Tools

AVG ThreatLabs
http://www.avgthreatlabs.com/

Not sure if a website's safe? Look up any website - Check its reputation - See what others say

BrightCloud URL / IP Lookup
http://www.brightcloud.com/tools/url-ip-lookup.php

Presents historical reputation data about the website

Cisco Sender Base
http://www.senderbase.org/

Presents historical reputation data about the website

Comodo Web Inspector
http://app.webinspector.com/

Examines the URL in real-time

Cymon
https://cymon.io/

Presents data from various threat intel feeds

Deepviz
https://search.deepviz.com/

Offers historical threat intel data about IPs, domains, etc.

DMOZ
http://www.dmoz.org/

DMOZ is the largest, most comprehensive human-edited directory of the Web. It is constructed and maintained by a passionate, global community of volunteers editors. It was historically known as the Open Directory Project (ODP).

FortiGuard URL / IP Lookup
http://fortiguard.com/iprep

Displays the URL's history and category

F-Secure Sample Analysis System
https://analysis.f-secure.com/portal/login.html

Submit suspicious files or URLs to F-Secure Labs for analysis. Please note that you will not get a reply or scan results for samples submitted anonymously.

IBM X-Force Exchange
https://exchange.xforce.ibmcloud.com/

Search by Application Name, IP address, URL, Vulnerability, MD5...

IPVoid
http://ipvoid.com/

IPVoid is a free service used to scan an IP address through multiple DNS-based blacklists and IP reputation services, to facilitate the detection of IP addresses involved in malware incidents and spamming activities.

Is It Hacked
http://www.isithacked.com/

Will check to see if a site is cloaked to GoogleBot, has spammy links, funny redirects, or otherwise appears to be hacked. Works on Joomla, Drupal, WordPress, Magento, Prestashop, Laravel, Codeigniter, Symfony or any other backend technologies.

Is It Phishing
http://isitphishing.org/

Assesses the specified URL in real-time

Joe Sandbox URL Analyzer
https://www.url-analyzer.net/

Free Automated Malware Analysis - Url Analyzer

Junk Email Filter
http://www.junkemailfilter.com/

Front end spam filtering and virus blocking service for your existing email server.

Malware Domain List
http://www.malwaredomainlist.com/

Looks up recently-reported malicious websites

Malware URL
http://www.malwareurl.com/listing-urls.php

Check a suspicious web site or IP address against a database of known malicious websites

MxToolbox
http://mxtoolbox.com/blacklists.aspx

The blacklist check will test a mail server IP address or domain against over 100 DNS based email blacklists

Norton Safe Web
http://safeweb.norton.com/

Look up a site. Get our rating.

Open Threat Exchange
https://otx.alienvault.com/browse/pulses/

At the heart of Open Threat Exchange is the pulse, an investigation of an online threat. Pulses describe any type of online threat including malware, fraud campaigns, and even state sponsored hacking.
Pulses are comprised of indicators of compromise (or IoCs), which describe the infrastructure of that threat - including IPs, file hashes, e-mail addresses affiliated with the threat, etc.

PhishTank
http://www.phishtank.com/

Looks up the URL in its database of known phishing websites

Project Honey Pot
http://www.projecthoneypot.org/

Project Honey Pot is the first and only distributed system for identifying spammers and the spambots they use to scrape addresses from websites.

Reputation Authority
http://www.reputationauthority.org/

Has your reputation been compromised? Check your Domain/IP behavior score

Sucuri SiteCheck
https://sitecheck.sucuri.net/

Free Website Malware and Security Scanner

ThreatMiner
https://www.threatminer.org/

Search for Domains, IPs, MD5|SHA1|SHA256, email address or ssl, user-agent, AV Family, Filename, URI, Registry, and MUTEX

Trend Micro Site Safety Center
https://global.sitesafety.trendmicro.com/

One of the largest domain-reputation databases in the world

Unmask Parasites
http://www.unmaskparasites.com/security-report/

Scan a web page for hidden illicit content (invisible spam links, malicious scripts and redirects), in the Google Safe Browsing Site Status database

URL Query
http://urlquery.net/

A service for detecting and analyzing web-based malware. It provides detailed information about the activities a browser does while visiting a site and presents the information for further analysis

URLVoid
http://urlvoid.com/

URLVoid is a free service that analyzes a website through multiple blacklist engines and online reputation tools to facilitate the detection of fraudulent and malicious websites. This service helps you to identify websites involved in malware incidents, fraudulent activities and phishing websites.

Virus Total
https://www.virustotal.com/

VirusTotal is a free service that analyzes suspicious files and URLs and facilitates the quick detection of viruses, worms, trojans, and all kinds of malware.

vURL
https://vurldissect.co.uk/

This service is completely free and allows you to view the source code within a webpage without your having to visit the site itself. In addition to this, options have been provided to view all links within a page for those of you that wish to do so

Web of Trust (WOT)
https://www.mywot.com/

WOT is a free add-on for your browser. WOT displays a colored traffic light next to website links to show you which sites people trust for safe searching, surfing and shopping online: green for good, red for bad, and yellow as a warning to be cautious. The icons are shown in popular search engine results, social media, online email, shortened URL's, and lots of other sites.

Web Page Speed Test
http://www.dotcom-monitor.com/WebTools/website-speed-test.aspx

Instantly test your website speed in real browsers from 20 locations worldwide

WebPulse Site Review
https://sitereview.bluecoat.com/sitereview.jsp

Check the current URL categorization of a website in the WebPulse (BlueCoat) URL ratings database

Yandex Safe Site Search
http://yandex.com/infected?l10n=en&url=8.8.8.8

Follow the above link, change the IP and search Yandex.
Yandex is one of the largest internet companies in Europe, operating Russia's most popular search engine and its most visited website. According to LiveInternet, as of December 2013, Yandex generated 61.9% of all search traffic in Russia. Yandex also operate in Ukraine, Kazakhstan, Belarus and Turkey.

Zscaler Zulu URL Risk Analyzer
http://zulu.zscaler.com/

Examines a URL using real-time and historical techniques