CWE-618 Variant Incomplete

Exposed Unsafe ActiveX Method

This vulnerability occurs when an ActiveX control, designed for web browsers, exposes methods that bypass the browser's built-in security restrictions. These unsafe methods can perform actions…

Definition

What is CWE-618?

This vulnerability occurs when an ActiveX control, designed for web browsers, exposes methods that bypass the browser's built-in security restrictions. These unsafe methods can perform actions outside the browser's intended security boundaries, such as those defined by zones or domains.
ActiveX controls operate with high-level system permissions, granting them far more access to the operating system than standard web scripts like JavaScript. When a control exposes a method without proper safeguards, attackers can potentially invoke it from a malicious webpage. The risk level depends entirely on what the exposed method does and whether it validates any input it receives. Without checks to verify the origin or integrity of the call, these dangerous methods become an open gateway. Attackers can exploit them to perform unauthorized actions on a user's system, directly from the browser. The core issue is the combination of excessive system privileges and a lack of validation for who is calling the method or what data they are sending.
Real-world impact

Real-world CVEs caused by CWE-618

How attackers exploit it

Step-by-step attacker path

  1. 1

    Identify a code path that handles untrusted input without validation.

  2. 2

    Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.

  3. 3

    Deliver the payload through a normal request and observe the application's reaction.

  4. 4

    Iterate until the response leaks data, executes attacker code, or escalates privileges.

Vulnerable code example

Vulnerable pseudo

MITRE has not published a code example for this CWE. The pattern below is illustrative — see Resources for canonical references.

Vulnerable pseudo 
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
  // Untrusted input flows directly into the sensitive sink.
  return executeUnsafe(input);
}
Secure code example

Secure pseudo

Secure pseudo 
// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
  const safe = validateAndEscape(input);
  return executeWithGuards(safe);
}
What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Prevention checklist

How to prevent CWE-618

  • Implementation If you must expose a method, make sure to perform input validation on all arguments, and protect against all possible vulnerabilities.
  • Architecture and Design Use code signing, although this does not protect against any weaknesses that are already in the control.
  • Architecture and Design / System Configuration Where possible, avoid marking the control as safe for scripting.
Detection signals

How to detect CWE-618

Automated Static Analysis High

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.)

Plexicus auto-fix

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Frequently asked questions

Frequently asked questions

What is CWE-618?

This vulnerability occurs when an ActiveX control, designed for web browsers, exposes methods that bypass the browser's built-in security restrictions. These unsafe methods can perform actions outside the browser's intended security boundaries, such as those defined by zones or domains.

How serious is CWE-618?

MITRE has not published a likelihood-of-exploit rating for this weakness. Treat it as medium-impact until your threat model proves otherwise.

What languages or platforms are affected by CWE-618?

MITRE has not specified affected platforms for this CWE — it can apply across most application stacks.

How can I prevent CWE-618?

If you must expose a method, make sure to perform input validation on all arguments, and protect against all possible vulnerabilities. Use code signing, although this does not protect against any weaknesses that are already in the control.

How does Plexicus detect and fix CWE-618?

Plexicus's SAST engine matches the data-flow signature for CWE-618 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.

Where can I learn more about CWE-618?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/618.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-618

CWE-749 Parent

Exposed Dangerous Method or Function

This vulnerability occurs when a software component exposes an API or interface containing a high-risk function that lacks proper access…

CWE-782 Sibling

Exposed IOCTL with Insufficient Access Control

This vulnerability occurs when a system exposes an IOCTL (Input/Output Control) interface that performs sensitive operations, but fails to…

Resources

Further reading

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