DNS and PKI Digital Security: The Hidden Threat

In today’s interconnected financial world, every click, transaction, and transfer you make relies on an intricate web of digital security systems. Behind the scenes, two key pillars ensure the safety of your digital interactions: Domain Name System (DNS) and Public Key Infrastructure (PKI). These systems translate web addresses into numerical IP addresses and secure online communications through cryptographic certificates. Yet, what happens when these invisible gatekeepers are left unmanaged?

For global banks, which process trillions of currency in daily transactions, poor DNS and PKI security can have catastrophic consequences. From lost revenue and shareholder confidence to operational disruptions and compliance breaches, the impact is far-reaching and often underestimated. In this article, I shine a light on three historical incidents that reveal the scale and devastation of these often-overlooked security vulnerabilities and how to protect your organisation from the same fate.

1. SolarWinds DNS Hijacking and Certificate Exploitation (2020): A Supply Chain Nightmare

Few breaches in history have been as far-reaching and devastating as the SolarWinds hack of 2020. The attack infiltrated over 18,000 organisations, including Fortune 500 companies and key Government agencies, by planting malware in SolarWinds' Orion platform. Attackers used DNS hijacking and exploited weaknesses in digital certificates to maintain long-term access to sensitive systems, all through a seemingly legitimate software update.

The consequences? SolarWinds' stock plummeted by 40% almost immediately. Reuters reported that at least 200 targeted organisations suffered significant operational disruptions, leading to millions in revenue losses as they scrambled to assess and contain the damage. For national Governments and companies like Microsoft, the breach represented not just a loss of data, but a critical failure in supply chain security. The ripple effects included a re-evaluation of vendor relationships, stricter compliance with digital security guidelines, and increased scrutiny of digital certificates.

From a strategic perspective, the SolarWinds breach highlights a profound vulnerability in third-party and fourth-party relationships. As more organisations depend on third-party vendors for their IT infrastructure, the risk of DNS hijacking and certificate exploitation becomes increasingly acute.

How many of your suppliers have the same level of security controls as your organisation?

Learning the Lessons:

Business leaders must implement DNS monitoring solutions such as Palo Alto Networks, whose products detect and block malicious DNS activities before they can compromise critical systems. Also, consider enforcing zero-trust architecture security models.

Continually audit the DNS and PKI security postures of your supply chain partners, ensuring that even third-party certificates are trustworthy and validated.

2. DigiNotar PKI Compromise (2011): A Chain of Trust Broken

It was 2011 when Dutch certificate authority (CA) DigiNotar fell victim to an attack that would not only cost them their business but also shake global confidence in the entire Public Key Infrastructure (PKI) system. Hackers managed to issue over 500 fraudulent SSL certificates, enabling them to impersonate websites like Google and Microsoft. The breach was particularly devastating in Iran, where over 300,000 users became vulnerable to Man-in-the-Middle (MitM) attacks, allowing threat actors to intercept secure communications.

The aftermath? DigiNotar went bankrupt within months, facing lawsuits and international condemnation. Ponemon Institute estimates that breaches involving PKI trust services typically result in legal and compensation costs ranging from ￡2.5-￡5 million. Worse, the very companies and individuals who relied on these certificates found themselves exposed to cyber espionage, data theft, and operational chaos. Google reported that - despite an immediate incident response - the fraudulent certificates remained active for at least six weeks, potentially affecting the secure communications of millions of users.

This breach exposed the fragility of the global PKI system: when a trusted authority is compromised, the entire chain of trust can fall apart, with far-reaching consequences for businesses and users alike.

If your trusted certificate authority were breached tomorrow, how many of your critical communications would be at risk?

Learning the Lessons:

Organisations must adopt centralised certificate management solutions like those from Venafi or DigiCert, ensuring that fraudulent certificates can be quickly identified and revoked. Also, employing automated certificate renewal and monitoring systems helps avoid the risks of expired or compromised certificates disrupting critical communications.

3. Turkish ISPs DNS Hijacking (2014): Censorship, Surveillance, and Chaos

Imagine being unable to access Twitter or other vital social platforms during a time of political unrest. In 2014, during widespread protests in Turkey, this became a reality. The Turkish Government, in an attempt to suppress dissent, blocked access to social media by manipulating DNS queries. But they didn’t stop there. Turkish Internet Service Providers (ISPs) hijacked DNS requests, redirecting users to government-controlled servers.

