IoCs-detox: protecting TI from false indicators

IoCs-detox: protecting TI from false indicators ✋

Imagine this: your SOC team receives a fresh feed of compromise indicators. The list contains hundreds of new IP addresses, hashes, and domains. You load them into your security system, and… chaos ensues. False positives pour in like a cornucopia, legitimate traffic gets blocked, and real threats get lost in the noise 🤯

Why are false indicators a serious problem? At first, infosec analysts react vigorously to each new indicator. But after dozens of false positives, “alert fatigue” sets in — and then a real threat goes unnoticed. Moreover, this creates a bad reputation for feeds in general, as analysts begin to believe they cause more harm than good.

🤔 Where do false indicators come from?

• Analyst errors. The human factor is always present. A typo in a report can turn a legitimate IP address into a malicious one.

• Outdated data. An indicator may have been relevant a year ago, but now belongs to a completely harmless service.

• Hasty conclusions. Some researchers inflate their reports by adding unverified data.

• Contextual errors. An IP address may be considered malicious in one campaign but perfectly normal in the context of other activity.

• Decoys. Some attackers deliberately “plant” false indicators to mask real malicious activity and discredit specific TI providers.

😎 How to protect against false indicators?

1️⃣ Best practice is not to trust a single source. Cross-check every suspicious indicator against at least three or four authoritative threat databases or feeds from other TI providers.

2️⃣ Trust only verified TI data vendors with a good reputation. Implementing a TI vendor quality assessment system, which we discussed earlier, is especially helpful here.

3️⃣ Before taking any action on security events related to a compromise indicator, its context can be subjected to additional analysis. For example, if the context is empty and there is just a statement that the indicator is malicious, it is better to either filter it out or put it under monitoring. If there are clear links to group activity, techniques used, and connections to other dangerous indicators, then such activity can be blocked.

4️⃣ A new iteration of feeds or a batch of new indicators should preferably be considered only in monitoring mode for at least a few hours initially. Observe their activity before adding them to blocking rules.

5️⃣ For blocking rules based on compromise indicators, consider checking for security events from other types of security tools.

Cybercriminals are well aware of the problem of false IoCs and actively exploit it. Proper indicator filtering is not just a convenience, but a necessity for effective protection.

#TI #ioc #tips
@ptescalator