Cybersecurity in 2026 | Why Out-of-Hours Attacks Are the #1 Growing Threat

The Growing Risk of Out-of-Hours Attacks

When your business closes for the day, your systems don’t. They keep running, connected to the internet, processing data, syncing files and providing remote access to staff and suppliers. For cybercriminals, that’s an open window.

According to the UK Government Cybersecurity Breaches Survey 2025 more than 60% of security incidents now occur outside standard business hours and attackers are deliberately targeting companies when no one is watching.

The same research found that 42% of organisations took more than 12 hours to detect or contain an overnight breach.

Out-of-hours attacks are not new, but the scale and speed of them in 2026 have made this one of the most urgent cybersecurity challenges facing UK businesses.

This trend is especially visible in ransomware activity, where according to the 2024 Ransomware Holiday Risk Report by Semperis, 86% of ransomware victims were targeted on a weekend or holiday. Attackers know that the slower your response, the higher their success rate.

However, the level of protection your business needs will always depend on the type and volume of data you handle.

Organisations managing sensitive or high-value information face greater risks and many larger partners or suppliers now require proven security standards before they will even consider working together.

And while every business is different, one constant remains: attackers are evolving faster than most security setups can keep up.

Continuously improving your defences through regular reviews, staff training, simulated phishing exercises and proactive testing is essential to stay ahead. This is an area where you can reach out to us to review your current setup, identify potential risks and get tailored guidance on strengthening your organisation’s protection.

Why Out-of-Hours Attacks Are Rising

Hackers don’t just attack overnight, they prepare for it. During the day they collect data, study company websites, mimic supplier emails and gather credentials from leaked databases or social engineering attempts.

Attackers gather intelligence throughout the day when staff are busy or recovering from a long shift and may be less vigilant, using social engineering, credential harvesting and probing to map access points.

By the time the business closes, they already have the access points they need.

And the actual breach then happens when no one is watching.

Out-of-hours their tools take over. They test stolen passwords against your systems, probe for unpatched software and attempt to bypass security controls in silence. AI has made this even easier. Automated attack kits can now run continuously, scanning for weaknesses and executing attacks without human involvement. Once a vulnerability is found the attack begins instantly, leaving businesses very little time to react.

This combination of human reconnaissance during the day and automated execution overnight is what makes out-of-hours attacks such an effective and growing threat.

Out-of-hours breaches typically exploit four key weaknesses:

1. Ransomware Deployment
   Attackers often gain access days or even weeks before launching ransomware. Once inside, they quietly disable backups, delete security logs and plant encryption scripts that activate over weekends or holidays when IT staff are unavailable.
   
   
2. Credential Stuffing and Brute Force Attacks
   Automated bots test thousands of stolen passwords from previous breaches against company logins. These attacks often run overnight because they rely on persistence rather than speed. Without active monitoring, repeated failed logins can go unnoticed for hours.
   
   
3. Exploiting Unpatched or Exposed Systems
   Old VPN configurations, forgotten remote access tools and outdated software create ideal entry points. When updates are delayed or endpoints aren’t monitored, attackers exploit these known vulnerabilities during quiet hours.
   
   
4. Phishing and Social Engineering
   Phishing campaigns are often sent early in the morning or before work hours, catching employees checking emails on personal devices. A single click can give attackers the credentials or foothold they need to return later with a larger, coordinated attack.

In every case, the attackers are betting on time. The longer it takes to detect and contain an intrusion, the greater the potential impact on your business.

The Impact of Overnight Breaches

When a breach begins at midnight and isn’t discovered until morning, the outcome can be catastrophic. Hours of uninterrupted access allow attackers to move through networks, encrypt data and disable backups before anyone even realises something is wrong. By the time the team logs in, systems can already be locked, data lost and recovery costs mounting.

Delayed detection is one of the most underestimated risks for UK businesses. In many cases, encryption begins within minutes of the initial compromise, while detection can take several hours, which is enough time for a "small issue" to become a full-scale operational crisis.

The financial and reputational impact of these incidents can be severe. Vodafone Business estimates that cyberattacks cost UK SMEs more than £3.4 billion each year, and according to the UK Government’s Cybersecurity Breaches Survey 2025, the average cost of the most disruptive cyber breaches for UK businesses is £8,260 per breach.

The scale of impact can also vary depending on the kind of data your organisation manages. Businesses handling sensitive client records, payment information or intellectual property often face more severe consequences, not only from data loss but from the reputational and contractual implications that follow.

In many industries, companies are expected to meet minimum security standards and failing to do so can limit partnerships or disqualify bids altogether.

But the difference between discovering an attack in five minutes or five hours is not just cost, it’s continuity. Lost productivity, client disruption, reputational damage and regulatory fines can follow long after systems are recovered.

There is, however, a clear link between proactive security and reduced risk.

We know that businesses following recognised standards are significantly less likely to suffer an attack.

According to the NCSC’s latest findings, organisations that achieve Cyber Essentials certification are 92% less likely to need to make a claim on their cyber insurance.

Frameworks like Cyber Essentials build strong cybersecurity discipline, enforcing patch management, access control and staff awareness that help prevent small vulnerabilities from becoming major breaches.

However, that is just the tip of the iceberg. At The HBP Group we work with you to identify what disaster recovery means for your organisation. Together we can map out the systems that matter most, discuss the recovery time you need and create a plan that fits the size, structure and goals of your business.

Understanding what kind of disaster recovery approach is right for you can make the difference between a short disruption and a serious long-term impact. If you are not sure where to start, reach out to our team who can guide you through the process and help you build the right level of protection for your business.

The Human Factor

Technology can only do so much. The truth is that most cyberattacks still start with a human action, such as clicking a link, downloading a fake attachment or approving a login request that looks legitimate.

According to the UK Government’s Cybersecurity Breaches Surveys, phishing remains the most common cyberattack affecting UK organisations, with 93% of businesses and 95% of charities experiencing phishing attempts in 2025, up from 84% the year before. It’s clear that despite stronger technology, people remain the first and most frequent point of failure.

Human error is one of the main reasons after-hours attacks succeed. The best way to reduce this risk is through education, awareness and consistent reinforcement.

You can take a deeper dive into this topic in our related article, Why Employees Are Still Your Biggest Cyber Risk, which explores how culture, training and leadership can help reduce human error.

You can also find practical, free awareness resources here: Free Cybersecurity, Phishing, Passwords & Social Engineering Training

What can You Do Today?

If you can do one thing today, we suggest you review your after-hours monitoring and your ability to detect and contain activity when the office is closed. However, that is just the start.

There is so much more to think about when it comes to protecting your business from cyber threats. At The HBP Group we work with you to understand your organisation, identify risks and build the right level of protection across every area of your cybersecurity.

Understanding what kind of recovery and protection approach is right for you can make the difference between a short disruption and a serious long-term impact.

If you are not sure where to start, you can read our article How Businesses Can Strengthen Their Cybersecurity to explore practical ways to build resilience, or get in touch with our team and we can work with you to understand your needs.