What Is an Indicator of Compromise (IoC)?

An indicator of compromise, often known by the acronym IoC, is a marker left in a system that a breach or cybersecurity event has occurred or is currently in the process of happening. IoC data points toward what type of attack has happened and other factors that can aid in launching a swift security response.

How Do IoCs Work?
What Are the Most Common Types of IoCs?
Importance of Monitoring for IoCs
Create a Bulletproof Security Strategy with Perimeter 81

Once a security team has identified the type of attack that has occurred by looking at IoCs, they can then use other tools, like the MITRE Att&ck Framework, and their own knowledge to create a response that will be most effective in that exact situation.

How Do IoCs Work?

IoCs could span from something as small as the presence of a malicious IP address or as obvious as a malicious file that still exists in your system.

Every attack, by nature, leaves behind a trace that cybersecurity experts can follow. The more knowledge an expert possesses of common attacks and what they look like, the more precise they can be when diagnosing the type of attack that a business has suffered.

Typically, to find IoCs in the event that a team is suspicious about their own systems, they will first conduct a surface-level observation of each system. If one system or application is performing at a level much lower than the standard, that could be the first sign that an attack has happened.

Next, after locating suspicious activity, experts will then conduct analysis in an attempt to find more IoCs, such as certain attack signatures or clear signals that a potential threat has gained entry into a company’s systems.

What Are the Most Common Types of IoCs?

IoCs naturally evolve and change as the digital landscape of cyber threats progresses. The most common IoCs today are completely distinct from those of 20 years ago, due to how certain threats have morphed or become more or less common.

Here are the most common types of IoC that a business is likely to come across when conducting cybersecurity defense monitoring:

File-based IoCs: File-based IoCs are signs that a file has been tampered with. This could include malware infections or foreign scripts that exist in the file’s code.
Behavioral IoCs: Quickly becoming the most prominent form of IoC, behavioral signs like poor performance, strange traffic patterns, several rapid login attempts, and odd user-patching interactions could all point toward malicious activity.
Network-based IoCs: Network-based IoCs relate to any signals that recent network traffic was either unusual, directed to known malicious hosts, or involving IP addresses that have been marked as malicious. These are especially common with attacks like phishing scams.

Other IoCs are related to specific domains. For instance, metadata IoCs are changes in the metadata of a file, and host-based IoCs are changes executed from a host on your system.

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Importance of Monitoring for IoCs

Monitoring for IoCs, especially with automated tools, is a vital part of effective cybersecurity defense as it allows businesses to get the upper hand on launching a rapid response. Without looking for IoCs, a security breach and data loss could have happened without your company ever knowing, leaving the door open for repeat attacks and showing cybercriminals that your team doesn’t have a grasp on modern threat vectors.

Detecting IoCs in a timely fashion helps your business better understand the current security environment in which they exist. Equally, if IoCs regularly crop up in relation to one system or attack vector, then they’re a surefire sign that your business needs to invest in a more comprehensive security solution in that area.

IoCs can factor into any security strategy and represent a core part of regular monitoring and system observation.

Create a Bulletproof Security Strategy with Perimeter 81

Understanding the common types of IoCs that your business is likely to encounter is a good way to better understand the cyberthreat to your company as a whole. Quickly locating and identifying IoCs enables a swift and precise response, helping to fortify your security posture and keep your business safe.

There is no better way to enhance your security posture and reduce the number of threats that plague your company than by working with a premier security solution.

Partnering with Perimeter 81 offers your business a range of security solutions and tools to keep you safe and automate the process of detecting IoCs. Reach out today for your free demo.

FAQs

What is an indicator of compromise?

An IoC is any sign or signal that an attack on a company’s network, system, or applications has occurred. These signs allow cybersecurity teams to better understand what threat entered their systems, providing them with a faster pathway to responding and creating a solution.

What are the three types of IoCs?

While some cybersecurity professionals focus on three main types of IoC (file-based, network-based, and behavioral), there are actually many more than this. Other types include metadata IoCs, host-based IoCs, and artifact IoCs.

What is the advantage of detecting IoCs?

Detecting IoCs as early as possible allows businesses to launch precise cybersecurity defense strategies as quickly as possible. Speed is vital in cybersecurity situations, with a fast response limiting the damage that a cybercriminal could do to your systems or the quantity of data they could exfiltrate.

How do teams investigate IoCs?

The best way to discover IoCs and investigate them further is to use system and network monitoring tools. You could turn to typical tools like IDS (Intrusion Detection Systems) or look to event management systems to see whether there has been irregular behavior in your system recently.

What are the best practices when using IoCs?

There are several best practices when using IoCs, spanning from regularly checking your software manually to launching highly automated, systematic checks. Where possible, you should use an automated strategy to detect IoCs and then supplement this with regular manual checks, paying close attention to any threat vectors that have most recently emerged.

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