Site Crashed? Not Your Bank's!

Develop bank applications that resist DDoS attacks

Blog Site Crashed? Not Your Bank's!

| 5 min read

Contact us

What's this trend of DDoS attacks against banks?

Distributed denial-of-service (DDoS) attacks are hitting the banking industry hard. This kind of attack involves the delivery of a high amount of requests or data from different sources (e.g., systems) to a site, server or network resulting in degradation of availability of the service that depends on that site, server or network. According to a report released in March 2024, DDoS attacks against financial services rose by 154% between 2022 and 2023. The report further identified banks as the most impacted firms within the financial services sector worldwide during 2023, accounting for 63% of all DDoS attacks.

There are several factors that may be behind the surge in DDoS attacks. For example, recent spikes in hacktivism amid geopolitical tension, which incites cyberattacks overall, has meant more DDoS attempts, on which firms are, by the way, keeping a more watchful eye lately. Indeed, as hacktivists (e.g., pro-Russian groups) have announced their intent to hit financial organizations in the US and Europe, these orgs have reported more attempts than in the past, it seems, in part, due to their heightened vigilance. Other factors are the rise of DDoS-for-hire services (i.e., the possibility to rent the system network used to overwhelm the target site, server or network), which make conducting the attacks a less costly affair, and the all-too-common search for financial gain. An enabling factor for attack success is the lack of adequate DDoS protection. We'll get to advice on this later.

One example of a DDoS attack in the sector is that which some of Denmark's largest banks experienced in early 2023. The pro-Russian hacktivist group NoName057(16) conducted the attack, affecting the websites of nine target institutions. Reports say the websites were down for a short period of time, but still, the disruption caused operational delays in the organizations.

The rising threat of DDoS attacks should place your bank on high alert. Service disruptions mean delays and customer dissatisfaction and distrust. Moreover, DDoS attacks, as argued in the above report, may be part of a ransomware attack where threat actors try to coerce orgs to pay the ransom by promising service disruption otherwise. Stakes are high, so you need to get ready for this type of attack. Let’s first go into what it is.

What is a DDoS attack?

A distributed denial-of-service attack is an attempt to overwhelm websites, servers or networks with a flood of specific traffic, like messages, connection requests or malformed packets.

An attacker can gain control of one device by exploiting an unpatched vulnerability, or through malware infection after successful phishing attacks or even by brute force. Afterwards, the attacker builds kind of an army ("zombie army," some call it) of compromised devices or bots through an established communication channel of infected devices. This is called a botnet. To manage the botnet remotely, the attacker uses a command-and-control, or C&C, server. Once the latter is ready, the attacker issues commands to the botnet to attack the target system, creating a disruption that can affect the target's bandwidth, processing power or memory. The havoc produced in the operation of the target prevents legitimate users from accessing it, either at the desired speed or altogether.

The duration of service unavailability due to DDoS attacks varies quite a lot. Indeed, historically, it ranges from a few minutes to days. The longest DDoS ever lasted an uncommonly 21 days. This was in 2019. Recent data by Cloudflare shows that in early 2024 almost half of DDoS attacks lasted over 10 minutes, while about one-third lasted more than one hour. These two pieces of info are in relation to application-layer attacks. This specific category refers to when the botnet floods applications with a high volume of seemingly legitimate requests, as if it were end users utilizing the applications' functionalities.

As DDoS attacks at the application level have increased, it's important for IT leaders in banks to address the security of the bank applications in relation to this type of attack. Below, we give our recommended security requirements for software which should make part of your DDoS mitigation strategies.

Get started with Fluid Attacks' Security Testing solution right now

Prevent DDoS right from application development

The cybersecurity industry offers DDoS mitigation solutions. These are tools and services for preventing, detecting and stopping DDoS attacks. They are meant to make your application more resistant without you needing to have protection built into the application itself. An example is web application firewalls (WAFs), which you deploy to inspect and block incoming traffic based on predefined rulesets, such as high request rates or anomalous patterns.

Yet, you should want your banking application to be strong itself when DDoS mitigation solutions falter. That is key for your DDoS prevention plan. Our next recommendations are then directed at developing applications secure against DDoS attacks by design.

  • Implement rate limiting: Set up rate-limiting mechanisms to restrict the number of requests from a single source or IP address over a specified period.

  • Use request validation: Validate incoming requests to ensure they conform to expected patterns, such as size, frequency, and content types.

  • Build allowlists and blocklists: Set the IPs for which the rate limit does not apply and those that must be blocked (e.g., malicious IPs that have already been reported as such).

  • Introduce CAPTCHA or challenge-response mechanisms: Require human verification for pages for which suspicious or potentially malicious requests can be expected. This can help differentiate between legitimate users and bots.

  • Enable horizontal scaling: Design applications to be horizontally scalable, that is, able to distribute the workload across multiple machines or servers, thus managing user requests and transactions more effectively, reducing the risk of downtime and avoiding performance bottlenecks. This scalability is crucial to support a growing user base, high transaction volumes and fast services.

  • Use load balancing: Deploy applications behind load balancers that can distribute incoming traffic evenly across multiple servers. This helps absorb and distribute the impact of DDoS attacks.

  • Have distributed architecture and redundancy: Design applications with distributed architectures and redundant components that can withstand localized failures and mitigate the impact of DDoS attacks by maintaining service availability from alternative locations or servers.

At Fluid Attacks, we help you find and remediate the security vulnerabilities in your banking applications. Start the 21-day free trial of Continuous Hacking to enjoy automated security testing that can detect noncompliance with DDoS-related security requirements, such as setting a rate limit. You can enjoy using our platform to manage the detected vulnerabilities and syncing it with VS Code to use the AI-generated fixes options that we offer in the latter. What's more, for enhanced security against DDoS attacks, you can get our Advanced paid plan, which adds vulnerability analysis by our hacking team. This team will not only find vulnerabilities that tools will not detect, but also give expert advice to your development team on how to eliminate them. Sounds better? Contact us to learn more.

Subscribe to our blog

Sign up for Fluid Attacks' weekly newsletter.

Recommended blog posts

You might be interested in the following related posts.

Photo by Wilhelm Gunkel on Unsplash

Transparency for fewer supply chain attacks

Photo by Towfiqu barbhuiya on Unsplash

Ensuring compliance and security in the banking sector

Photo by Andre Taissin on Unsplash

With great convenience comes increased risk

Photo by FlyD on Unsplash

Software supply chain management in financial services

Photo by Robs on Unsplash

Consequential data breaches in the financial sector

Photo by Towfiqu barbhuiya on Unsplash

Data protection in the financial sector, tips and more

Photo by Jasmin Egger on Unsplash

If the essential security layer is flawed, you're toast

Start your 21-day free trial

Discover the benefits of our Continuous Hacking solution, which hundreds of organizations are already enjoying.

Start your 21-day free trial
Fluid Logo Footer

Hacking software for over 20 years

Fluid Attacks tests applications and other systems, covering all software development stages. Our team assists clients in quickly identifying and managing vulnerabilities to reduce the risk of incidents and deploy secure technology.

Copyright © 0 Fluid Attacks. We hack your software. All rights reserved.