As a short URL service provider what safety checks I should follow on URLs to keep minimum risk on my users. For example someone should not use my service to short their hacking, spamming, phishing, etc type of links.
For example I can do domain whitelisting on my service so only trusted domain URLs can be short through my service. Like that what other safety checks I should follow before shorting any URLs.
As a URL Shortner (Service Provider) this safety checklist should be followed before shorting any URLs to keep the risk at minimum. Please note that safety on the internet can not be provided by following or using only one checklist or certain rules. We must try new things on own and learn new things day by day. This checklist is part of my research on the internet.
Domain or IP Whitelisting/Blacklisting - This is one of the best safety mechanism we can implement to allow shorting URLs from only trusted domains/IPs. And we can also block certain domains/IPs like malicious domains and IPs. Sometime blacklisting is easy to bypass but whitelisting is hard to bypass so whitelisting is recommended. However we can do both according to our need.
Domain/IP Reputation Check - We can also implement a mechanism to check Domain/IP reputation on global internet before shorting it. For example malicious IPs/Domains might have bad reputation on global internet database, we can simply block those address for shorting.
Reference :-
Check DNS Records (mxtoolbox) - MxToolbox supports global Internet operations by providing free, fast and accurate network diagnostic and lookup tools. MxToolbox provide a great list of tools including blacklisting of any ip/host, whois lookup etc.
Virus Total IP/Domain check - Virus Total is an online service that analyzes suspicious files and URLs to detect types of malware and malicious content using antivirus engines and website scanners.
HTTPS Protocol use - Before shorting any URLs we must verify that the URL contain proper SSL/TLS certificate and it contains HTTPS protocol. It is high chance that malicious sites/IPs will communicate through HTTP protocol. So, we must avoid shorting of HTTP hosts.
Disallow known shortened links - Some users try to over smart the security system by shorting the URLs multiple times. As a short link service provider we know the security risks behind short links. So we must avoid shorting of links that are already shorted by other services or even our service.
Compare URLs to list of known badware - There are lots of online database that provide list of suspected malicious IPs and domains. Use this database to prevent shorting of this hosts.
Reference:-
URL Filtering - We can implement some policies like firewall policies that blocks certain content. For example, spam, nudity, violence, weapons, drugs, hacking, etc.