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.
За прошедшее время DoS-атаки эволюционировали до распределенных DoS-атак, которые являются более сложными и трудно идентифицируемыми.
Атаки типа "отказ в обслуживании" в двух словах
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 flood атака
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.
Как это работает
- При этой атаке злоумышленник посылает множество ping-пакетов как можно быстрее, не дожидаясь ответа системы-жертвы (flooding).
- 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.
- Чем меньше пропускная способность, тем больше шансов на успех, так как система будет значительно медленнее реагировать на переполненные пакеты.
Ping of Death (PoD)
Если flooding не срабатывает, злоумышленник может прибегнуть к атаке PoD. При PoD злоумышленник посылает команду ping увеличенного размера с вредоносными пакетами.
Как это работает
- 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).
- Переполнение буфера может привести к аварийному завершению работы системы, и именно в этот момент злоумышленники внедряют в систему вредоносное ПО.
Как предотвратить атаки типа "Ping Floods" и "Ping of Death
- Настройка межсетевого экрана
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.
- Установите антивирусное/антивирусное ПО
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.
- Обновление системы
Обновления системы содержат исправления различных уязвимостей и угроз, связанных с DoS-атаками. Использование новейшей системы гарантирует, что вы не станете жертвой DoS-атак.
- Использование 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.
