Legacy systems are defined as IT systems that are no longer supported by a vendor, or systems that rely on obsolete software where skills are disappearing. These systems are easier for attackers to exploit because vendors have stopped supporting older versions of technology, meaning security patches are no longer released for that version.

Organisations need to be aware of their legacy software and the threat it poses as an attack vector for hackers.

This POV will explore the cybersecurity risks of legacy software and how to address these risks.

Legacy Systems Increase Security Risk

There are multiple ways that legacy software increases security risk for organisations.

Firstly, outdated security functionality does not protect against the growing sophistication of cyber-attacks and hackers. Legacy software can also be incompatible with security features such as single sign on (SSO) and multi-factor authentication. This increases the attack vector vulnerabilities, making cyber-attacks more likely to succeed and detection of these more difficult.

Older technologies can fall short when it comes to integrating newer software, or are unable to handle the increased load of data transfer or additional security monitoring tools, leading to system instability. The instability of integrating new software can result in data siloes and unnecessary security risk.

Another risk is legacy software dependencies. For example, the legacy system may be an ERP system that is integrated with a logistics planning system. This ERP is dependent on the logistics planning system that was installed over five years ago. Because of the dependence, the ERP system is without the upgrades needed to benefit from security enhancements.  Moving to the latest version would break the integrations, but sticking to legacy software will increase organisations attack vectors.

Furthermore, legacy software often lacks the real-time security monitoring that is needed to identify and ultimately resolve security threats. Although the system may monitor performance and outputs, some lack the ability to create an audit trail or  the details needed for full visibility of their security state.

Hidden Dangers of Obsolete Legacy Systems

Aging software can weigh down operations, drain resources, and cause unknown vulnerabilities.

As IT spending becomes more and more decentralised, having oversight of all the systems running becomes a challenge. This is a risk when it comes to maintaining obsolete legacy systems. When administrators move on, and knowledge of the system is lost, they can be left to run in the background, creating a backdoor into the organisation.

Older systems are unlikely to have the capabilities to keep organisations secure due to the inflexibility to expand the software to use said capabilities. This means legacy systems often have security holes that make them easy targets for hackers as they can gain unauthorised access and steal sensitive information.

As regulations are released, legacy systems may no longer meet requirements for privacy and data protection, leaving organisations open to legal and financial consequences. For example, the Data Protection Act 2018 requires all UK data controllers to implement and maintain proper security measures to safeguard personal data. If not followed, organisations can be fined up to £17.5 million and lose brand reputation and customer trust.

Older software also may not be able to quickly respond to audits or alert organisations to attacks due to outdated capabilities, further risking non-compliance and data breaches.

How to Address the Risks

Legacy software becomes a risk when it is not kept secure.

To address security risks, organisations should ensure they update or upgrade their software to the latest version so that they have access to security patches as soon as they become available. Regular patching helps to remove known vulnerabilities that can be exploited by attackers.


Monitoring is key for organisations to ensure their legacy systems fulfil security needs and to detect suspicious activity. Monitoring helps to reduce risks that arise when updating the system is not an option. Monitoring should include security authentication and configuration, and analysing data in real-time for threat intelligence. If organisations are unable to monitor their software efficiently, it is important that they upgrade to a later version that can be properly managed.


Conducting regular security audits is critical to identifying potential attack vectors and ensure that software stays compliant with regulation. An organisation’s cybersecurity audit checklist should consider; operational security which includes policies, procedures, controls, system security covering security patching and account privileges, and data security covering the ways sensitive information moves through a system.


Legacy software or not, it is important for organisations to train their employees regularly to prevent accidental breaches and ensure they know the risks associated with cyber-attacks. For example, understanding data privacy laws and procedures. It is important for organisations to ensure all training is relevant to specific departments, is hands on, and uses simulations or exercises to allow employees to understand where and how to apply their training.


Organisations that are not ready to upgrade, cannot upgrade, or are migrating their software, can receive third party extended support for their legacy software to receive ad-hoc support to maintain functionality. Organisations can utilise third-party development and infrastructure skills when they are needed, or when incidents occur, can receive incident response and recover functionality.


Legacy technology may be running a business-critical service, be obsolete and forgotten, or be running in the background for one small function. In whichever case, the security risks should not be ignored.

Legacy systems create security vulnerabilities that can put organisations at risk of data breaches and other cyber-attacks that can result in legal penalties and loss of reputation. By keeping up to date with updates, modernising software, conducting regular audits, and training employees, organisations can mitigate these cyber risks.

Responsiv and Legacy Security

Responsiv has expertise in keeping legacy systems secure. We have cybersecurity expertise alongside specialist skills in end-of-life software. We can provide extended support, help you to upgrade your software, and consultants that can implement cybersecurity solutions to decrease the risk of cyber threats with monitoring and alerting capabilities.

Case Study: Upgrading IBM API Connect to Manage Risk

A professional services firm had planned a migration from IBM to an alternative technology providers solution. Challenges in the migration project means that they were unable to migrate from IBM API Connect and IBM ACE prior to the software reaching end-of-support. This meant that their Cyber Essentials Plus certification would be at risk, and in turn create a severe business impact.

To address the immediate problem, Responsiv provided extended support for the out-of-date software to reduce the security risk of unsupported software. To upgrade the software to the latest version, a design workshop was conducted to provide detailed runbooks of two upgrade paths. With the preferred path chosen, Responsiv provided a sandbox for isolated API testing and verification. A parallel migration was conducted to reduce the risks of migration, such as production outages.

Responsiv ensures the success of your IBM upgrade project(s) by partnering with your existing teams to understand and solve complex technical challenges and enhance enterprise IT capabilities.

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