Security researchers have uncovered a bug that could allow attackers to deliver malware directly into employees’ Microsoft Teams inbox.

“Organisations that use Microsoft Teams inherit Microsoft’s default configuration which allows users from outside of their organisation to reach out to their staff members,” Jumpsec researcher Max Corbridge explained.

With a social engineering pretext to prime the target, a malware delivery attack exploiting this vulnerability has a considerable chance of success.

Malware attacks hit a new zenith within the last few months as criminals ramp up their assaults on targets around the world.

The latest quarterly McAfee Labs Threat Report revealed that the number of malware samples reached an all-time high, with 57.6 million new samples recorded within the three months covered. This is equivalent to four new samples being recorded every second, and represents a 10 per cent rise on the previous quarter alone.

Mobile malware also saw a major rise, with the report revealing a total growth in mobile to hit 21.1 million samples – a 60 per cent increase from the previous quarter, a rise largely due to a rapid increase in Android screen-locking ransomware.

“Although attackers will always seek ways to use newly developed innovationsand established platforms against us, our industry perhaps faces a greater challenge in the effort to influence individuals and organisations away from becoming their own worst enemies,” said Raj Samani, McAfee’s chief scientist.

Overall, McAfee Labs encountered 263 publicly disclosed security incidents in Q3, a decrease of 15 per cent from the previous quarter. The firm added that more than 60 per cent of all publicly disclosed security incidents in the quarter took place in the Americas.

The health and public sectors accounted for more than 40 per cent of total incidents in Q3 2017, with health sector attacks growing in North America, and public sector attacks topping the list of reported attacks in both Asia and Europe.

Elsewhere, ransomware attacks also saw a significant increase, with new ransomware samples rising by 36 per cent during the quarter, hitting 12.2 million samples. This was helped by the emergence of Lukitus, a new version of the Locky ransomware which hit more than 23 million spam emails within the first 24 hours of its release.

The British security researcher who helped stop the NHS-crippling malware attack earlier this year has pleaded not guilty to hacking charges in the United States.

According to his lawyers, Marcus Hutchins, from Devon, will “vigorously defend himself” and be “fully vindicated” when his case goes to trial.

He was arrested in Las Vegas and charged with developing Kronos – malware allegedly designed to steal banking logins and other financial information – in early August.

The case is unrelated to the WannaCry attack that struck the NHS and 300,000 computers around the world in May, for which Mr Hutchins gained worldwide attention after he detected a “kill switch” that effectively disabled the virus.

Mr Hutchins has been released on conditional bail with a $30,000 (£23,000) cash bond which was provided by “a variety of sources”, according to his former attorney Adrian Lobo.

He will now be represented by Brian Klein of law firm Baker Marquart and Marcia Hofmann of Zeitgeist Law.

Speaking outside the court, Ms Hofmann said: “Marcus Hutchins is a brilliant young man and a hero.

“He is going to vigorously defend himself against these charges and when the evidence comes to light we’re confident that he will be fully vindicated.”

Strict bail conditions were modified to allow Mr Hutchins to use a computer for work, having been banned from using the internet at an earlier hearing.

He can also now travel around the US and live in Los Angeles, so he can be near his legal team ahead of his trial in October.

Mr Klein said: “We are very pleased today that the court modified his terms allowing him to return to his important work.”

The researcher was previously urged to do a deal by supporters who feared the conditions he could be imprisoned under in the US.

Microsoft’s security team is urging developers to shore up their software update systems – after catching miscreants hijacking an editing application’s download channels to inject malware into victims’ PCs.

In a security advisory, Redmond’s infosec gurus describe Operation WilySupply: their mission to find, isolate and destroy an unusual and highly targeted form of malicious code that was hiding in the software update mechanism of a widely used, and unnamed, editing tool.

Microsoft thinks that the attackers found a flaw in the application’s upgrade system that allowed them to send unsigned updates to Windows machines to install. A 132-byte binary called ue.exe was dispatched to some victims’ computers: this fired off PowerShell scripts and Meterpreter to fetch and run the Rivit trojan.

This wasn’t the usual spray-and-pray malware attack. The initial infection via this update channel was highly selective and only affected specific computers run by finance and payment companies. After it had delivered the payload, the ue.exe program instantly deleted itself to avoid detection.

“While the attack itself, including the selection of targets, appears to have been carefully planned, the attacker toolset comprised commodity tools and simple malware,” the advisory states. “These commodity tools are the same tools used in typical penetration testing exercises.”

Microsoft believes the purpose of the attack was to siphon organizations’ cash into crooks’ pockets, which would account for the camouflage techniques. The Windows giant has now added routines to detect similar infections to its operating system’s antivirus tools.

However, it’s going to be up to software developers to truly lock down this method of attack. Redmond recommends fully encrypting supply channels, enforcing code signing, perhaps adding two-factor authentication for critical stuff, and checking logs frequently.

Business managers striving to protect their organisations from cyber attacks should keep an eye on software piracy.

A 2015 IDC analysis of Business Software Alliance (BSA) survey data found that malware incidents rose alongside unlicensed software use: In the United States, the rate of quarterly malware encounters in 2013 trailed the rate of unlicensed software use 13 percent to 18 percent, respectively.

Jodie Kelley, BSA’s senior vice president and general counsel, says the connection between malware and piracy is only natural.

“When you have people putting non genuine software on the market to download for free or at an incredibly reduced price, it is not surprising that these bad actors could be embedding malware in it,” she says.

But counterfeit applications aren’t the only danger to organisations. “Even if the software is genuine but not licensed, then you might not be getting the security patches, so that is another avenue for malware to get into a system,” Kelley says.

Although these risks make software management essential for businesses of every size, Amy Konary, a research vice president at IDC, says having a high volume of software applications can make the task particularly “daunting” for larger organisations.

She recommends that IT leaders proactively address the problem by combining employee education with software asset management (SAM) tools and best practices.