What is an Advanced Persistent Threat (APT)?

An Advanced Persistent Threat (APT) is a sophisticated cyberattack in which attackers quietly enter and remain hidden inside a network for an extended period, carefully avoiding detection.

APTs focus on secretly stealing sensitive information, such as intellectual property, financial data, or government secrets.

The attackers typically gain access, establish hidden control, and patiently extract valuable data over weeks, months, or even years.

Consequences of APT Attacks

The consequences of APTs are unpredictable, and the financial damage cannot be correctly estimated. An example is the successful embezzlement of 81 million USD from the Central Bank of Bangladesh (Lazarus, 2016).

APT attacks can affect all organizations – government, military, financial, information technology companies, media, etc. Governments also sponsor several APT campaigns (we classify such attacks as nation-state).

Here are the main consequences of APT attacks:

  • Sensitive information, such as military secrets, weapons, and attack plans can be stolen.
  • Your reputation takes a hit, making customers and business partners question whether they can still trust you.
  • Financial setbacks, including the costs of cleanup, regulatory fines, and potential lost business.
  • Legal headaches, as losing sensitive data, can land you in trouble with laws like GDPR and HIPAA.
  • Operations slow down or shut down because your team needs time to investigate, fix damage, and get everything running again.
  • Competitors gain an advantage, as stolen trade secrets or strategies could fall into the wrong hands.
  • Risk of ongoing attacks, because attackers often leave hidden doors to return and cause more harm.
  • Loss of confidence, leading to lower employee morale and investor concerns about security and management.

Advanced Persistent Threat Progressions

Advanced Persistent Threats differ significantly from typical cyberattacks. Rather than aiming for immediate disruption, APT attackers patiently and methodically work through networks over extended periods, often weeks or months. Their primary goal is quietly accessing and extracting sensitive information without raising suspicion.

APTs generally progress through three distinct stages:

Stage 1: Infiltration

In the first stage, attackers quietly enter the targeted organization’s network. Typically, infiltration occurs through vulnerabilities in one or more of these three areas:

  • Web assets: Exploiting software vulnerabilities via attacks like Remote File Inclusion (RFI), SQL injection, or cross-site scripting (XSS).
  • Network resources: Identifying and leveraging misconfigured or unsecured servers and network devices.
  • Authorized users (social engineering): Using techniques such as spear phishing to trick employees into revealing credentials or downloading malicious files.

Once inside, attackers install hidden “backdoor” malware, providing continuous access even if the initial breach point is detected and fixed. This malware often masquerades as legitimate software to remain unnoticed.

Stage 2: Expansion

With initial access secured, attackers carefully expand their reach within the organization’s network. Their goal at this stage is to target high-value individuals, often executives, system administrators, or staff with privileged access to confidential information.

As it moves laterally through the network and gains higher privileges, attackers gather sensitive data such as product designs, employee records, financial details, or strategic business plans.

Depending on their ultimate objective, attackers might:

  • Alter or sabotage data: Subtle manipulations to product designs, financial reports, or business plans can significantly harm business operations.
  • Prepare for large-scale disruption: Gaining control over critical systems allows attackers to create coordinated disruptions, such as database deletions, communication shutdowns, or operational sabotage, designed to cause extensive and prolonged damage.

Stage 3: Extraction

In the final stage, attackers focus on securely extracting stolen information from the network. Typically, sensitive data is initially stored temporarily within the compromised network. This is hidden from sight until attackers determine it’s safe to move out without detection.

To mask the data extraction, attackers frequently utilize distraction techniques. Another DDoS attack, for example, creates “white noise,” distracting security teams and saturating network defenses.

Notable APT Campaigns and Threat Actor Groups

Below are some of the most researched and actively tracked APT groups, with detailed analysis from Group-IB:

1. Lazarus Group

Known for: Espionage, financial theft, and disruptive attacks
Group-IB’s investigations into Lazarus reveal its stealthy attack chains and advanced tooling, including Python scripts used to evade detection. Read more about Lazarus APT operations and APT Lazarus using Python scripts

2. Dark Pink

Known for: Targeting military, government, and religious organizations in APAC and Europe.

Group-IB has documented Dark Pink’s campaigns in two major research articles. They highlight techniques such as custom malware and spear phishing. Check Dark Pink: Episode 2 and APT Dark Pink first exposure

3. SideWinder

Known for: Aggressive phishing and document exploit campaigns targeting military and government entities.

Group-IB researchers mapped out SideWinder’s infrastructure and tactics, including spear phishing via fake government portals. Full investigation on SideWinder

4. Tonto Team

Known for: Espionage campaigns against the diplomatic and military sectors.

Group-IB’s report details their toolsets and social engineering techniques, emphasizing sustained targeting of high-value individuals. Read the Tonto Team blog

5. APT41 (aka Double Dragon)

Known for: Mix of espionage and financially motivated cybercrime

APT41 is notable for conducting both intelligence operations and cyber heists. Their campaigns have targeted software vendors, healthcare, and gaming platforms using advanced tools like “ShadowPad” and “KEYPLUG.” Read Group-IB’s deep dive on APT41

How Do I Prevent an APT?

