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Prioritize Indicators of Compromise: Investigate the Flaming Critical Indicator First!

Threat intelligence plays a crucial role in helping analysts identify and investigate high-risk activities. 

Threat intelligence solutions work primarily by identifying known Indicators of Compromise (IOCs) in systems and networks. These indicators allow information security analysts to detect malicious activities and identify the specific attack framework they adhere to. 

Without this valuable data, linking suspicious behaviors to a specific type of cyberattack is challenging and prone to error. Cybercriminals rarely announce themselves until after they’ve compromised their victims’ systems, when it’s too late for anyone to stop them. 

Equipped with the right threat intelligence software, security information and event management (SIEM) platforms can provide valuable context into suspicious activities and behaviors. This gives analysts the all-important ability to tell the difference between an urgent, all-hands-on-deck attack scenario and a far less dangerous one. 

What Kind of Data Do IOCs Contain? 

Just as the name suggests, indicators of compromise show specific network events or changes that suggest known malicious behavior. They correlate these activities to specific threat actors and attack signatures so that analysts can immediately tell “who” is likely responsible for the attack in question and what their next steps might be. 

For example, on March 9th, 2022, CISA published updated information about the specific IP addresses Conti ransomware actors use to communicate with their command and control server, along with a list of URLs associated with the group. This tells threat intelligence platforms that any connection to one of those addresses or URLs is probably linked to a Conti ransomware attack. 

A security analyst with experience responding to these types of attacks will know what typically follows this step in the cyberattack kill chain. This gives them a valuable advantage – the ability to outmaneuver the threat actor before the attack is complete. 


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Individual IOCs may contain a variety of data types and correlations. Many indicators of compromise involve one of the following activities or changes: 

  • Unusual DNS lookup activity 
  • Connections to known botnets or malware C&C servers 
  • Excessive access volume to one file 
  • Suspicious administrator or privileged user activity  
  • Unexpected software updates 
  • Data transfer over rarely used ports 
  • Obviously non-human behavior on human user accounts. 
  • An attack signature or a file hash of a known piece of malware 
  • HTML responses of an unusual size 
  • Unusual changes to configuration files, registers, or device settings 
  • Multiple unsuccessful login attempts 

Which IOCs Are the Most Important? 

The short answer is it depends on your individual security posture. 

There is no such thing as a one-size-fits-all threat intelligence analysis. Some threats represent a more severe risk to your organization than others. Your particular security posture might mean addressing one type of threat is a piece of cake. For another organization, that same threat could represent a catastrophic risk. 

This is why generic threat intelligence data supplied with your SIEM can’t draw your attention to the urgent, high-impact threat indicators you need to see first. It doesn’t know anything about your organization’s security posture, so it can’t prioritize IOCs effectively on its own. 

Threat intelligence solutions like Anomali ThreatStream offer access to a curated list of the most urgent indicators of compromise impacting your environment. This information will help your security team distinguish between urgent attack scenarios and lower-impact threats that you can safely take time to investigate and resolve.  

Get Proactive About Threat Hunting 

Castra’s security operations center staff can help you implement active threat intelligence into your security posture so that your organization is prepared to meet security challenges head-on. Using Anomali ThreatStream, our analysts can reduce false positives and accurately assess the severity of threats according to your unique risk profile.

 

Make active threat hunting part of your security posture with our help. Get in touch today.