Advanced persistent threats (APT): a guide for enterprises

Instead of searching for an immediate payday, APT actors focus on long-term goals like industrial espionage, political leverage, or the steady exfiltration of sensitive data. Because these attacks are human-led and highly targeted, they can bypass traditional security software that only looks for known patterns.

In this guide, we’ll break down how these sophisticated operations function, the stages of a typical APT lifecycle, and the practical steps your organization can take to spot a silent intruder before they can do permanent damage.

What is an advanced persistent threat (APT)?

If you want to get a real sense of the APT attack meaning, think of it less as a virus and more as a determined burglar who hasn't just broken into your house—they’ve moved into the crawl space, learned your schedule, and are slowly shipping your valuables out the back door, one small box at a time.

An advanced persistent threat is a targeted, multi-phase campaign in which an intruder gains access to a network and stays there, undetected, for as long as possible. While a standard hacker might use an automated script to find a vulnerable target, an APT actor has a specific victim in mind.

Breaking down the 3 pillars of the name helps clarify what are advanced persistent threats in a practical business context:

• Advanced. The attackers use a mix of "low and slow" tactics, combining social engineering with custom-coded malware or zero-day exploits. If one method fails, they have the resources to build a new one.

• Persistent. The goal is continuous access. If you find one piece of their malware and delete it, they usually have 3 other backdoors already established to ensure the APT attack continues uninterrupted.

• Threat. We are talking about coordinated, well-funded advanced persistent threat groups—often state-sponsored or high-level criminal syndicates. They have a specific objective, like monitoring a government’s internal communications.

The 5 stages of an APT lifecycle

An advanced persistent threat attack operates on a timeline that would bore a typical hacker to tears. These operations are built on a timeline of months or years, moving through a series of steps designed to bypass even the most expensive security layers.

Let’s break down what a typical APT attack looks like:

1. Reconnaissance: scouting the perimeter

First things first, the attackers need to know who they are dealing with. They’ll spend weeks researching your organization, mapping out your hierarchy, and identifying specific employees who might be a weak link. Usually, this culminates in a highly targeted spear-phishing email. All it takes is one person clicking a legitimate-looking link for the attackers to gain access and plant their first foothold.

2. Infiltration: breaking ground 

Once they’ve tricked their way past the front door, the real work begins. The attackers will install custom malware to establish a "backdoor"—a secret communication channel that connects your internal network to their private servers. At this point, the breach is still quiet. They aren't causing a ruckus because they don't want to trigger any alarms just yet.

3. Lateral movement: creeping through the hallways 

Now that they are inside, the attackers realize that the employee who clicked the link probably doesn't have the keys to the figurative main door. Consequently, they begin moving sideways through the network. They’ll jump from one computer to another, harvesting credentials and escalating their privileges until they find the high-value servers—the ones holding your intellectual property, financial records, or customer data.

4. Exfiltration: the silent heist 

After identifying the most valuable assets, the group begins "mailing" the stolen data back to themselves. However, they don't do this in one giant file transfer, as that would be too easy to spot. Instead, they’ll break the data into tiny chunks and send them out slowly, often disguised as normal, everyday network traffic, to ensure the APT attack remains invisible.

5. Persistence: digging in for the long haul 

Even after they’ve gotten what they came for, they rarely just leave. To ensure they can return whenever they please, they’ll scrub their logs to hide any evidence of the intrusion and plant multiple "sleeper" backdoors throughout the system. This allows advanced persistent threat groups to lie low for months, only to wake up and strike again the moment you have something new worth stealing.

Who are the typical perpetrators of an APT?

Executing an advanced persistent threat attack requires an enormous amount of capital, technical expertise, and, most importantly, time. Because of these high entry barriers, you won't usually find a lone-wolf hacker behind these campaigns. Instead, these operations are almost always the work of organized, professional groups with very specific agendas.

When we look at the actors behind an advanced persistent threat, they generally fall into a few distinct categories:

• State-sponsored groups. These are the most common and well-funded perpetrators. Intelligence agencies or military units often back these groups to conduct espionage, steal state secrets, or disrupt the infrastructure of a rival nation. For these actors, the goal is long-term geopolitical advantage rather than a quick payday.

• Criminal syndicates. High-level criminal organizations have started adopting APT tactics. They might spend months inside a financial institution’s network to eventually facilitate a massive, multi-million dollar heist or steal intellectual property they can sell to the highest bidder on the dark web.

• Hacktivists. Occasionally, groups driven by political or social ideologies will use APT methods to gain access to corporations or government entities. Their goal is usually to leak sensitive documents, to embarrass their target, or to cause enough reputational damage to force a change in policy.

• State-affiliated "contractors". In some regions, the line between government work and private crime is blurred. These are private groups that are protected (or even funded) by a government to carry out attacks against foreign targets, often combining state-level resources with the agility of a private startup.

How to protect your organization against APT attacks?

Protecting your business from an APT attack is about making life as difficult and expensive as possible for the intruder. You want to turn your network into a place where they can’t move an inch without sounding an alarm.

