Common types of cyberattacks, reasons for website inaccessibility, and solutions-阿里云帮助中心

This topic describes common types of cyberattacks, explains why they can make a website inaccessible, and provides solutions.

Problem description

A website can be targeted by various cyberattacks that disrupt normal operations. Two common types of attacks are zombie attacks and DDoS attacks.

Zombie attack: A hacker intrudes on a computer and plants back door programs, such as viruses or trojans. The hacker then obtains administrative permissions and can remotely control the computer.
DDoS attack: A distributed denial-of-service (DDoS) attack aims to prevent legitimate users from accessing network resources.
Note
Common DDoS attack methods include SYN Flood, ACK Flood, UDP Flood, ICMP Flood, TCP Flood, Connections Flood, Script Flood, and Proxy Flood.

Different types of cyberattacks, such as zombie attacks or DDoS attacks, can make your website inaccessible.

Troubleshooting	Solution
Program-level checks	Regularly check your website for suspicious executable files, such as .exe, .bat, .cmd, .vbs, .sh, .jsp, .php, .asp, .py, and .cmd. Avoid using component-free uploaders and third-party controls. If you use third-party controls, update them to a secure version. Regularly back up your database and website programs.

Troubleshooting	Solution
Program checks	Check your website program for vulnerabilities. Remove any content that could be attacked to prevent similar attacks from recurring.
Competitor checks	Check for malicious attacks from competitors and handle them promptly.
Program and security prevention	Program prevention: Encrypt your code using methods such as Zend or MD5. This helps prevent hackers from exploiting program vulnerabilities to plant trojans or viruses, which could then be used to launch a DDoS attack. Security protection: Strengthen the security measures for your host. Use complex passwords for all host credentials, such as the logon password, FTP password, and database password. Simple passwords are easy for hackers to crack. A compromised host can be used as a zombie to launch DDoS attacks against other servers.