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.
Au fil du temps, les attaques DoS ont évolué vers des attaques DoS distribuées qui sont plus complexes et plus sophistiquées à identifier.
Les attaques par déni de service en quelques mots
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).
Attaque par inondation Ping
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.
Comment cela fonctionne-t-il ?
- Dans cette attaque, l'acteur malveillant envoie de nombreux paquets ping aussi rapidement que possible sans attendre la réponse du système victime (inondation).
- 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.
- Plus la bande passante est lente, plus les chances de succès sont grandes, car le système ralentira considérablement en essayant de répondre aux paquets inondés.
Ping de la mort (PoD)
Si l'inondation ne fonctionne pas, un attaquant peut choisir d'utiliser l'attaque PoD. Dans ce cas, l'acteur malveillant envoie une commande ping surdimensionnée avec des paquets malveillants.
Comment cela fonctionne-t-il ?
- 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).
- Si une mémoire tampon déborde, le système peut se bloquer, et c'est à ce moment-là que les acteurs malveillants injectent des logiciels malveillants dans un système.
Comment prévenir les attaques de type "Ping Floods" et "Ping of Death" ?
- Configurer un pare-feu
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.
- Installer un antivirus/antimalware
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.
- Mise à jour de votre système
Les mises à jour du système fournissent des correctifs et des corrections pour diverses vulnérabilités et menaces associées aux attaques par déni de service. En utilisant le système le plus récent, vous vous assurez de ne pas être victime d'attaques DoS.
- Utiliser un 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.
