Exposed Dangerous Method or Function

Opis

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.

Skutki

• Integrity, Confidentiality, Availability, Access Control, Other

  Gain Privileges or Assume Identity; Read Application Data; Modify Application Data; Execute Unauthorized Code or Commands; Other

  Exposing critical functionality essentially provides an attacker with the privilege level of the exposed functionality. This could result in the modification or exposure of sensitive data or possibly even execution of arbitrary code.

Zapobieganie

• 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.

• Architecture and Design, Implementation · Attack Surface Reduction

  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.

Przykłady podatności

• CVE-2007-6382 arbitrary Java code execution via exposed method
• CVE-2007-1112 security tool ActiveX control allows download or upload of files

Słabość nadrzędna

• CWE-284 Improper Access Control

Słabości podrzędne

• CWE-618 Exposed Unsafe ActiveX Method
• CWE-782 Exposed IOCTL with Insufficient Access Control

Kiedy powstaje

• Architecture and Design
• Implementation

Dotyczy

Not Language-Specific

Uwagi

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.

Źródła

1. Developing Secure ActiveX Controls — Microsoft, 2005
2. How to stop an ActiveX control from running in Internet Explorer — Microsoft