provides an Applications Programming Interface (API) or similar interface for interaction with external actors, but the interface includes a dangerous method or function that is not properly restricted.

This weakness can lead to a wide variety of resultant weaknesses, depending on the behavior of the exposed method. It can apply to any number of technologies and approaches, such as ActiveX controls, Java functions, IOCTLs, and so on.

The exposure can occur in a few different ways:

• The function/method was never intended to be exposed to outside actors.
• The function/method was only intended to be accessible to a limited set of actors, such as Internet-based access from a single web site.

Modes Of Introduction

Architecture and Design
Implementation

Applicable Platforms

Language

Class: Not Language-Specific (Undetermined)

Common Consequences

Observed Examples

Potential Mitigations

Phases : Architecture and Design
If you must expose a method, make sure to perform input validation on all arguments, limit access to authorized parties, and protect against all possible vulnerabilities.
Phases : Architecture and Design // Implementation

Identify all exposed functionality. Explicitly list all functionality that must be exposed to some user or set of users. Identify which functionality may be:

• accessible to all users
• restricted to a small set of privileged users
• prevented from being directly accessible at all

Ensure that the implemented code follows these expectations. This includes setting the appropriate access modifiers where applicable (public, private, protected, etc.) or not marking ActiveX controls safe-for-scripting.

Detection Methods

Automated Static Analysis

Automated 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.)
Effectiveness : High

Vulnerability Mapping Notes

Justification : This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comment : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

Related Attack Patterns

NotesNotes

Under-reported and under-studied. This weakness could appear in any technology, language, or framework that allows the programmer to provide a functional interface to external parties, but it is not heavily reported. In 2007, CVE began showing a notable increase in reports of exposed method vulnerabilities in ActiveX applications, as well as IOCTL access to OS-level resources. These weaknesses have been documented for Java applications in various secure programming sources, but there are few reports in CVE, which suggests limited awareness in most parts of the vulnerability research community.

References

REF-503

Developing Secure ActiveX Controls
Microsoft.
https://learn.microsoft.com/en-us/previous-versions//ms533046(v=vs.85)?redirectedfrom=MSDN

REF-510

How to stop an ActiveX control from running in Internet Explorer
Microsoft.
https://support.microsoft.com/en-us/help/240797/how-to-stop-an-activex-control-from-running-in-internet-explorer

Submission

Modifications