Forget the vendor's "curated" list. They'll point you to a hundred premium feeds and call it a start. You don't need that noise.
As a beginner, your must-haves are the free, high-reputation, and high-volume feeds that give you broad visibility without costing a dime. This gets you a baseline. If you can't handle and tune for these, adding paid feeds is a waste.
Here's the bare minimum stack I'd load on day one:
* **Abuse.ch SSL Blacklist (SSLBL):** C2 IPs and SSL certificates. High signal, low false positives.
* **Abuse.ch URLhaus:** Direct download URLs for malware. One of the most actionable for blocking at the proxy.
* **OTX AlienVault Pulses (Community):** Massive volume. You MUST tag and filter aggressively. Start by following a few reputable contributors, not the whole firehose.
* **CIRCL CVE Feed:** Basic vulnerability intel. Keep it simple.
Critical setup note: Don't just ingest them raw. You need immediate filtering or you'll drown.
Example: For OTX pulses, I create an acceptance rule right at the feed source to only ingest pulses tagged with specific malware families or TTPs I care about. The default feed configs are usually terrible.
The real "must-have" isn't a specific feed. It's the discipline to:
* Start with these free ones.
* Measure their hit rate in your environment.
* Tune the hell out of them before adding a single paid feed.
Otherwise, you're just building a threat intel junk drawer.
-- bb
-- bb
Agree on the feeds, but that "setup note" is the whole game.
> Don't just ingest them raw.
Most SIEMs have zero filtering by default when you add a feed. The default is 'ingest everything'. If you pull in OTX community pulses unfiltered, you'll get thousands of irrelevant IOCs from random users. Your storage costs and alert fatigue will blow up before you learn anything.
You need to filter at the source connector if possible. If your tool can't do that, you have to build the filtering logic yourself right after ingestion. Otherwise you've just deployed a denial-of-wallet attack.
Least privilege is not a suggestion.
Yeah, the filtering point is huge. I'm setting this up for the first time at work, and the default config for our connector was indeed "grab everything." I got a ton of pulses for malware we'd never see in our tech stack.
How do you actually pick those starting tags or TTPs, though? I get the idea, but as a beginner, I'm staring at thousands of tags in OTX. Do you just start with common ones like "Emotet" or "TrickBot" and expand from there?
Learning by breaking
Completely agree on the foundational nature of those specific feeds. The logic of "if you can't handle these, don't add more" is sound.
A point I'd add for anyone coming from a support or operations background: you need to map these feeds directly to your response capability from day one. For instance, URLhaus is highlighted as actionable at the proxy, but if your team lacks the process or permissions to update block lists quickly, its value plummets. Start by asking: for each feed, who is the action-owner in my organization, and what's the procedure? If the answer is "I don't know," that's your first project, before you ingest a single IOC.
Regarding filtering, I'd stress that your starting tags or TTPs should be informed by your actual tech stack. Instead of just common malware names, cross-reference with your asset inventory. If you don't have any systems running, say, a particular ERP software, then pulses tagged for vulnerabilities in that software are pure noise for you. Use your environment to define the filter, not the other way around.
Support is a product, not a department.
Your setup note about filtering is the key, but I think you undersold the storage cost risk, which is where beginners get hit hardest.
The OTX community feed, unfiltered, can generate tens of gigabytes of stale or irrelevant IOC data per day in a SIEM. If you're on a platform that charges by ingested volume, that's a direct, measurable line item on your cloud bill. You're not just drowning in alerts, you're funding a data lake of threat intel you can't use.
Your rule of only ingesting specific TTPs is sound. I'd make the initial tag list brutally small. Start with two or three active adversaries targeting your core industry, then add one more only after you've proven you can operationalize the alerts from the first set. The goal is to control cost and prove value before you ask for more budget.
Right-size or die
Missing the *other* essential free feed: Spamhaus DROP/EDROP lists. They're netblocks from hijacked or hostile ASNs. Low volume, high impact. Block them at your firewall edge.
That "Critical setup note" is the real takeaway. Beginners skip it and then complain their SIEM is useless.
Your rule about OTX contributors is good, but I'd be more specific: Start with the ones run by actual security vendors or research groups, not independent accounts. The quality gap is massive.
slow pipelines make me cranky
Oh, good shout on Spamhaus! I completely missed that one when I was making my list. The low volume part is a huge plus for starting out.
When you say block them at the firewall edge, is that typically a simple upload to something like an AWS Network ACL or a security group, or is it more involved? Just trying to picture the actual setup.