What Is Advanced Persistent Threat?

• Advanced persistent threat (APT) Definition

  Advanced persistent threat (APT) Definition

  Advanced persistent threat (APT), a strategic and stealthy attack, allows attackers to infiltrate an organization's network using a combination of malicious tools, techniques, and procedures such as social engineering, rootkits, and exploit kits. Unlike "hit-and-run" attacks, APT is a "low-and-slow" and planned attack with an underlying motive of stealing valuable information from the target systems or organizations over an extended period without getting detected.
• Types of advanced persistent threats

  Types of advanced persistent threats

  Before we discuss types of advanced persistent threat (APT), let’s revisit the definition. APT attacks originate from a group of people known as threat actors. Their motives include intellectual property theft and corporate espionage. Usually, these actors are well-funded by large organizations and state governments. Some well-known global APT groups include Lazarus Group, Fancy Bear, Machete, and Elfin. The term "threat" in APT also refers to skilled, covert, and sophisticated intruders specializing in executing a well-organized cyberattack against specific targets, typically government networks and large organizations, and using attack vectors such as:

  • Social engineering: One of the oldest and successful tactics APT actors employ to gain initial access to a network by manipulating unsuspecting users or employees. Popular attack techniques of social engineering include:
  • Phishing: Sending well-designed, authentic-looking emails or text messages to create a sense of urgency, fear, or curiosity among targets and thus, prod them to reveal sensitive information. APT groups often send malicious payloads or ransomware alongside phishing emails to infect the target systems.
  • Spear phishing: Selecting particular individuals or businesses in a phishing attack is known as spear phishing. This is more prevalent in APT attacks as the size of the target group is limited, increasing the likelihood of unnoticed exploitation. Carefully crafted messages according to targeted individuals' characteristics and job positions make the attack less dubious. It allows threat actors to easily capture privileged users' credentials through keylogger once they click on suspicious text or emails.
  • Rootkits: A malicious software program that provides attackers remote control over a target system via the command-and-control servers while masking its presence. Once inside the infected systems, rootkits create backdoors for APT groups to access the organization network without getting detected. Rootkits installations rely on common attack vectors used for any malware, such as email phishing campaigns.
  • Exploit Kits: An exploit is a shellcode that automatically scans vulnerabilities across the target system and, if found, installs malware to perform unauthorized activities. Exploit kits, on the other hand, are comprehensive repositories of multiple exploits. APT actors typically deploy exploit kits in the victim's system through malicious websites and emails. Clicking links on compromised websites or emails redirects users to attacker-control landing pages that scan victims' devices for vulnerabilities to launch an attack or install malicious payload.
  • Other methods: There are countless ways to launch an advanced persistent threat (APT) attack, such as DNS tunneling, rogue Wi-Fi, and drive-by-downloads. The selection of APT attack vectors largely depends on the threat actors' intentions and attack strategy.
• How an advanced persistent threat works

  How an advanced persistent threat works

  Threat actors executing advanced persistent threats often apply a systematic approach to access a company's network. Outlined below are the stages of a successful APT attack:

  1. Initial Access: APT groups often initiate attacks by exploiting vulnerabilities across an organization's three attack surfaces: network devices, web assets, and privileged human users. They can apply various social engineering tactics such as spear phishing emails for initial infiltration. Additionally, intruders can spike the network traffic through DDoS attacks to distract security teams.
  2. Establish a foothold: After initial access, attackers deploy a backdoor shell, a remote access trojan (RAT), or other malware in the infected system to gain remote access to the network. Establishing an outbound connection with command-and-control (CnC) servers is also crucial for attackers at this stage to control the compromised systems.
  3. Increase control with lateral movement: Attackers expand their presence by exploiting more vulnerabilities inside the network for more profound control. They also use keyloggers and brute-force attacks to obtain sensitive password information to enhance their privileges. Creating additional backdoors or building a botnet allows attackers to perform lateral movement and devise an ideal attack strategy.
  4. Stage the attack: Detailed internal reconnaissance allows attackers to identify the most valuable data; stealing or damaging it can wreak havoc on any organization. They encrypt, compress, and transfer such information to a secure location for exfiltration at a later stage. It often takes time as attackers are looking to jeopardize more sensitive systems outside their attack zone.
  5. Exfiltrate and execute follow-up attacks: At last, APT attackers extract the sensitive data outside the organization's security perimeters without detection, leaving the network compromised. Tactics like denial-of-service (DoS) are put into action to divert the security team's attention during exfiltration. Attackers may decide to stay inside the network if the exfiltration event is undetected. They wait for opportunities to launch subsequent attacks or create strong backdoors that are hard to detect to regain access to the company network in the future.
• What is the key difference between APT and malware?

