A new class of professional cyber criminals has emerged, spanning the ecosystem of attackers, extending the reach of enterprise and consumer threats, and fuelling the growth of online crime.

Symantec's Internet Security Threat Report (ISTR) Volume 21 finds this new breed of cyber criminals is establishing professional businesses and adopting corporate best practices in order to increase the efficiency of their attacks against enterprises and consumers.

“Advanced criminal attack groups now mirror the skill sets of nation-state attackers. They have well resourced and highly-skilled technical staff that operate during normal business hours - they even take weekends and holidays off,” says Kevin Haley, Symantec Security Response director.

“We are even seeing low-level criminal attackers create call centre operations to increase the impact of their scams,” he says.

Advanced professional attack groups are first to leverage zero-day vulnerabilities, using them for their own advantage or selling them to lower-level criminals on the open market.  Once they are available in the open market they are quickly commoditised.

In 2015, the number of zero-day vulnerabilities discovered more than doubled to a record-breaking 54, a 125% increase from the year before, reaffirming the critical role they play in lucrative targeted attacks, according to Symantec.

Meanwhile, malware increased at a staggering rate with 430 million new malware variants discovered in 2015. The sheer volume of malware proves that professional cyber criminals are leveraging vast resources in an attempt to overwhelm defences and enter corporate networks, the company finds.

More than half a billion personal information records stolen or lost in 2015

Data breaches continue to impact the enterprise. In fact, large businesses that are targeted for attack will on average be targeted three more times within the year.

Additionally, we saw the largest data breach ever publicly reported last year with 191 million records compromised in a single incident. There were also a record-setting total of nine reported mega-breaches. While 429 million identities were exposed, the number of companies that chose not to report the number of records lost jumped by 85%. A conservative estimate by Symantec of unreported breaches pushes the number of records lost to more than half a billion.

“The increasing number of companies choosing to hold back critical details after a breach is a disturbing trend. Transparency is critical to security. By hiding the full impact of an attack, it becomes difficult to assess the risk and improve security to prevent future attacks,” says Haley.

Encryption now used as a cyber criminal weapon to hold companies' and individuals' critical data hostage

Ransomware continued to evolve in 2015, with the more damaging style of crypto-ransomware attacks growing by 35%. This more aggressive crypto-ransomware attack encrypts all of a victim's digital content and holds it hostage until a ransom is paid.

This year, ransomware spread beyond PCs to smartphones, Mac and Linux systems, with attackers increasingly seeking any network-connected device to hold hostage for profit, indicating that the enterprise is the next target, Symantec finds.

Don't call is, we'll call you: Cyber scammers now make you call them to hand over your cash

In 2015, Symantec saw a resurgence of many tried-and-true scams. Cybercriminals revisited fake technical support scams, which saw a 200% increase last year.

The difference now is that scammers send fake warning messages to devices like smartphones, driving users to attacker-run call centres in order to dupe them into buying useless services. As people conduct more of their lives online, attackers are increasingly focused on using the intersection of the physical and digital world to their advantage.

From the experts: Security tips and tricks

As attackers evolve, there are many steps businesses and consumers can take to protect themselves. As a starting point, Symantec recommends the following best practices:

For businesses:

• Don't get caught flat-footed: Use advanced threat and adversary intelligence solutions to help you find indicators of compromise and respond faster to incidents.
• Employ a strong security posture: Implement multi-layered endpoint security, network security, encryption, strong authentication and reputation-based technologies. Partner with a managed security service provider to extend your IT team.
• Prepare for the worst: Incident management ensures your security framework is optimised, measureable and repeatable, and that lessons learned improve your security posture. Consider adding a retainer with a third-party expert to help manage crises.
• Provide ongoing education and training: Establish simulation-based training for all employees as well guidelines and procedures for protecting sensitive data on personal and corporate devices. Regularly assess internal investigation teams - and run practice drills - to ensure you have the skills necessary to effectively combat cyber threats.

For consumers:

• Use strong passwords: Use strong and unique passwords for your accounts. Change your passwords every three months and never reuse your passwords. Additionally, consider using a password manager to further protect your information.
• Think before you click: Opening the wrong attachment can introduce malware to your system. Never view, open, or copy email attachments unless you are expecting the email and trust the sender.
• Protect yourself: Prevention is better than a cure. Use an internet security solution that includes antivirus, firewalls, browser protection and proven protection from online threats.
• Be wary of scareware tactics: Versions of software that claim to be free, cracked or pirated can expose you to malware. Social engineering and ransomware attacks will attempt to trick you into thinking your computer is infected and get you to buy useless software or pay money directly to have it removed.
• Safeguard your personal data: The information you share online puts you at risk for social engineered attacks. Limit the amount of personal information you share on social networks and online, including login information, birth dates and pet names.