Content Driven Networks (CDNs) have transformed internet traffic management since their inception in the late 1990s. Originally designed to improve user experience and content delivery, CDNs are used in industries such as media, entertainment, education, and e-commerce.

The global content delivery network market size was estimated at USD 23.25 billion in 2023 and projected to hit USD 105.55 billion by 2032. The use of CDN services is increasing, and most web content, including traffic from sites such as Facebook, and Amazon, is now served via CDNs.

However, the prominence of CDNs may have contributed to the rise to CDN-driven attacks like DDoS (Distributed Denial of Service) which could lead to an increase in online service disruptions.

To curb this menace, relying on outdated IT solutions and human intervention are not sufficient and will continue to be detrimental

In this article, we dissect CDN-driven attacks and how to insulate your business or organization from them.

What is CDN?

A content delivery network is a group of servers that are distributed across multiple locations to provide swift delivery of internet content.

When your business website uses a CDN, the CDN's edge servers initially request data from the origin server and cache your website's content before serving it to users.

This implies that instead of users connecting directly to your origin server, they connect to the closest CDN edge server, which returns the cached content.

The communication between the CDN and the origin server is the "back-end" (CDN-to-Origin) connection, while the communication between the CDN and users is the "front-end" (user-to-CDN) connection. Most CDNs could also provide some security features like Denial of Service (DoS) protection for users.

Understanding CDN-Driven Attacks

CDN-driven attacks are cyber attacks that exploit vulnerabilities in CDNs for malicious intent. These attacks often result in DDoS attacks and unauthorized access to sensitive information. 

Most of these kind of attacks may involve initially compromising CDNs and then using the CDN infrastructure for further malicious activities. Moreover, the nature of CDNs make it difficult to detect attacks because malicious activities can occur across multiple network nodes in different geographical locations.

Types of CDN driven attacks

The following are some of the cyber attacks which can be driven through a CDN;

1. Traffic Redirection: Attackers could manipulate DNS records or BGP routing to redirect CDN traffic to malicious servers, enabling interception or tampering with data.

1. DDoS Amplification: By exploiting CDNs, attackers could launch Distributed Denial of Service (DDoS) attacks, flooding target servers with overwhelming traffic volumes. 

1. Cache Poisoning: This is when the attacker injects the CDN cache with falsified content or malware. This causes relevant and important content to be unavailable to unsuspecting users (known as cache misses).

1. Malware delivery: This occurs when a CDN cache poisoned with malware distributes malicious software to CDN end-users, compromising their systems or devices. This manipulation of the CDN cache allows attackers to target unsuspecting users who request content from the CDN, leading to potential security breaches and harm to the end-users' devices or data.

1. TLS certificate breach: These digital certificates authenticate a website's identity and maintain an encrypted connection. They are part of SSL (Secure Sockets Layer), establishing an encrypted link between a CDN web server and a browser. This link ensures that data exchange between the web server and browsers are private. A breach in these certificates will cause impersonation attacksand grant attackers access to the encrypted data.

Impact on target websites and services

• Disruption of Service: CDN-driven attacks like the 2016 incident by Anonymous Legion on the Minnesota Courts website can cause you prolonged downtime, disrupting services.

• Compromised Data Integrity: Attacks like the Magecart incident on Forbes, involving web-skimming scripts, can disseminate compromised content, undermining trust and exposing sensitive information.

• Reputational Damage: CDN-driven attacks can harm your reputation, diminishing trust among users and stakeholders.

Mitigation Strategies 

• Regular security assessments: Conducting regular security audits and assessments of your CDN services to identify vulnerabilities and address them before they can be exploited by attackers.

• Utilize a multi-CDN strategy: Relying on a single CDN provider increases the risk of a single point of failure. A multi-CDN strategy, which involves the distribution of traffic across multiple CDN providers, will enhance service availability and resilience.

• Incident response planning: Developing and regularly testing incident response plans will ensure you have a coordinated and effective response in the event of a CDN attack.

As CDN-driven attacks continue to increase, attackers will resort to more sophisticated techniques to evade detection. Anticipating trends and adopting emerging technologies such as AI and Machine Learning and blockchain technology for defense is crucial.

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