Ransomware attack warning signs and how to respond
In 2025, a spree of headline-grabbing ransomware attacks hit major brands — from British retail giants to Adidas and Victoria’s Secret. Shelves sat empty for months, e-commerce sites went dark, and vast troves of customer data were stolen. The brands that recovered fastest were the ones that quickly identified the breach and took decisive steps to secure their systems.
Early detection is far tougher for smaller firms. And with 70% of ransomware incidents in 2025 targeting small- and medium-sized businesses (SMBs), these organisations are the ones most in need of early warning signs to mitigate the threat of ransomware. The impact is disproportionate: one in five SMB victims ends up paying, and six in ten shutter permanently within six months of a serious breach.
This article examines the escalating ransomware threat to small businesses, identifies key warning signs, and provides practical steps to safeguard your business.
Why small businesses are prime targets for ransomware
First and foremost, let’s be clear: the sheer scale of ransomware attacks is on the rise. Reports recorded a 102% year-on-year increase in ransomware incidents in early 2025. And that’s before the spate of high-profile attacks hit the headlines in April.
Driving this boom is Ransomware-as-a-Service (RaaS). These platforms have democratised cybercrime. They provide plug-and-play solutions based on sophisticated AI, as well as customer support systems, so there’s no need for technical expertise to execute sophisticated ransomware attacks at scale. The only barrier to entry is having a sufficiently healthy crypto wallet to pay for the services of RaaS collectives.
So, with all this sophisticated technology, why pursue small businesses? Because the payoff is still rich. Small businesses often can’t afford to weather the downtime and disruptions caused by ransomware, making them much more likely to pay ransom demands. These costs can average from $120,000 to $1.24 million.
That sum might seem like small potatoes compared to the eight-figure ransoms they can reap from major brands, but let’s remember that there are a lot more small businesses. The sophistication of RaaS means cybercriminals can target multiple soft targets, with a greater likelihood of payouts, rather than chasing one big whale.
Modern tactics outpace classic defences
Modern ransomware campaigns are highly sophisticated, thanks to AI, making it difficult for smaller businesses to counter them. Phishing campaigns that often allow cybercriminals access have evolved from emails to sophisticated social engineering campaigns that leverage AI and multiple attack vectors to identify weaknesses.
There’s deepfake-driven voice phishing (vishing), sms phishing (smishing), and even QR code phishing (quishing) to contend with. Many of these attacks are designed to circumvent the traditional phishing detector filters in email inboxes.
Even small businesses are now highly digitalized and reliant on extensive vendor and technology supply chains, which also widens the attack surface. Cybercriminals have exploited supply chain vulnerabilities to target other companies.
Once ransomware attackers are inside a network, their AI-driven tools can swiftly move laterally to attack systems and extract and encrypt sensitive data. The encryption of sensitive data enables cybercriminals to conduct double extortion attacks, where companies are compelled to pay both the initial ransom and additional payments to decrypt the data.
Key warning signs that a ransomware attack is unfolding
Forget what you’ve seen in Hollywood: hacks are seldom fast-paced, edge-of-your-seat affairs. Attackers usually spend days or weeks inside a network. Even so, recognizing early anomalies can significantly shrink the impact and radius of an attack.
Let’s take a look at some of the main warning signs to watch for.
Spotting phishing emails
Generative AI has made malicious emails eerily convincing. In the past, it was often easy to spot cues that an email was malicious. The cues were often deliberately placed to weed out targets that could deduce a ransomware attack was underway. Now, AI enables cybercriminals to closely mimic emails from trusted contacts.
Rather than simply looking out for poorly written emails, you need to look deeper. All unsolicited emails should be checked and verified. Look for unfamiliar sender domains, urgent payment requests, or login pages that feel off.
Files sporting strange new extensions
Many ransomware strains conduct small-scale encryption tests before launching a major attack. If documents suddenly rename themselves to .lock, .r5a, or another abnormal suffix, particularly on shared drives, that’s a clear sign that the file contains malware that could allow cybercriminals to enact ransomware campaigns.
