Grammarly Ai Writing Assi

The extension loads scripts from external domains directly inside its background service worker. This could allow attackers to inject malicious code if those sources are compromised.

Technical: Code pattern: Dynamic script loading via fetch() or eval(). Risk vector: If an attacker controls one of the loaded URLs (e.g., assets.extension.grammarly.com), they can execute arbitrary JavaScript in the extension context.

💡 Common practice for extensions that rely on external libraries or dynamic updates, but requires strict validation and secure delivery mechanisms.

The extension dynamically imports JavaScript modules at runtime. While typical for modern apps, this can obscure behavior or introduce unexpected code paths.

Technical: Code pattern: import() statements used to load scripts conditionally based on user actions or environment. Risk vector: Could be leveraged to bypass CSP restrictions if not carefully controlled.

💡 Standard in large applications where modules are loaded only when needed, improving performance and modularity.

The extension injects HTML content using innerHTML. If not sanitized properly, this could allow cross-site scripting (XSS) attacks if user input is included.

Technical: Code pattern: element.innerHTML = userInput; Risk vector: Potential XSS if untrusted data enters the DOM without sanitization or escaping.

💡 Common in UI rendering logic where dynamic content needs to be inserted into elements, but must always validate inputs.

The extension uses obfuscated strings (e.g., String.fromCharCode) which may hide malicious behavior or code within otherwise benign-looking scripts.

Technical: Code pattern: var x = String.fromCharCode(102, 111, 111); Risk vector: Makes static analysis harder; could be used to conceal malware payloads or communication patterns.

💡 Used for obfuscating strings in legitimate code (e.g., API keys) but also common in malicious software to evade detection.

The extension opens real-time WebSocket connections for live communication with Grammarly's servers. This is normal for AI-powered tools but requires secure handling of data streams.

Technical: Code pattern: new WebSocket('wss://capi.grammarly.com'); Risk vector: If connection isn't properly secured or authenticated, could leak user content to unauthorized parties.

💡 Standard in real-time collaborative and AI services where immediate feedback is required (e.g., grammar suggestions).

The extension creates script elements dynamically, which can be used to inject code into web pages or load external resources. This increases the risk of injection attacks.

Technical: Code pattern: document.createElement('script'); Risk vector: Could allow execution of malicious scripts if source is not trusted or controlled by developer.

💡 Used in extensions that need to run third-party libraries on webpages, but must be done carefully with strict origin checks.

The extension captures every keystroke you type across all websites. This is a major privacy concern as it gives the extension access to sensitive information like passwords or personal messages.

Technical: Code pattern: Event listeners on document.body for keydown/keyup events; Risk vector: Full keyboard logging without user awareness, potentially exposing private data.

💡 Used in some productivity tools that analyze writing patterns or provide predictive text features. However, this level of access is excessive unless clearly explained and opt-in.

The extension can read what’s in your clipboard, which may include sensitive data like passwords or private messages. This could be used to track user activity or steal information.

Technical: Code pattern: chrome.clipboard.read(); Risk vector: If combined with keystroke logging, allows full tracking of copied/pasted content across sites.

💡 Used in extensions that help users paste formatted text or rewrite content from clipboard. But should be limited to specific use cases and clearly disclosed.

Some code may contain hardcoded secrets (like API keys). If these are exposed, attackers could impersonate the extension or access backend systems.

Technical: Code pattern: const apiKey = 'secret_key_here'; Risk vector: Hardcoded credentials in source files can be extracted by reverse engineering or public repositories.

💡 Common during development but should never appear in production builds. Should always use secure credential management practices.

The extension uses postMessage to communicate with other domains (e.g., embedded iframes or external tools). If not handled securely, this could allow data leakage.

Technical: Code pattern: window.postMessage(data, targetOrigin); Risk vector: Improper validation of origins can lead to information disclosure between unrelated sites.

💡 Standard for secure cross-origin communication in web apps. Requires careful handling of allowed domains and message content.