The internet has lots of threats in its Pandora box ranging from malware and identity theft to blackmail and other breaches. One of the most common threats in most networks is the Denial of Service (DoS) attacks. As the name suggests, DoS attacks do the same thing, make resources inaccessible to legitimate users. While at it, malicious actors can propagate further attacks by injecting malware into various systems. Like other many cyber-attacks, DoS attacks usually focus on big giant companies. But with the ‘bring your own device’ rule in most companies, you won’t know when you will fall into their snare. In this case, you will also be the victim.
过去，DoS 攻击已演变为分布式 DoS 攻击，其识别起来更加复杂和精密。
拒绝服务攻击简述
Besides making resources unavailable to users, DoS attacks usually result in system crashes and slowdowns. If crashing doesn’t happen, DoS attacks flood the services (making them slow down). Crash attacks occur when malicious criminals use bugs to exploit vulnerabilities in a system. Eventually, the system will be overwhelmed, and it will crash. This type of DoS attacks is less common.
The major common type of DoS attacks are the flooding attacks. Flooding attacks occur when malicious actors overwhelm a particular system with large amounts of traffic that the system isn’t able to handle. The system eventually slows down or crashes. Flooding DoS attacks include Ping flood and Ping of Death. These attacks take advantage of the Internet Control Message Protocol (ICMP).
Ping 泛洪攻击
This type of DoS attack occurs when a malicious actor overwhelms the target system with packets of information. At times, they can be malicious and take advantage of vulnerabilities in misconfigured devices.
工作原理
- 在这种攻击中，恶意行为者会以最快的速度发送大量 ping 数据包，而不等待受害者系统回复（洪水）。
- For this attack to be executed successfully, the malicious actor should have more bandwidth than the victim. When the victim’s system starts to respond to the packets, it will take as much as twice the bandwidth the attacker used to send the packets.
- 带宽越慢，成功的几率就越大，因为系统在尝试响应泛洪数据包时会明显减速。
死亡之屏（PoD）
如果泛洪不起作用，攻击者可能会选择使用 PoD 攻击。在 PoD 攻击中，恶意行为者会发送带有恶意数据包的超大 ping 命令。
工作原理
- Most systems rely on the Internet protocol to communicate over the internet. This protocol usually doesn’t allow packets larger than 65,535 bytes. In these attacks, a malicious actor sends packets larger than the maximum size, and the systems can’t deal with them. As a result, they crash and services are disrupted.
- Malicious actors usually send the larger malformed packets in fragments in their transmission. The receiving system will then start to assemble them, but they will become too larger and cause a buffer overflow. (Buffers store some data for a short period).
- 如果缓冲区溢出，系统就会崩溃，而恶意程序就是在这个时候向系统注入恶意软件的。
如何防止 Ping Flood 和 Ping of Death 攻击
- 配置防火墙
For general users, a firewall is the first option to consider. A firewall prevents unauthorized access to your system. When appropriately configured, a firewall can block malicious actors from perpetrating DoS attacks.
- 安装杀毒软件/反病毒软件
Reputable up-to-date antimalware and antivirus software can protect you against malicious codes injected by cybercriminals when DoS attacks occur. As a bonus, reputable antimalware/antivirus software has a firewall.
- 更新您的系统
系统更新提供了与 DoS 攻击相关的各种漏洞和威胁的补丁和修复程序。使用最新系统可确保您不会成为 DoS 攻击的受害者。
- 使用 VPN - IPBurger
To perform DoS attacks, a malicious actor needs to know the victim’s IP address. Since a VPN masks your real IP address and replaces it with a virtual IP address, you will be safe from these attacks.
