US firm Blue Yonder provides software for more than 3,000 customers including Tesco, Morrisons, Sainsbury’s, ASDA, DHL, Proctor & Gamble and Nestle.

The Arizona-based tech firm was hit by a ransomware attack last week and is still struggling to fix the problem.

Blue Yonder customer Morrisons has confirmed it has experienced a significant disruption affecting deliveries to its stores this week as a result of the cyber attack, which comes as the peak shopping season gets under way.

A Morrisons spokesman said the firm had experienced a major disruption and had reverted to a backup process.

The supermarket, which operates almost 500 stores across the UK, said it was working hard to minimize disruption to its food and fresh produce supply chains.

Sainsbury’s said it also experienced disruption to its supply systems this week due to the ransomware attack, which saw it activate contingency plans to manage the system-wide outage. He has now confirmed that services have been restored at the company.

In the US, Starbucks also reported disruptions resulting from the cyber hack.

Not all Blue Yonder customers in the UK were affected. Both Tesco and DHL Supply Chain said this week that they had suffered no problems following the incident.

Blue Yonder uses AI and machine learning algorithms to help retail customers model demand and respond to market changes, optimizing inventory accordingly.

The attack targeted the environment hosted by Blue Yonder’s managed services, which could compromise the inventory management and distribution systems used to maintain food supplies.

As of now, Blue Yonder has not issued a deadline for system restoration.

In a statement, the company said: “Our investigation remains ongoing, but our priority is to ensure a safe and secure recovery.

“The company is working with external cybersecurity experts to investigate and mitigate the impact of the attack.”

Yesterday (November 24), the company said in an update that its teams were “working around the clock” to respond to the incident and were making progress.