Dranzer is an open-source cybersecurity fuzzer developed by the CERT Coordination Center (CERT/CC) specifically designed to discover security vulnerabilities in ActiveX controls and Component Object Model (COM) objects.
While the tool is traditionally executed via a Command-Line Interface (CLI) using automated script arguments, independent security researchers often package it with a Graphical User Interface (GUI) wrapper to simplify the testing pipeline. Tool Overview
ActiveX and COM technologies allow web browsers like Internet Explorer to interact with software installed locally on Windows machines. Attackers often exploit poorly constructed components to achieve arbitrary code execution or cause memory corruption. The Dranzer architecture works by fuzzing—automatically feeding malformed data, unexpected arguments, and extreme boundary values into these components—to see if they crash or misbehave. Target Vulnerability Classes
Dranzer segments its testing routines into three core classes:
Class I (Instantiation Crashes): Checks if a COM object immediately crashes the browser environment when initialized.
Class II (Input Validation Flaws): Tests how cleanly an object validates text inputs, properties, methods, and initialization parameters. It dynamically checks available parameters using binary scanning or the IPropertyBag interface.
Class III (Scripting Risks): Scans for and enumerates methods or properties belonging to COM objects specifically marked “Safe for Scripting,” as these pose the highest risk of unauthorized remote exploitation. Key Features of a Dranzer GUI Framework
When a GUI wrapper is applied to Dranzer’s framework, it typically exposes the underlying CLI features into simple visual configurations:
Automated CLSID Enumeration: Allows users to quickly generate a baseline list of all COM objects installed on a local machine rather than having to manually track down Class Identifiers (CLSIDs).
Exception and Kill Bit Management: Provides easy visual controls to flag specific items on a “don’t test” list or quickly identify objects that have a Microsoft Kill Bit applied (preventing them from running in the browser).
Targeted Scanning Toggles: Replaces CLI arguments (-b, -t, -p, -s, etc.) with user-friendly checkboxes so testers can dictate whether they want to run a fast binary scan, check property bags, or probe browser methods.
Log Exporting and Analysis: Includes designated fields to define an output text file destination. It visually displays formatting templates so developers can quickly pinpoint exactly which parameter caused a top-level execution error. Who Benefits from the Tool?
Software Developers: Can test custom COM objects locally during active development cycles. This stops security loopholes from reaching public software releases.
System Administrators: Use it to conduct proactive threat assessments. It uncovers hidden risks tied to third-party ActiveX controls installed across corporate networks.
Are you currently aiming to run tests on a specific legacy application, or
Dranzer is a tool that enables users to examine … – GitHub
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