After-hours network chatter
Cybercriminals don’t tend to stick to office hours, so keep an eye on your network’s traffic analytics. Look for activity spikes at unusual hours, particularly outbound activity directed towards obscure IP addresses or internal servers that suddenly scan ports. Both often indicate command-and-control beacons or data exfiltration.
Odd behaviour inside your Active Directory
Repeated failed log-ons from foreign geographies, unsolicited password resets, or new accounts being added to Domain Admins suggest privilege-escalation attempts (attempts by cybercriminals to obtain account privileges that allow access to networks).
Legitimate tools used illegitimately
Attackers favour everyday utilities because defenders overlook them. The surprise appearance of remote access tools where they aren’t authorised should trigger an immediate alarm.
Servers that crawl, then freeze
Encryption routines can significantly stress CPUs and disks, causing them to slow down substantially. If several machines bog down at once, especially outside peak hours, it’s likely live encryption is in progress.
Security tooling that goes silent
Once cybercriminals gain access to a network, a common first step is to disable or tamper with existing cybersecurity measures to enable further access. If your antivirus agents are disabled at random or your logs show sudden gaps, it could be a sign of an attack.
How small businesses can mitigate the threat of ransomware
In an ideal world, all businesses would have access to the most cutting-edge automated cybersecurity defenses on the market. Unfortunately, most small businesses won’t have the budget to take advantage of that.
But there are budget-friendly steps you can take to make your business more resilient to the threat of ransomware.
1. Be prepared before criminals strike
Tackling the threat of ransomware needs to start long before any cybercriminals turn their sights on you and your business.
Many ransomware attacks originate from social engineering and phishing, which means that proper training can be a highly effective defense strategy, even without expensive cybersecurity solutions. Your teams should be trained to spot phishing warning signs and verify unsolicited emails, especially those that request sensitive details.
Teams should also be trained in the proper response plans for when an attack occurs.
On the tech side, regardless of your budget for cutting-edge AI-powered cybersecurity, ensure all aspects of cybersecurity stay up to date with the latest patches. Every day your cybersecurity isn’t kept up to date is a day you’re potentially exposed to cybercriminals.
If you can afford it, maintaining immutable backups stored separately from your network can be a powerful way of mitigating the threat of malicious data encryption: cybercriminals can’t exactly hold your data hostage if you can just spin up a new copy.
You can also explore multi-factor authentication or zero-trust network architectures. These defences add extra layers of verification within your network, reducing the ability of criminals to move laterally and access your sensitive data.
Consider cyber-insurance. Premiums have risen amid the current spate of attacks, but policies now bundle proactive services, such as vulnerability scans and phishing simulations, that harden defenses before disaster strikes.
2. The moment alarm bells ring
When you spot the warning signs of a ransomware attack, isolate any suspected machines or parts of your network to prevent criminals from moving laterally. Make sure you’re tracking everything that occurs and the steps you take, but prioritize containing the problem over perfect record-keeping.
You should contact your Managed Service Provider (MSP) or any external cybersecurity teams you have, as they may have suitable defenses ready to be deployed.
If it comes to the point where you’ve received a ransom request, resist paying as much as possible. Some regions are enacting regulations that would penalize organizations for paying ransomware criminals. Payment is no guarantee of restoration and simply finances future attacks.
Restoring data and restarting systems should only occur after your forensic teams have given the all-clear. Then, you should reset your credentials, audit your firewall rules, and schedule post-mortem reviews to identify and close any gaps that allowed the attack to occur.
3. After the smoke clears
The impact of ransomware attacks can last for months, and you need to be sure attackers aren’t still lurking in your network, waiting to resurface and attack again. You need to enact continuous monitoring for reinfections, conduct regular mandatory password resets, and have a frank debrief with staff.
Being attacked once doesn’t mean it won’t happen again, and you need to ensure your business grows from the lessons you might have learned from the initial attack.
Always be prepared for cyberattacks
Every business, big or small, should treat ransomware readiness as a core business process, no different from cash flow management or health and safety. Small businesses can tilt the odds back in their favour with proper preparation, even without the budget for hyper-advanced cybersecurity.