What was the impact?

Over 10 million users were unknowingly redirected, unable to access critical information or communicate. E-commerce and banking platforms suffered, with businesses losing revenue and consumer confidence shaken. According to the International Monetary Fund (IMF), internet restrictions can cost economies up to ￡1.2 billion per day globally. The fallout extended beyond Turkey, as global corporations operating in the region experienced operational disruptions and reputational damage, wondering how their traffic could be so easily hijacked.

But the most disturbing element of this incident is the legal and ethical implications. DNS hijacking by ISPs raised questions about privacy, internet freedom, and state surveillance.

Could your business operations survive if your communications were similarly hijacked by a third party or government entity?

Learning the Lessons:

To prevent such DNS-based attacks, global organisations should consider implementing DNS Security Extensions (DNSSEC), which authenticate DNS queries and responses, ensuring that malicious redirects are identified and blocked before they reach users. Companies like Cisco offer robust protections, ensuring the integrity of DNS traffic even in politically or commercially sensitive environments

Major DNS and PKI Security Exposures

Financial Services organisations and banks, responsible for processing billions in daily transactions, are highly susceptible to DNS and PKI-related attacks due to their complex IT infrastructures, multi-cloud environments, and global vendor networks. Below are three critical security exposures:

1. DNS Spoofing and Cache Poisoning

DNS attacks, such as spoofing and cache poisoning, redirect legitimate traffic—such as payment instructions—to malicious sites. In global banks, this can lead to millions in financial losses and operational disruptions, particularly in payment systems like SWIFT or SEPA.

How To Tackle The Risk?

Consider implementing DNSSEC to authenticate DNS responses and prevent tampering. Companies like Cisco or Cloudflare provide global DNS protection, ensuring secure transactions across global markets

2. Expired and Revoked Certificates

Implications: Inadequate PKI management can cause service outages or expose sensitive customer data. Expired certificates can lead to unencrypted communications, potentially violating GDPR and PCI DSS regulations.

How To Tackle The Risk?

Use automated certificate lifecycle management companies like DigiCert or Venafi to ensure certificates are renewed and revoked as needed, keeping banking services secure and operational

3. Weak Encryption and Deprecated Algorithms

Implications: Using outdated encryption algorithms like SHA-1 exposes banks to breaches and espionage, compromising highly sensitive information (PII, PCI, CSI).

How To Tackle The Risk?

Enforce modern encryption standards like TLS 1.3 and SHA-256. Use tools like those from Qualys to continuously audit encryption protocols

Proactive Defence Strategies

Given these exposures, global banks must adopt a proactive stance to mitigate risks. Incorporating both best-in-class tools and strict security policies can significantly reduce vulnerability to DNS and PKI-related attacks.

• Adopt DNSSEC:

Protect your organisation from DNS hijacking and spoofing by considering implementing DNSSEC across all your DNS queries. Solutions like Cloudflare DNSSEC or Cisco Umbrella offer real-time DNS protection, ensuring that only legitimate traffic is routed through your networks.

• Automate PKI Management:

Use platforms like Venafi or DigiCert CertCentral to automate the lifecycle management of certificates. This ensures that expired or revoked certificates do not expose sensitive data or disrupt services.

• Enforce Strong Encryption:

Modern encryption standards such as TLS 1.3 and SHA-256 are essential. Tools like those from Qualys allow banks to audit encryption protocols and ensure compliance with the latest security standards.

By implementing these defence strategies, organisational leaders can mitigate the risks of DNS and PKI vulnerabilities, safeguarding their operations and ensuring the security of their global financial systems.

Final Thought: The Clock is Ticking...

In an age where global transactions and financial operations rely on digital infrastructure, the integrity of DNS and PKI systems is paramount. Failing to secure these pillars leads to service outages, financial losses, and catastrophic data breaches.

It's a shocking truth that business leaders, large institutions and government entities that store and process highly sensitive CNI, public health, transport, markets, payments, intellectual property, and national defence information - fail to secure their digital DNS and PKI infrastructure. Industry experts such as Andy Jenkinson work tirelessly to shine a light on this topical issue. I highly recommend his expertise in evaluating your digital security posture.

As these real-world examples show, proactive security is no longer optional—it’s a necessity.

If your DNS and PKI systems were attacked tomorrow, would your organisation be able to weather the storm?

Now is the time to act, before a hidden threat becomes an open disaster.