Thousands of UK businesses have been secretly targeted by a security infection that has gone undetected for at least 11 months, security firm Seculert has reported.
Dubbed 'Magic Malware' the attack features several detection dodging capabilities.
"This ‘Magic Malware' is active, persistent and had remained undetected on the targeted machines for the past 11 months. Since then the attackers were able to target several thousands of different entities, most of them located in the United Kingdom," wrote Seculert's Aviv Raff.
The malware's reportedly infects businesses systems using a specialised server communication protocol.
Its command and control server (C&C) is able to then instruct infected machines to carry out a range of tasks, such as remotely accessing infected machines or networks.
Raff said that the purpose of the advanced malware is currently unknown, though it is likely designed for espionage rather than outright sabotage.
"The real intention of the attackers behind this magic malware is yet to be known. As the malware is capable of setting up a backdoor, stealing information, and injecting HTML into the browser, we believe that the current phase of the attack is to monitor the activities of their targeted entities," wrote Raff.
The Seculert researcher said there is evidence suggesting the malware is still a work in progress warning it may only be the first stage in a wider operation.
"This persistent threat is still under development. We have seen several indications of features which are not yet implemented, and functions which are not yet used by the malware," wrote Raff.
"Because this malware is also capable of downloading and executing additional malicious files, this might be only the first phase of a much broader attack."
Senior research fellow at ESET, David Harley, agreed with Raff, calling for businesses to double check their security systems to prepare for the next stage of the attack.
"It seems that right now the focus of the malware seems to be on gathering information from affected sites. That could be for a number of reasons: financial targets suggest direct profit, but education and comms providers could be targeted for other motives, for example, used as a stepping stone in an attack against other entities," said Harley.
"To protect themselves, businesses should take the usual steps of checking that systems and applications are patched, security software is updated, and ensure that users are educated into being more resistant to social engineering."