How to tell if your company is under attack: 10 Signs you shouldn’t ignore

A cyberattack doesn’t always start with ransomware locking every device or a screen warning that your data has been encrypted. In many cases, the first signs are much less obvious: a login from an unexpected location, an account downloading an unusually large amount of information, or connections between systems that are not part of normal activity.

The problem is that a company can generate thousands of logs and activity signals every day, and not all of them look suspicious at first glance. Without proper monitoring, an intrusion can go unnoticed while a cybercriminal gains access to more systems, accounts, or information.

The question, therefore, is not just whether your company has security tools in place, but whether it can detect a cyberattack in time and take action before it affects business operations.

How Can You Detect a Cyberattack Before It Infects Your Entire IT Infrastructure?

Waiting for a system to stop working or for a ransomware message to appear means detecting the attack once its effects are already visible. By then, the cybercriminal may have had time to access other accounts, move through the network, or locate valuable information.

How can you detect it in time? By monitoring what is happening across your infrastructure, analyzing behavior that deviates from normal activity, and correlating different signs of suspicious activity. Early detection can help identify a potential attack, reduce the attacker’s window of opportunity, and contain the incident before it affects more systems or information.

10 Signs Your Company Could Be Under Cyberattack

1. Logins Appear From Unknown Locations or Devices

A login from a country where your company does not operate, from a device the user does not recognize, or at an unusual time could indicate that an account has been compromised.

It does not necessarily mean an attack is underway, but it should be investigated when the login does not match the user’s normal activity.

2. An Account Starts Accessing Resources It Does Not Normally Use

A compromised account can be used to access applications, folders, databases, or cloud services that the user does not normally need.

If an account starts accessing information or systems outside its usual activity, reviewing its permissions and the context of those accesses can help detect an intrusion before it progresses.

3. Large-Scale Downloads or Data Transfers Occur

A sudden download of large amounts of files could indicate that someone is collecting information to remove it from the environment.

Monitoring who downloads the data, which device they are using, and how much information is being transferred helps distinguish legitimate activity from behavior that requires investigation.

4. A Device Starts Connecting to Systems It Does Not Normally Use

When an attacker gains access to a device, they may try to use it as a starting point to reach other computers and servers.

Unusual connections, attempts to access multiple systems, or the use of credentials to access new resources may indicate movement within the network that does not match normal activity.

5. Accounts Are Created or Permissions Are Changed Without a Known Reason

Creating new users, changing passwords, or modifying privileges can all be part of normal business activity.

However, when these changes have not been authorized or occur alongside other suspicious behavior, they may indicate that someone is trying to gain a higher level of access to your systems.

6. Security Tools Appear to Be Disabled

Cybercriminals may try to disable antivirus software, security controls, or logging mechanisms to make their actions harder to detect.

That is why a security control that stops working, a configuration that changes without authorization, or a security service that appears disabled should be investigated.

7. Systems Start Behaving Abnormally

A sudden slowdown, unknown processes, or unusually high resource consumption can have many different causes.

However, when these changes appear alongside other security signals, they may indicate that a device or server has been compromised. Monitoring can help identify these changes and correlate them with other signs of suspicious activity.

8. Network Connections Appear That Do Not Match Normal Activity

Corporate devices constantly connect to internal and external services. New or repeated connections may require investigation when there is no known explanation for them.

Analyzing network traffic and connections can help identify communication patterns that may indicate malicious activity.

9. Backups Show Unexpected Changes

Modifying, deleting, or encrypting backups can be part of an attack, particularly when the goal is to make it harder for the company to recover afterward.

That is why having backups is not enough. They must also be protected against unauthorized changes and monitored for activity that does not match normal operations.

10. Multiple Warning Signs Appear at the Same Time

A single anomaly does not prove that a cyberattack is taking place. The risk increases when different behaviors start occurring together.

For example, a login from an unexpected location followed by a large-scale data download and connections to other systems provides a very different context from any of these signals analyzed individually.

Correlating these signals makes it possible to identify patterns that could go unnoticed when each alert is analyzed separately.

What Should You Do If You Detect Multiple Warning Signs at Once?

Detecting a potential intrusion does not mean you should act without a plan. The priority is to contain the incident, determine its scope, and prevent it from spreading further.

A company should:

• Isolate affected systems to limit communications from a potential threat.
• Review and secure compromised accounts, especially those with elevated privileges.
• Preserve logs and evidence related to the incident to support the investigation.
• Identify which systems and data may be affected and prioritize actions based on their impact.
• Activate the incident response procedure and assign responsibility for coordinating the incident.
• Assess notification requirements when the incident affects personal data or other systems subject to specific regulatory requirements.

Your response should be prepared before an incident occurs. Improvising while an attack is already underway can delay critical decisions needed to contain it.

Could Your Company Detect a Cyberattack Before It Becomes Visible?

A secure company is not one that never experiences an attempted attack. It is one that knows what is happening across its systems, identifies suspicious behavior, and has the ability to respond when a threat is detected.

Reviewing these warning signs can help identify gaps that may otherwise go unnoticed in day-to-day operations: unmonitored logins, accounts with excessive permissions, uncontrolled data transfers, systems that are not being monitored, or security tools that stop working without anyone taking action.

The key is to move from a security model based on reacting when a problem appears to one that combines prevention, continuous monitoring, and response.

At ESED, we help organizations strengthen this capability through managed cybersecurity services, continuous monitoring, threat detection, endpoint protection, vulnerability management, and incident response, all for a fixed monthly fee with no hidden costs.