Risks from Legacy and Unpatched Systems in Critical Infrastructure
A new Cisco report highlights the growing risk posed by legacy and unsupported systems within national critical infrastructure, revealing that nearly half of global business network assets were already aging or obsolete as of 2020. The United Kingdom, in particular, faces significant exposure, with 228 legacy systems identified across government in 2024 and over a quarter at high risk of operational or security failure. The report underscores that unsupported systems, often located at network edges, are prime targets for attackers, and that a majority of breaches in the EU during 2022 and 2023 exploited vulnerabilities with available but unapplied patches. Healthcare and other essential sectors are especially vulnerable due to concentrated use of outdated technology.
Recent cyberattacks have increasingly targeted legacy firewalls and network devices, with state-sponsored groups exploiting known vulnerabilities in products from vendors such as Cisco, SonicWall, Palo Alto Networks, and Fortinet. Research indicates that 60% of enterprise firewalls fail high-severity compliance checks, reflecting deeper governance and patch management issues. Attackers are leveraging these weaknesses, often chaining exploits across network edges and VPNs, while defenders struggle with fragmented vendor alerts and outdated risk frameworks. The persistent use of unsupported technology and delayed patching continues to undermine national resilience and exposes critical infrastructure to significant cyber threats.
Timeline
Nov 27, 2025
Cisco warns critical infrastructure is running out of time on legacy tech
Cisco published a report warning that outdated and unsupported technology in national infrastructure is a major enabler for cyber attackers, with the UK assessed as having the highest end-of-life exposure among countries reviewed.
Nov 27, 2025
State-backed groups target critical infrastructure for persistence
By 2025, state-backed actors including Volt Typhoon were described as actively targeting water, energy, and communications networks to establish long-term access.
Nov 26, 2025
Security guidance urges hardening and rapid patching of firewalls
Security experts recommended comprehensive asset inventory, urgent patching, stronger authentication, restricted internet exposure of management interfaces, and monitoring for exploit indicators to reduce firewall compromise risk.
Nov 26, 2025
Research finds most enterprise firewalls fail high-severity checks
Research published in late 2025 found that a majority of enterprise firewalls failed high-severity compliance checks, pointing to governance and operational weaknesses that leave organizations exposed.
Nov 26, 2025
Attacks surge against legacy firewalls across major vendors
In recent months, attacks increased against legacy firewalls from Cisco, SonicWall, Palo Alto Networks, and Fortinet, with some activity attributed to China-linked Storm-1849. Attackers exploited newly disclosed flaws and authentication weaknesses to gain rapid access and persistence.
Jan 1, 2024
Synnovis attack disrupts healthcare services
A 2024 cyberattack on Synnovis disrupted thousands of patient interactions and caused losses exceeding $39 million, demonstrating the operational impact of attacks on legacy-dependent environments.
Jan 1, 2023
US government spends $80 billion maintaining existing systems
In 2023, the US government spent $80 billion on maintaining existing systems, underscoring the financial burden of technical debt and delayed modernization.
Jan 1, 2022
French hospitals still widely use Windows 7
In 2022, about 60% of French hospitals were still using Windows 7, illustrating persistent legacy-system risk in the healthcare sector.
Jan 1, 2020
Global business network assets reach high obsolescence levels
Cisco reported that by 2020, nearly half of global business network assets were already obsolete, highlighting widespread exposure created by unsupported and end-of-life technology.
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