Septimius - Phishing Detector by Isaac Elazzabi

Septimius warns you before a phishing site can trick you.

What it does
- Checks every website you open for the signs of phishing: lookalike addresses (like paypa1.com), look-alike characters, missing HTTPS, suspicious address patterns, and phrases such as "verify your account".
- Compares each site name with a threat database built from the public URLhaus feed (abuse.ch).
- For a known threat, or a site with several strong warning signs, it can replace the page with a full-page warning. You can go back to safety, or, after one more confirming click, continue for 10 minutes.
- Medium-risk sites get a toolbar badge, a notification and a banner instead.

Extra tools in the popup
- Check how old a domain is (brand-new domains are a classic phishing sign).
- Look a site up on VirusTotal, or an IP address on AbuseIPDB.
- Report a phishing page.
- Mark a site you trust. (A trusted site that is on the threat list is still flagged.)

You are in control
In Options you can change how sensitive it is, switch notifications and the full-page warning on or off, protect your own domain name against lookalikes, and manage trusted sites.

Privacy in one paragraph
Septimius reads page text on your own device only, to look for scam phrases. That text never leaves your device. The site name of each page you open is sent to the Septimius server to check the threat database. Lookups you start yourself (VirusTotal, domain age, reports) send what they need to do their job. There is no account, no advertising and no selling of data. The full privacy policy is on this page.

Good to know
- It can make mistakes. A warning based on warning signs, rather than a listed threat, can be wrong, which is why you can always continue.
- It is not a replacement for antivirus software or common sense.
- It works with free online services. The first check after a quiet period can take up to a minute while the server wakes up; your on-device checks still work in the meantime.
- Needs Firefox 140 or newer.