Ping requests are small packets of data used by devices to test connectivity, but when sent in
large numbers, they can flood the network with traffic and slow or even shut down the network.
This is called a ping flood attack (or ICMP flood). Learn everything you need to know about a
ping flood – what it is, and can you avoid it.
A ping flood attack, also known as an Internet Control Message Protocol (ICMP) flood or ICMP
flood attack, is a type of distributed denial-of-service (DDoS) attack that uses the ICMP to
flood targeted machines with traffic.
Is there a difference between a ping flood and a DDoS attack? Yes. Ping flooding is usually
categorized as a subset of DDoS attacks, while DDoS attacks aren’t always ping floods:
DDoS attack
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bombards a device with network traffic and makes it inaccessible to others. The attacked
device simply doesn’t have enough resources to handle all the traffic, so it slows or shuts
them down – which is what attackers want.
Message Protocol, to bombard a device with ICMP requests. When sent in large numbers, ICMP
requests can overload the machine.
Ping flood attacks use the Internet Control Message Protocol (ICMP). ICMP is used to determine
whether communication between devices is running smoothly and to diagnose potential network
errors.
Some of the most commonly used ICMP functions are ping and traceroute. They help users with
network diagnostics:
test network speeds and display the routes data packets take from location A to location B.
used, the device sends an ICMP echo request. If it reaches the target server, it will respond
by sending back an ICMP echo reply. The time between sending the request and receiving the
response will also be measured.
Ping requests don’t show traffic routes, but they are useful when checking whether a device
connects to a specific server and how long data packets take to reach it.
You can test it yourself. Open a terminal, type “ping [target IP address],” and press Enter. For
example, “ping 8.8.8.8” will send a ping request to Google’s DNS server and inform you about the
connection speed and quality.
We’ve established that ping requests are used to test connection speeds and diagnose problems,
and they work thanks to the ICMP protocol. However, they can also be abused, which is where the
ICMP flood attacks come into the picture.
Every time an ICMP echo request is sent, the target network device has to use a small amount of
its resources and bandwidth to process it and send back an ICMP echo reply. It’s easy to imagine
that if the target computer received many such requests, they could overwhelm it completely. And
that’s precisely how ICMP flooding works.
Hackers perpetrating such attacks use networks consisting of many devices. Sometimes, they own
these devices, but more often, they infect random devices with malware, making them part of
their botnet. In this way,
attackers can multiply the number of sent ICMP echo request packets by hundreds.
Although all ping flood attacks, by definition, use the ICMP, several types of attacks can be
distinguished based on the methods used by the hackers. Here are the most important ones.
A smurf attack is an ICMP
flood attack that uses the victim’s spoofed IP address to send ping request packets to the IP
broadcast address of a router or{‘ ‘} firewall, a part of a large
network.
The targeted router then sends requests to multiple devices that are a part of the network.
Because the attacker used a spoofed IP address, these hosts send their ICMP echo reply messages
to the victim, flooding it with attack traffic.
The IPv4 protocol has a limitation of a maximum packet size of 65,535 bytes. So, a hacker cannot
send larger ICMP echo requests. They can, however, send large data packets in fragments. The
target device then reassembles these packets, and since most of the networks cannot handle large
data packets, they get overloaded and crash.
So, what is the ping of death command? It’s an obsolete ping flood attack that involved hackers
writing simple ping flood command loops designed to send ICMP echo requests again and again.
These requests were within the size limit but exceeded it once reassembled, causing the target
device to malfunction.
SYN floods aren’t ping flood attacks because they don’t use ICMP, but they’re worth knowing
about.
A SYN flood attack uses a process known as a TCP handshake to establish a connection between two
devices. Under normal circumstances, the device sends a SYN packet and waits for a SYN/ACK
response, which tells it that the request has been acknowledged. Then, it sends an ACK packet,
and the connection is established.
In a SYN flood attack, the attacker sends numerous SYN packets, usually via a botnet, causing
the victim to respond to each one and leave the port open, waiting for an ACK packet that never
arrives. SYN packets continue to flood the victim, and since it uses its resources to
acknowledge and respond to them, legitimate traffic gets blocked out, and the server cannot
function normally.
A ping flood DDoS attack can cause a lot of damage by making the targeted device unresponsive to
regular traffic. It can have many consequences, from loss of reputation to financial losses.
That’s why defense against all kinds of DDoS attacks is crucial.
Here are some strategies used by cybersecurity experts to protect networks from flooding:
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with traffic from single sources by setting a maximum threshold of ICMP requests processed in
a certain amount of time. Requests that exceed the limit are deprioritized or blocked.
functions, which prevents illegitimate ping requests from flooding servers. However, it also
stops administrators from using the ping utility to diagnose server issues.
DDoS attacks. They can, for example, filter out bogus traffic.
Any defense against DDoS attacks and floods is most effective when deployed quickly. That’s why
network monitoring is crucial and allows for a rapid response against threats.
Network traffic monitoring involves gathering and analyzing traffic data to identify anomalies,
such as abnormal traffic spikes or unusual data sources and destinations. Proper traffic
analysis helps determine the type of threat, its severity, and the best possible response.
To monitor and protect the network, administrators can use tools and techniques such as:
hardware- or software-based and help filter malicious traffic, including ping floods or
unwanted SYN packets.
network traffic. They can help identify the sources, types, and volumes of attacks.
learning can help combat various cyber threats, including DDoS and other flooding attacks.
Machine learning algorithms analyze traffic data and learn patterns to detect threats.
While a VPN service cannot replace firewalls or the other mentioned tools, it can be helpful
against some attacks, including floods. For example, in a smurf attack, the attacker uses a
spoofed IP address to flood your device with bogus traffic. But if you use a{‘ ‘}
VPN, it masks your IP, and the attacker is less likely
to discover and abuse it.
The post Ping flood attack: How it works and how you can defend against it first appeared on NordVPN.