Here is how you build a defense that actually stands a chance:

Full visibility: light up the dark corners 

You can't stop what you can't see. Most APT cybersecurity failures happen because attackers find a blind spot—like an old, forgotten server or an unmanaged employee device—and use it as their base of operations. You need a total, real-time map of every device, user, and data flow in your organization. If you know exactly what the "normal" looks like, the "weird" stuff starts to stand out pretty quickly.

Proactive hunting: don't wait for the alarm 

Automated alerts are great, but they aren't perfect. Advanced attackers spend their lives figuring out how to stay just below the threshold of an automated red flag. This is where human-led threat hunting comes in. Think of it as having a security team that assumes you've already been breached and spends its day actively looking for the tiny, quiet footprints an intruder leaves behind.

Advanced tools: your digital "security cameras" 

You need specialized gear to catch specialized threats. This means deploying endpoint detection and response (EDR), which acts like a flight data recorder for every laptop and server, and web application firewalls (WAF) to scrub the traffic coming into your public-facing sites. These tools look for suspicious behavior, like an HR computer suddenly trying to talk to a financial database at 3:00 AM.

Intelligence: know your enemy 

If you know which advanced persistent threat groups typically target your industry, you can anticipate their moves. By using global threat intelligence, you can feed your systems with "digital fingerprints" of known attackers. It’s a lot easier to spot a burglar if you already have a photo of their face and know they usually come in through the basement window.

Speed: the "18-minute" rule 

In modern cyberattacks, once an intruder gets in, they can start moving to your most sensitive systems in under 18 minutes. Speed is everything. Your goal shouldn't just be detection, but rapid detection. The faster you can isolate a compromised computer, the less likely it is that a small breach turns into a company-wide disaster.

Advanced persistent threat examples

Some of the biggest advanced persistent threats were years-long projects, attesting to the complexity of such attacks. Some APT groups have been around for over a decade, targeting high-profile subjects and companies, often in politically charged schemes. Many such groups are considered state-sponsored, while others may form on their own volition.

One of the oldest named attacks is Titan Rain, which started in 2003 and lasted several years. While the attacks that targeted the computer systems of various US-based organizations originated in China, the specific group was never identified or named. Nevertheless, the APT space is associated with a few notorious groups associated with cyber espionage, warfare, and hacktivism.

The APT group names that you see in the news are rarely official. Unlike other cybercrime groups that may pick a moniker, APT groups are identified and named by cybersecurity and cyberintelligence agencies. Therefore, you may see the same group referred to by a different name. For example, Microsoft’s naming taxonomy assigns climate terms based on the presumed region of the attack, whereas CrowdStrike uses animal names, i.e., “Typhoon” and “Panda” for China or “Sandstorm” and “Kitten” for Iran, respectively.

Fancy Bear (Forest Blizzard, APT28)

Fancy Bear is a Russian-based cyber espionage group. Although it wasn’t officially identified until 2014, it’s been engaged in advanced persistent threat attacks since at least 2007. The primary exploitation used by APT28 is zero-day vulnerabilities. Over the years, the group has been associated with Russian military intelligence and has been part of active cyber warfare following Russia’s invasion of Ukraine in 2022. They’ve also notably targeted the German parliament in a six-month APT in 2014 and interfered in presidential elections in France and the US.

Lazarus (Diamond Sleet, APT38)

Lazarus is an allegedly North Korean cyber warfare group. Its earliest confirmed APT attack, Operation Troy, dates back to 2009 and lasted until 2012. The group targeted the South Korean government with a stream of DDoS attacks. In recent years, Lazarus gained more notoriety for attacks against cryptocurrency exchanges, digital casinos, and traditional financial institutions.

Helix Kitten (Hazel Sandstorm, APT34)

Helix Kitten is assumed to be an Iranian cybercriminal group. It has a history of targeting financial and telecommunications industries, particularly in the Middle East, and relies heavily on social engineering techniques in its attacks. Its targets often overlap with those hit by Refined Kitten, another APT group assumed to be from Iran. However, it’s unclear whether the two groups work in tandem.

How can NordPass help you stay protected? 

Perhaps the scariest thing about advanced persistent threats is their ability to infiltrate a system undetected. This simply means that you need to reinforce your first line of defense to prevent cybercriminals from breaching your systems in the first place. Even if you suspect you’re under attack, you can work on reinforcing your APT cybersecurity protection.

You may have noticed a trend already – many APT attacks involve social engineering techniques and rely on human error to succeed in the early stages. This makes protective measures surprisingly easy – implementing a secure password management system in your organization can be a life-changer.

The NordPass Enterprise password manager lets you set up a robust company-wide password policy, ensuring everyone adheres to the highest security standards. The Enterprise plan is compatible with major identity authentication services, enabling secure and instant single sign-on (SSO) access. If you suspect any malicious activity from within, you can easily revoke access to sensitive information or reassign it to a different employee. If you suspect that your sensitive data has been compromised, you can use the Data Breach Scanner to track your company credentials, domains, and credit card information.

Get in touch with our team to learn more about how NordPass helps your organization stay secure in the face of advanced persistent threats.