How to Mitigate Against Insider Attacks

Posted on Thursday, September 30, 2021

The danger of insider attacks are often overlooked or not given the same level of attention as outside attacks in cybersecurity prevention planning. As insiders already have access to the network and can bypass firewalls, they have an easier task in gaining sensitive information. These threats don’t need to hack through the firewalls first defence to gain access, as they already have access to the network. Has your business got a strategy for identifying and preventing threats from within the organisation? 

Insider attacks are threats to the security of your business taken by a malicious actor who may be an employee or consultant.  This could extend to past or current employees, and range from entry level staff all the way to the board room, or even business partners. A study has shown that there was an increase of more than 30 percent in insider attacks over the past two years. The frequency of these attacks also grew by 47 percent. 

How Insider Attacks Work

To prevent insider attacks you must first understand some of the potential methods they might use in an attack against the organisation. Here are a few of the potential methods insiders can use:

  • Internal Hacking – Malicious attackers may hack their way to corrupt files or into unauthorized parts of the network to gather sensitive data. This could result in data breaches and cause significant damage to the organisation.
  • Mobile & Cloud Storage – This can arise when employees download data onto personal computers or smartphones that they use at home. Due to more homeworking  throughout the Covid-19 pandemic, this kind of threat has been increasing.
  • Email – Email phishing can be used to access data via an untrustworthy link and insiders will have access to all the internal email addresses. They might also have easy access to emails containing sensitive data, which can be misused.
  • Malware – If an employee wants to cause damage to the network they could install malware and ransomware programs onto devices or the internal network.

The Different Types of Insider Threats

As the number of insider attacks grow so does awareness from businesses. In fact, 66% of organisations now believe insider attacks or accidental breaches by staff are more likely than external attacks. Not all insider threats are the same, with both intentional and unintentional damage possible. Here are a few examples: 

  • Careless – The most obvious form of insider attacks is carless unintentional acts that put the organisation at threat. One example could be losing a personal device that has sensitive data on it and allowing that device to be accessed or lost. Another example could be something as simple as forwarding an email thread containing sensitive data to an outside source. 
  • Malicious – While malicious attacks could be perpetuated by anyone in the organisation, most often it’s a disgruntled contractor or employee. They could want to cause damage or even be involved with selling secrets to competitors. 
  • Mole – This is usually someone who gets into the organisation as a high-ranking employee and has access to sensitive information and systems. They aim to gain access for profit or cause serious damage to the organisation.

How to Identify Insider Attacks

Identifying the warning signs of an insider attack is one of the keys to preventing the damage they can cause. Here’s what to look out for: 

  • Unhappy/ Past Employee – Be aware and monitor staff that are unhappy with their current salary, or have left their job. Also look out for those that exhibit dissatisfaction with their position or the organisation. Employees that have displayed suspicious activity on the network are obvious risks.  
  • A Change of Hours – Some employees may change shifts or working patterns in order to get access to sensitive data and avoid monitoring from managers.
  • Activity – Keep a look out for any employees that carry out suspicious activities or who violate corporate policies. Check to see if they have accessed unusual resources within the business. 

Best Ways To Prevent Insider Attacks

Planning for insider attacks is the best method for preventing against them.  By working with a IT company that understands systems and security you can put strategic defence plans in place. This will help to prevent more attacks and minimise the damage that is able to be caused by malicious actors.  Here are the first steps for preventing insider threats:

  • Identify policy weaknesses 
  • Ensure IT security policies are followed
  • Train staff on data safety measures
  • Monitor emails, files, and your data sources 
  • Only give data access to employees that require it 
  • Use security analytics to detect strange behaviours
  • Revoke access to past employees
  • Perform forensics when investigating the issue


It is always difficult to have IT security policies in place when humans are involved, especially when they are inside your organisation.  

The best defence strategies rely on gathering information, monitoring employees for suspicious behaviour, and implementing strong systems and security policies. 


About Mustard IT, your security partner

Mustard IT is a trusted team, experienced in security and able to explain complex issues to you in a language you’ll understand. Contact us today to find out how we can help you.