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Amplified DDoS
Amplified DDoS attacks are a type of Distributed Denial of Service (DDoS) attack that leverages vulnerable network protocols to magnify the volume of attack traffic, overwhelming targeted servers or networks. These attacks exploit the amplification factor, where a small request can generate a significantly larger response from vulnerable servers. In this comprehensive text, we will explore the details of amplified DDoS attacks, focusing on DNS amplification, NTP (Network Time Protocol), Chargen (Character Generation Protocol), SSDP (Simple Service Discovery Protocol), and other commonly exploited protocols.
Amplified DDoS attacks rely on the misuse of specific network protocols to amplify attack traffic, causing a significant impact on the target. Attackers send a small number of requests to vulnerable servers, forging the source IP address to appear as the target's IP address. The servers, unaware of the falsified source address, respond with much larger responses, flooding the target with amplified traffic.
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DNS Amplification: DNS amplification attacks exploit misconfigured DNS servers that respond to DNS queries with much larger response packets than the initial query. Attackers send DNS queries with the target's IP address as the source, resulting in amplified responses directed at the target. This technique allows attackers to generate massive traffic with minimal resources.
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NTP Amplification: NTP amplification attacks exploit vulnerable NTP servers that respond to NTP queries with large amounts of data. By spoofing the source IP address, attackers send small NTP queries to the servers, which reply with amplified responses, flooding the target with excessive traffic.
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Chargen Amplification: Chargen amplification attacks abuse the Chargen protocol, which generates a continuous stream of characters in response to a request. Attackers send small requests to Chargen servers, which respond with significantly larger data streams. This amplification factor results in high volumes of traffic being directed towards the target.
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SSDP Amplification: SSDP amplification attacks target devices supporting the SSDP protocol, typically used for service discovery in network devices. Attackers send SSDP requests to vulnerable devices, tricking them into sending large responses to the target's IP address. This amplification technique enables attackers to generate substantial traffic volumes.
Amplified DDoS attacks pose significant consequences for targeted systems and networks, including:
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Network Congestion: The amplification factor of these attacks can lead to severe network congestion, overwhelming network links and causing disruption to legitimate traffic flow. This congestion can result in service degradation and connectivity issues for legitimate users.
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Bandwidth Exhaustion: Amplified DDoS attacks consume a vast amount of network bandwidth, saturating network resources and rendering them unavailable for legitimate use. This exhaustion impacts the overall performance of the targeted network and can lead to complete service unavailability.
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Service Disruptions: The flood of amplified traffic can overwhelm targeted servers, causing service disruptions and rendering them inaccessible to legitimate users. This disrupts critical services, resulting in financial losses, customer dissatisfaction, and reputational damage.
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Collateral Damage: In some cases, amplified DDoS attacks may inadvertently affect other organizations or networks that share the same infrastructure or service providers. The impact of collateral damage can have far-reaching consequences, affecting multiple entities within the same network ecosystem.
We have implemented a blocking mechanism for certain source ports associated with rarely used protocols that are vulnerable to amplification attacks. Additionally, we apply rate-limiting specifically to DNS and NTP protocols, as they are commonly utilized UDP protocols. In addition, we enforce rate-limiting on outgoing ICMP messages and UDP traffic to effectively reduce both CPU load and outgoing traffic volume.