The Halon MTA provides the widest support for threat protection vendors. It effortlessly integrates with any threat intelligence feed or content filter engine thanks to its scripting language, and we have published several ready-made integrations in our module library. 

Our integrated package (available as VMs or cloud images) comes with several engines installed, and we just added Spamhaus DQS. It includes support for Spamhaus’ latest developments; the hash blocklist (HBL). It’s a form of anti-virus so that you can filter additional malicious content. Using the HBL in conjunction with IP and domain blocklists, you can secure catch rates of 99.71%* and false positives as low as 0%. You can trial it free for 30 days.

In short, the HBL is a list of cryptographic hashes used to block different elements of malicious email content e.g. a cryptowallet address. Each hash forms a unique string, creating a one-off identifier for that specific piece of content, without using any personally identifiable data. Spamhaus’ HBL includes listings of compromised email addresses, malware files, and crypto wallet addresses. The malware part of the HBL acts like a type of anti-virus protection for your email stream. Typically, to identify malicious email, Spamhaus would assess the sender’s IP and/ or domain reputation. When an email account is from an ESP, like Gmail or Outlook, listings aren’t always possible, otherwise multiple users would be blocked. However, using a hash means Spamhaus can associate malicious email emitting from a specific, compromised email address.

With pioneering collection and distribution methods, Spamhaus’ researchers and engineers hash malware files, listing them in under 20 seconds after detection. By querying the Spamhaus Malware HBL, the return codes will highlight:

1. If the file is malicious. Here, the file has been assessed by Spamhaus Malware Labs and confirmed as known malware. The return code will also provide the family of malware. 
2. Or, if the file is suspicious: it has been observed in spam, thereby making it suspicious, though its intent is not confirmed as malicious by Malware labs. Extreme caution should still be taken when handling this file.

Another piece of content used to catch nefarious activity, when IPs and domains can’t be associated with spam, are cryptowallets. Spammers often request payment in cryptocurrencies like Bitcoin and Dash, among others, when trying to extort money from victims. Spamhaus hashes these cryptowallet addresses.  This enables email administrators to easily block the well-known ‘sextortion’ emails. You know the ones…

“I’ve hacked your account. I’ve been watching you visit adult sites. I have made a recording of you from your webcam. Send me money via my Bitcoin address 1N6dubqFmnyQ2DWvi32ppVbc3kKMTYcGW or I’ll share the recording with your contacts”.

To trial the Spamhaus blocklists, including the HBL, sign up for the Spamhaus Data Query Service (DQS). After signing up for the 30-day free trial, you will receive a DQS key. Entering this into the Halon MTA interface will get you protection with IP, Domain, and Hash blocklists. If you are already subscribing to Spamhaus’ IP and domain data, the HBL is available to you free of charge; just tick the HBL box on your Halon interface, and the rest will be done for you!

*Accurate as of March 2021. See here for the latest independent statics by Virus Bulletin.