A series of spectacular cyberattacks drew headlines this year, and the situation will only worsen in 2015 as hackers use more advanced techniques to infiltrate networks, security researchers said Tuesday.

McAfee Labs' 2015 Threats Predictions report sees increased cyber-warfare and espionage, along with new strategies from hackers to hide their tracks and steal sensitive data.

"Cyber espionage attacks will continue to increase in frequency," the report said.

"Long-term players will become stealthier information gatherers, while newcomers will look for ways to steal money and disrupt their adversaries."

McAfee said small nations and terror groups will become even more active and will "attack by launching crippling distributed denial of service attacks or using malware that wipes the master boot record to destroy their enemies' networks."

At the same time, cybercriminals will use better methods to remain hidden on a victim's network, to carry out long-term theft of data without being detected, the researchers said.

"In this way, criminals are beginning to look and act more like sophisticated nation-state cyberespionage actors, who watch and wait to gather intelligence," the report said.

The report also said hackers are looking to target more connected devices, including computers in the farming, manufacturing, and health care sectors.

"The number and variety of devices in the Internet of Things (IoT) family is growing exponentially. In the consumer space, they are now seen in appliances, automobiles, home automation, and even light bulbs," McAfee said.

- Health care hacks -

McAfee said it is already seeing hackers targeting devices such as webcams with weak security and industrial control systems. But it sees health care as an especially worrisome sector.

"With the increasing proliferation of healthcare IoT devices and their use in hospitals, the threat of the loss of information contained on those devices becomes increasingly likely," the report said.

It noted that health care data "is even more valuable than credit card data" on hacker black markets.

McAfee says other threats will also grow, including "ransomware," which locks down data and forces the victim to pay a ransom to retrieve it, and attacks on mobile phone operating systems.

In the retail sector, digital payments may cut the risk of credit-card skimmers, but hackers may be able to exploit wireless systems such as Bluetooth and near field communications (NFC) used for mobile payments.

"With consumers now sending payment information over a protocol with known vulnerabilities, it is highly likely that attacks on this infrastructure will emerge in 2015," the report said.

The report comes in the wake of news about large-scale cyberattacks that have been linked to Russia or China, and a major infiltration of Sony Pictures which stole massive amounts of data.

In retail, Home Depot and others have reported data breaches affecting millions of customers.

"The year 2014 will be remembered as the year of shaken trust," said Vincent Weafer, senior vice president at Intel-owned McAfee.

"Restoring trust in 2015 will require stronger industry collaboration, new standards for a new threat landscape, and new security postures that shrink time-to-detection."