  What is the key difference between APT and malware?

  The primary objective of an APT attack is to steal data persistently and evasively for an extended period without causing any severe damage to the target systems. APT actors silently move through the target systems or network to scan vulnerabilities, thereby making the attack even more persistent.

  Malware, in contrast, is a collective term for all kinds of harmful software such as trojans and worms that causes immediate damage to your computer systems. Unlike advanced persistent threats, detecting and eradicating malware isn’t very difficult. The frequency of malware attacks is also very high compared to APTs.
• How to prevent the advanced persistent threat

  How to prevent the advanced persistent threat

  Prevention from an APT is often challenging due to its inherent nature—avoiding detection and staying hidden. However, combatting APT is possible with the strategic and coordinated application of security techniques and tools. Instead of employing disjoint, separate tools for network security, companies can use a unified solution such as security information and event management (SIEM) software to evade APT attacks. Next-gen SIEM solutions offer advanced protection against APTs with early threat detection, investigation, and response.

  Outlined below are other ways how SIEM tools can help you impede APT attacks:

  Real-time data collection and normalization: SIEM solutions can normalize and categorize logs and event data collected from multiple network devices and applications easily. This helps you monitor numerous events, such as software installs and incoming and outgoing traffic, that can allow an APT to enter your network. For example, unusual network spikes may emerge from data exfiltration by APT groups. Having detailed information on such events can accelerate the threat detection process.

  Customized dashboards and visualizations: Traditional network monitoring and security tools often lack innovative data visualization capabilities limiting network teams from quick diagnosis of suspicious network activities. However, unlike traditional tools, SIEM solutions enable network teams to gather the security event logs in real-time and analyze them quickly via dashboard visualizations with customization options. This, in turn, helps organizations stay better prepared against APT attacks. 

  Prebuilt templates for compliance reporting: Pre-configured templates in SIEM solutions enable IT teams to quickly generate the standard audit reports and comply with various security standards, such as PCI DSS and SOX. Regular security audits also make organizations less prone to APT attacks.

  Automated threat detection and response: SIEM solutions provide threat intelligence capabilities enabling organizations to continuously detect and respond to malicious activities of APTs in their network. The continually updated threat intelligence feeds in SIEM tools source potential and existing threat information, including indicators of compromise (IoC), from multiple external sources. Having such data enables organizations to respond faster to known threats in their network by setting automated responses, such as blocking IP addresses and domains tied to unauthorized activities.

  File integrity monitoring (FIM): SIEM tools can detect unauthorized changes in your file system and critical applications owing to zero-day malware and other advanced threats. The built-in FIM tools scan every low-priority change across your file system and offer layered protection that restricts APTs from making illicit modifications in operating system files, device configurations, and user accounts.

  Endpoint protection: APT attacks often leverage endpoint devices such as laptops and mobile phones to infiltrate a network. Besides formulating robust BYOD policies, organizations can leverage SIEM applications to prevent endpoint data loss by receiving real-time alerts of unauthorized USB device connections and subsequently blocking their usage.

  Log forwarding: With SIEM tools, organizations can download the logged events data in multiple formats and share it with concerned security teams and other stakeholders for a strategic, coordinated response against APT attacks. Sharing data with external vendors or security specialists can help organizations formulate a robust cybersecurity framework for improving their overall security posture.