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C&C server

(also command and control server, command and control infrastructure, C2)

C&C server definition

A C&C server is a centralized server or a network of servers used by attackers to manage and control compromised devices or systems within a botnet or malware network. The purpose of a C&C server is to enable communication between the attacker and the compromised devices. This allows the attacker to send commands, receive information, and coordinate malicious activities.

See also: botnet, firewall

C&C server use cases

  • Botnet Control: C&C servers are often used to control and manage botnets (networks of compromised devices) infected with malware. The C&C server acts as a command center, allowing the attacker to send instructions and control the activities of the botnet, such as launching DDoS attacks, sending spam emails, or distributing malware.
  • Malware Distribution: The C&C server acts as a repository or distribution point for malware, allowing the attacker to push updates, deliver new versions of malware, or distribute malicious payloads to compromised devices.
  • Data Theft and Exfiltration: C&C servers enable cybercriminals to extract sensitive information from compromised devices. The server can receive stolen data, so that the attacker can exploit or sell it.
  • Command Execution: C&C servers let attackers to remotely execute commands on compromised devices. This includes running specific scripts, initiating malicious activities, installing additional malware, or modifying configurations on the compromised systems.
  • Updates and Configuration Changes: C&C servers can distribute updates or configuration changes to the compromised devices. This way the attacker can enhance or modify their malware, evade detection by security tools, and adapt to changing conditions.
  • Information Gathering: C&C servers can collect information from compromised devices, such as system information, network configurations, or logs. This information helps the attacker assess the compromised network's capabilities, identify potential targets, or gather intelligence for future attacks.

Protection from malicious attacks involving C&C server

  • Use reliable security solutions. Get trustworthy cybersecurity tools like antimalware software.
  • Keep your systems up to date. Regularly update your operating system, software, and applications with the latest security patches.
  • Use a firewall. Activate a firewall on your network and individual devices to control incoming and outgoing traffic and configure it to block suspicious connections, especially those associated with known C&C server IP addresses.
  • Monitor network traffic: Use network monitoring tools to identify suspicious traffic. Look for any unusual connections, unusual ports, and large amounts of data being transferred to unknown destinations.
  • Practice safe browsing habits. Avoid clicking on suspicious links or opening email attachments from unknown sources.
  • Use strong and unique passwords. Ensure that you have long and complex passwords for your accounts and implement two-factor authentication (2FA) whenever possible.
  • Regularly backup your data: Maintain up-to-date backups of your important files and data. Store the backups in a secure location that is separate from your primary network.
  • Implement network segmentation. Separate your network into different segments, particularly isolating critical systems from general network traffic.
  • Educate yourself and your employees. Stay informed about the latest cybersecurity threats and provide cybersecurity training to your employees.
  • Regularly review logs and conduct incident response drills. Establish an incident response plan and conduct drills to ensure you can respond effectively in case of a breach.