'Loop DoS' Attack

A "Loop DoS" attack, also known as a "Loop Denial of Service" attack, is a type of cyberattack that targets a computer system or network by exploiting vulnerabilities in software or protocols to create an endless loop of resource-consuming tasks. The goal of a Loop DoS attack is to consume all available system resources, such as CPU cycles, memory, or network bandwidth, thereby rendering the system or network unable to respond to legitimate requests from users or other systems.

In a Loop DoS attack, the attacker typically sends specially crafted requests or data packets to the target system or network. These requests or packets exploit flaws in the target's processing logic, causing the system to enter into an infinite loop or to execute a series of resource-intensive operations repeatedly. As a result, the system becomes overwhelmed and may eventually become unresponsive to legitimate users.

UDP (User Datagram Protocol) is indeed a connectionless protocol that does not include built-in mechanisms for validating the source IP addresses of incoming packets. This characteristic of UDP makes it vulnerable to IP spoofing attacks, where attackers can forge or manipulate the source IP address of UDP packets to appear as though they originated from a different source.

The latest study found that certain implementations of the UDP protocol, including DNS (Domain Name System), NTP (Network Time Protocol), TFTP (Trivial File Transfer Protocol), as well as services like Active Users, Daytime, Echo, Chargen (Character Generator), QOTD (Quote of the Day), and Time, have been identified as vulnerable and can be weaponized to create a self-perpetuating attack loop.

In this attack, two network services are manipulated in such a way that they continuously send responses to each other, resulting in a cycle of amplified traffic that can overwhelm systems or networks, leading to a denial-of-service (DoS) condition. As many as 300,000 servers or devices on the public internet are thought to be vulnerable right now to the recently disclosed Loop Denial-of-Service technique that works against some UDP-based application-level services.

Loop DoS attacks can take various forms and may target different layers of the network stack, including the application layer, transport layer, or network layer. These attacks underscore the importance of proactive security measures and continues monitoring to protect against evolving cyber threats.

Dr. Deepak Kumar Sahu, President & CEO, VARINDIA