SiteGuard — Local Security Advisor

Local-First Browser Security Scanner Protect your browsing with a practical, transparent, and privacy-conscious browser security scanner designed to help users understand common security risks on websites they visit. This extension performs security checks directly in the browser and provides an easy-to-understand 0 to 100 risk score based on observable security indicators. Instead of simply reporting that a website is safe or unsafe, it presents evidence and explanations to help users understand why a particular security issue may matter. Key Security Checks The extension evaluates several important aspects of website security, including: HTTPS and TLS security: Checks whether a website uses HTTPS and identifies relevant transport security indicators. Security headers: Examines commonly used HTTP security headers and highlights missing or potentially weak configurations. Cookie security: Checks security-related cookie attributes such as Secure, HttpOnly, and SameSite where accessible. Mixed content: Identifies situations where secure pages may request resources through insecure connections. Redirect chains: Examines website redirections and helps users understand the sequence of redirects before reaching the final destination. Phishing-style URL indicators: Evaluates URL characteristics that may be associated with suspicious or deceptive web addresses. Risk scoring: Provides a transparent 0 to 100 score to summarize the observed security indicators. Transparent Risk Assessment The extension is designed to make browser security information understandable to both technical and non-technical users. Each identified issue is accompanied by an explanation and supporting evidence wherever possible. The risk score is intended as an informative security assessment rather than a guarantee that a website is safe or malicious. A high or low score should be interpreted together with the individual findings and the context in which the website is being accessed. Privacy-Conscious and Local-First Design Privacy is an important part of the extension's design. Security analysis is intended to be performed locally within the browser wherever technically possible. The extension does not require users to submit every website they visit to a remote security analysis service simply to obtain a basic security assessment. The local-first approach helps reduce unnecessary data transmission and gives users greater visibility into how security checks are performed. Designed for Security Awareness The extension can be useful for: Students and researchers learning about web security Developers and web administrators reviewing website configurations Security-conscious users evaluating unfamiliar websites Educators demonstrating common web security concepts Researchers studying browser-based security assessment techniques Users who want a quick overview of observable website security indicators Evidence-Based Results The extension focuses on observable technical indicators rather than relying solely on a single external reputation database. Findings are presented with relevant details so that users can better understand the underlying security condition. For example, instead of simply reporting that a security header is missing, the extension can identify the relevant header and explain its general security purpose. Similarly, URL-related findings are presented as indicators that may warrant additional attention rather than as definitive claims that a website is malicious. Important Notice This extension is intended as a security assessment and awareness tool. A risk score does not constitute a guarantee of website safety, authenticity, or malicious intent. Security conditions can change, and some security properties cannot be completely determined from a browser-based assessment. Users should exercise appropriate caution when visiting unfamiliar websites, entering sensitive information, downloading files, or responding to requests for credentials or financial information. The extension is designed to provide useful security information while keeping the assessment transparent, understandable, and privacy-conscious.