What are indicators of compromise (IoC)?

Indicators of compromise (IoC) are evidence left behind by an attacker or malicious software that can be used to identify a security incident.

Learning Objectives

After reading this article you will be able to:

  • Define indicators of compromise (IoC)
  • Highlight common IoCs
  • Learn how to use IoCs to improve detection and response

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What are indicators of compromise (IoC)?

Indicators of compromise (IoCs) are information about a specific security breach that can help security teams determine if an attack has taken place. This data can include details about the attack, such as the type of malware used, the IP addresses involved, and other technical details.

How do indicators of compromise (IoC) work?

Indicators of compromise (IoC) help organizations locate and confirm the presence of malicious software on a device or network. Attacks leave behind traces of evidence, such as metadata. The evidence can be used by security experts to detect, look into, and address security incidents.

IoCs can be obtained through several methods, including:

  • Observation: watching for abnormal activity or behavior in systems or devices
  • Analysis: determining the characteristics of the suspicious activity and analyzing its impact
  • Signatures: identifying known malicious software signatures

What are the common types of IoCs?

There are several different types of IoC that can be used to detect security incidents. They include:

  • Network-based IoCs, such as malicious IP addresses, domains, or URLs can also include network traffic patterns, unusual port activity, network connections to known malicious hosts, or data exfiltration patterns.
  • Host-based IoCs are related to activity on a workstation or server. File names or hashes, registry keys, or suspicious processes executing on the host are examples of host-based IoCs.
  • File-based IoCs include malicious files like malware or scripts.
  • Behavioral IoCs cover several types of suspicious behavior, including odd user behavior, login patterns, network traffic patterns and authentication attempts.
  • Metadata IoCs have to do with the metadata associated with a file or document, such as the author, creation date, or version details.

Indicators of compromise vs. indicators of attack

IoCs resemble indicators of attack (IoA), however, they differ slightly. IoAs focus on the likelihood that an action or event may pose as a threat.

For example, an IoA indicates that a known threat group has a high probability of launching a distributed denial-of-service (DDOS) attack against a website. In this situation, an IoC might show that someone has gained access to the system or network and transferred a large amount of data.

Security teams frequently use both IoAs and IoCs to identify attacker behavior. For another example, an IoC identifies unusually high network traffic, while the IoA is the prediction that the high network traffic may indicate a upcoming DDoS attack. Both indicators help provide important insight into potential threats and vulnerabilities in networks and systems.

Indicators of compromise best practices

Indicators of compromise (IoC) best practices covers several techniques, including using both automated and manual tools to monitor, detect, and analyze evidence of cyber attacks.

As new technologies and attack vectors emerge, it is incredibly important to regularly update IoC procedures. By staying up-to-date on IoC procedures and best practices, organizations can stay ahead of the threat landscape and protect themselves from malicious activity.

Cloudforce One

Cloudforce One is a threat operations and research team created to track and disrupt threat actors. The team’s advanced threat intelligence capabilities allow a comprehensive coverage of all entities in the threat landscape and help organizations take action before any threats can cause damage.