According to Crowdstrike, a leader in cybersecurity, "indicators of attack (IOAs) are telltale signs or activities that signal a potential cybersecurity threat or attack is in progress. Traditional security measures are often reactive, focusing on the aftermath of an attack. IOAs, on the other hand, are proactive, and they're a vital part of the early stages of threat detection. They aim to identify and mitigate a threat before it can fully materialize."
The healthcare industry has increasingly become a primary target for cybercriminals, largely due to the abundance of sensitive patient data it manages and the nature of its operations. In 2023 alone, the healthcare sector reported data breaches costing an average of $10.93 million per incident — nearly double the average cost seen in the financial industry, which ranked second at $5.9 million. These cyberattacks jeopardize patient safety and pose substantial risks to the stability and integrity of entire healthcare organizations.
Understanding IOAs
IOAs are a component of cybersecurity strategies to identify and mitigate potential threats. Unlike indicators of compromise (IOCs), which focus on evidence that a cyber incident has occurred, IOAs provide insights into the intentions and techniques employed by threat actors during an attack.
When analyzing IOAs, the specific cyber threats, such as malware or ransomware, are of lesser concern. Instead, the focus is on understanding the sequence of events leading to deploying a cyber threat. By deciphering the motivations and objectives behind each stage of an attack, organizations can develop effective strategies to prevent or mitigate future incidents.
Read more: What are indicators of compromise?
Examples of indicators of attacks
To gain a better understanding of IOAs, here are some examples of common IOAs based on cybercriminal behavior:
Public servers communicating with internal hosts
One indicator of an attack is the communication between public servers and internal hosts. This activity may indicate data exfiltration or remote communication from criminal servers. Monitoring such communication patterns can help organizations identify potential breaches and take proactive measures to prevent further compromise.
Connections via non-standard ports
Unusual connections made via non-standard ports rather than commonly used ports can indicate suspicious activity. Cybercriminals often employ non-standard ports to bypass traditional security measures.
Internal hosts communicating with countries outside of business range
Communications between internal hosts and countries outside the organization's usual business range can raise suspicion. Such activity may indicate unauthorized data exfiltration, unauthorized access attempts, or compromised systems.
Inter-host communications within short time periods
Unusually frequent inter-host communications within short periods can signal lateral movement by cybercriminals. This activity may indicate attempts to spread laterally across the network or coordinate attacks between compromised systems.
Multiple honeytoken alerts from a single host
Honeytokens are decoy assets placed within an organization's network to attract attackers. Multiple alerts triggered by a single host, especially outside of business hours, can indicate unauthorized access attempts or compromised systems.
Excessive SMTP traffic
Unusually high volumes of Simple Mail Transfer Protocol (SMTP) traffic can indicate suspicious activity. This may suggest that a compromised system is being used to launch distributed denial-of-service (DDoS) attacks or send spam emails.
Malware reinfection within a few minutes of removal
Reinfection by malware shortly after removal can indicate the presence of advanced persistent threats (APTs). APTs are sophisticated attacks that often involve persistent access to compromised systems.
Multiple user logins from different regions
Multiple user logins from different regions, especially within a short time period, can indicate stolen user credentials or unauthorized access attempts.
Read more: What is data exfiltration in cybersecurity?
The future of cybersecurity
Group-IB, a leading innovator in cybersecurity technologies, advocates for the synergy of IOAs and IOCs as a unified strategy for decoding and mitigating cyberattacks. Continual monitoring and analysis of IoAs and IoCs are necessary for organizations to cultivate a proactive and adaptive cybersecurity posture.
This integrated approach reduces the potential impact of cyberattacks and fortifies defenses. By combining IoAs, which discern user intent from network interactions pre-attack, with IoCs, which provide evidence of compromised network security, organizations establish a formidable defense mechanism.
Advantages of this combined approach include early detection, where IoAs serve as an early warning system, and confirmation through IoCs, enhancing threat detection accuracy according to Group-IB. Additionally, the synergy between IoAs and IoCs offers a comprehensive defense strategy, enabling adaptability to evolving threats, efficient incident response, and continuous monitoring and upgrading to defend against cyber threats proactively.
FAQs
What is the difference between IOAs and IOCs?
IOAs focus on the intentions behind each stage of a cyberattack, providing insights into attacker motivations. On the other hand, IOCs are evidence that a cyber incident has occurred, helping identify past attacks.
How are IOAs detected before data breaches?
IOAs are detected by monitoring and analyzing indicators of suspicious activity, such as unusual communication patterns, inter-host communications within short time periods, and connections via non-standard ports.
Can IOCs detect emerging threats?
IOCs rely on predefined signatures or patterns associated with known threats, making them less effective in detecting emerging threats like zero-day exploits.
What are the limitations of IOC-based detection mechanisms?
IOC-based solutions may struggle to detect emerging threats and have predictable scanning schedules that can be exploited by attackers.
How can organizations make use of IOAs and IOCs together?
By combining IOAs and IOCs, organizations can develop more comprehensive and proactive cybersecurity programs, using the strengths of each approach to overcome their specific limitations.
See also: HIPAA Compliant Email: The Definitive Guide
Farah Amod
