Advanced Persistent Threats (APT) are among the most dangerous types of cyberattacks due to their long-term planning and sophisticated techniques, which allow attackers to remain undetected within targeted networks for extended periods. These attacks commonly target government institutions, major corporations, and critical sectors to conduct espionage, steal sensitive information, or disrupt systems and services. APT attacks rely on various techniques, including spear phishing, exploiting security vulnerabilities, stealing login credentials, and deploying malicious software. They typically involve multiple stages, beginning with reconnaissance and initial access, followed by persistence, privilege escalation, and eventually collecting and exfiltrating sensitive data outside the targeted organization. Combating these threats requires advanced security technologies such as Intrusion Detection Systems (IDS), Security Information and Event Management (SIEM), and Endpoint Detection and Response (EDR). These technologies, alongside user behavior analysis, threat intelligence, and artificial intelligence, help identify suspicious activities and detect attacks at an early stage. Furthermore, security measures such as regular system updates, Multi-Factor Authentication (MFA), network segmentation, access control, secure backups, and security awareness training play an essential role in reducing these risks. Early detection and rapid incident response remain key factors in protecting digital infrastructure and strengthening cybersecurity.