Here’s what you can do:

  • Keep an eye on your network 24/7: APTs thrive on going unnoticed. Tools like Group-IB’s Managed XDR can help you spot suspicious activity before things get serious.
  • Limit who can access what: Only give people the data and tools they need. The fewer doors attackers can open, the better.
  • Train your team regularly: Most APTs start with a simple email. Teaching employees how to spot phishing or sketchy links goes a long way.
  • Fix weak spots before attackers find them: Run regular security checks. Group-IB’s Security Assessment helps identify gaps in your defenses so you can patch them up in time.
  • Use threat intelligence to stay ahead:  Knowing how attackers think helps you stop them. Group-IB Threat Intelligence gives you real-time insights into threats targeting your industry.
  • Update software and systems often:  It’s basic, but critical. Outdated software is a favorite entry point for attackers.
  • Watch your digital footprint: With Group-IB’s Digital Risk Protection, you can monitor your digital footprint for exposed credentials, fake websites, or stolen data before it’s used against you.
  • Have a plan for when things go wrong: Don’t wait until you’re under attack. Build and test an incident response plan. Group-IB’s experts can help guide and support you if and when something happens.

Get Our APT Readiness Checklist

Is your organization prepared to detect and respond to an Advanced Persistent Threat? Use this checklist to assess your current posture and identify gaps in your APT defense strategy.

1. Network Visibility and Monitoring
  • Do you monitor east-west (internal) and north-south (inbound/outbound) traffic?
 Yes/No
  • Are you using tools like NDR or Managed XDR for real-time threat detection?
 Yes/No
  • Are anomaly detection systems in place to spot unusual behavior?
 Yes/No
  • Do you have alerts for data exfiltration, privilege escalation, or lateral movement?
 Yes/No

2. Identity & Access Controls
  • Is multi-factor authentication (MFA) enforced for all users, especially admins?
  • Do you follow the principle of least privilege (PoLP)?
 Yes/No
  • Are user accounts regularly reviewed and access rights updated?
 Yes/No
  • Are dormant or unused accounts disabled promptly?
 Yes/No

3. Threat Intelligence
  • Do you use threat intelligence feeds to stay updated on known APT groups?
 Yes/No
  • Can you correlate Indicators of Compromise (IOCs) with your environment?
 Yes/No
  • Do you receive context-rich insights on attacker TTPs (Tactics, Techniques, Procedures)?
 Yes/No
  • Is threat intel integrated into your detection and response systems?
 Yes/No

4. Endpoint and Infrastructure Hardening
  • Are all systems and applications regularly patched and updated?
 Yes/No
  • Do you have EDR tools deployed and configured correctly?
 Yes/No
  • Are critical assets segmented and protected by layered defenses?
 Yes/No
  • Do you regularly assess the security of third-party and supply chain partners?
 Yes/No

5. User Awareness and Training
  • Do employees receive training on phishing and social engineering tactics?
 Yes/No
  • Are there phishing simulations or tabletop exercises conducted regularly?
 Yes/No
  • Is there a clear channel for employees to report suspicious behavior?
 Yes/No

6. Incident Response and Recovery
  • Do you have a documented incident response plan (IRP)?
 Yes/No
  • Have you tested your IRP with real-world APT scenarios?
 Yes/No
  • Can you isolate compromised systems quickly to limit attacker movement?
 Yes/No
  • Are backups secured, segmented, and tested for recovery integrity?
 Yes/No

7. Posture Review and External Testing
  • Have you conducted a recent penetration test or red team exercise?
 Yes/No
  • Is your organization regularly audited for security compliance?
 Yes/No
  • Do you work with external experts (like Group-IB) for proactive assessments?
 Yes/No

Readiness Score

Count how many boxes you checked:

  • 21–25: You’re in strong shape, but APTs evolve, keep testing and updating.
  • 15–20: You’ve got solid foundations, but a few key gaps remain.
  • <15: You’re at high risk. Time to prioritize and act quickly.

How Group-IB Helps You Stay APT-Ready

Checking the boxes is a great start, but real readiness requires the right tools. You need to know how today’s APT groups think, move, and adapt, and be ready to counter them at every stage.

That’s where Group-IB comes in.

We combine world-class Threat Intelligence with our Managed XDR platform to help you detect threats, understand them, who’s behind them, what they want, and how to stop them early.

With Group-IB, you can:

  • Spot stealthy APT behavior early, using behavioral analytics and real-time network monitoring
  • Track adversaries by name, with deep intelligence on groups like Lazarus, MuddyWater, and APT41.
  • Respond fast and precisely, backed by automated correlation and expert-led investigations.
  • Close visibility gaps across endpoints, cloud, and external attack surfaces

APT groups don’t wait, and neither should you. Contact Group-IB, and let’s assess your real-world readiness together.