What is an Advanced Persistent Threat (APT)?

APTs are categorized based on various criteria, from their origin and methods to the methods of infiltration or geographical focus.

While there is no perfect set of characteristics to define every Advanced Persistent Threat, the categories of APTs most commonly encountered and discussed are as follows:

·       Nation-state APTs: With enormous budgets and access to the latest technology, along with legal cover, these threat actors carry out some of the most sophisticated missions. These include long-term espionage, data theft, public opinion manipulation, etc. They have well-established political or military objectives and target government organizations, military installations, key infrastructure, economic players, and essentially anyone or anything that can aid them in achieving their long-term goals.

·       Criminal APTs: Some groups engaging in APT activities focus on stealing money or other valuable data such as intellectual property or compromising data for blackmail or extortion. Often, the final objective of these threat actors is deploying ransomware in high-value networks, committing banking fraud, stealing, and selling credit card information, or even mining cryptocurrency illegally using victims’ infrastructure.

·       Hacktivist APTs: Some groups use their cyber capabilities to push political agendas, drive social change, or promote ideologies through targeted attacks aimed at shutting down critics, spreading propaganda, or destroying opposition. Their tactics include Distributed Denial of Service (DDoS) attacks, website defacements, and leaking sensitive information. These groups seek publicity, often expressed through manifestos or public messages.

·       Corporate/Business APTs: Employed or sponsored by business organizations, these APTs spy on competitors, usually at the large corporation level. With the emergence of APT-as-a-service, skilled cybercriminal groups now offer their services for industrial espionage. Threat actors in this category are motivated by gaining a competitive advantage, financial gain, or obtaining valuable information for corporate espionage.

1.       Infiltration – Gain a Foothold: In the first stage, attackers exploit vulnerabilities or employ social engineering techniques to gain unauthorized access. Methods range from exploiting zero-day vulnerabilities or network weaknesses to spear phishing targeting key individuals in the organization. The objective is to establish a discreet point of entry, setting the stage for the attack.

2.       Expansion – Explore to Establish Persistence: After a successful initial infiltration, attackers move laterally across the network to expand their control and deepen their access. They typically seek accounts with elevated privileges for better access to critical systems and sensitive data. Attackers may use malware to establish a network of backdoors and tunnels, making it easier to move undetected within the system. The attackers' efforts are directed toward entrenching themselves in a position better suited to achieve their primary objectives.

3.       Extraction – Make Your Getaway, Often: In this phase, the attackers already have an understanding of the system vulnerabilities and way of work. This familiarity allows them to harvest the needed information and perhaps store it in a secure location within the network. To avoid detection during the extraction, threat actors use distractions such as DDoS (Distributed Denial-of-Service) attacks.

In some cases, getting information is not the final goal and the APT. Instead, resources are geared towards undermining an important project, mission, or program of the targeted organization.

Regardless of the goal, actors consistently try to cover their tracks to maintain undetected access to the network for further attacks.

Detecting an Advanced Persistent Threat requires a comprehensive security strategy that encompasses threat hunting across processes, workloads, and platforms, meticulous monitoring throughout the environment, and the analysis of both inbound and outbound network traffic. Cybersecurity teams must be adept at recognizing the subtle “signals” of APT activity, such as command and control traffic patterns. These weak indicators must be assembled into a consolidated threat analysis that can be quickly accessed and acted upon by a human. Without this, teams may struggle to implement a timely and effective response.

Upon detection, the response should be immediate and focused. The goal is to identify affected systems, remove backdoors, and prevent lateral movements. Organizations must also invest time and effort in meticulous post-incident analysis to fortify defenses against future attacks. Analyzing both the technical aspects of the breach and the operational procedures is fundamental to reducing the organization's risk profile.

There are best practices an organization can follow to reduce security vulnerabilities commonly exploited by APTs, such as, but not limited to:

·       Reducing the attack surface with regular updates and patching of software, applications, and devices.

·       Implementing comprehensive monitoring of network traffic, applications, and domains, as well as robust access control measures, including two-factor authentication, to secure key network access points..

·       Encrypting all remote connections.

·       Inspecting incoming emails to mitigate the risks associated with spear-phishing.

·       Analyzing and logging security events immediately to facilitate rapid threat identification and response.

At the most basic level, regular training can significantly reduce the risk posed by human factors. Human error is often the weakest link in cybersecurity, and APTs frequently exploit this through social engineering techniques. Having a formalized and practiced incident response plan in place will enable effective and coordinated action during a security breach.

Advanced Persistent Threats (APTs) constantly evolve, posing a real challenge for security teams. This evolution challenges their ability to track, mitigate threats, and be resilient against their impact. Security teams can detect and respond to advanced threats by using the MITRE ATT&CK Framework, a global knowledge base of adversary tactics and techniques.

Budget limitations and a persistent shortage of skilled professionals leave Security Operations Centers (SOCs), Managed Security Services Providers (MSSPs), and in-house security teams without the necessary resources. The ongoing rise in sophisticated cyber-attacks has led to an increase in security teams integrating data from standard detection tools with actionable threat intelligence.

Threat intelligence, when paired with Endpoint Detection and Response (EDR) systems, becomes a powerful ally. Extending EDR to include feeds and creating Extended Detection and Response (XDR) helps organizations leverage visibility over all network assets and devices to detect potential entry points for APTs.

Deep log analysis by a team cannot distinguish malicious activity from legitimate activity in real-time. Therefore, a good cyber defense is an intelligent, automated cyber defense solution that leverages cyber threat intelligence and advanced defense mechanisms for adversary pursuit.

Many organizations partner with cybersecurity companies for advanced defense strategies, deploying sensors, utilizing threat intelligence, indicators of compromise (IOCs), and Web Application Firewalls (WAFs). These partnerships are vital for providing human-readable outcomes to threat hunting, aimed at proactively searching for indicators of APT activities within an organization’s multi- or hybrid-cloud footprint.