Microsoft: Windows Malware Up, Stuxnet Shell Attack Most Popular

The number of Windows systems worldwide hit with malware infection attempts in the second half of last year jumped by nearly 6% over the previous year to 20%. 

Microsoft’s new Security Intelligence Report (SIR) published today shows vulnerability disclosure was up by more than 9% from June through December of 2015, with some 3,300 bugs reported. “More importantly, high severity vulnerability disclosures were up more than 40%,” says Tim Rains, director of security at Microsoft. “A concerning trend is the increase in vulnerability discovery, thousands every six months.”

As Microsoft revealed last month in a sneak-peek of the ransomware findings in the new SIR, ransomware accounted for a tiny fraction of malware found going after Windows machines—less than 0.5%. Some 0.35% of systems faced ransomware attempts in the first quarter and 0.16% in the second quarter. And, no ransomware family cracked the top ten list of most common malware families spotted going after Windows machines in the second half of the year. Even so, Microsoft says the destructive malware’s use in targeted attacks and as a service is on the rise.

The infamous Angler exploit kit was the number one kit found by Microsoft security tools, and the SIR shows that the Malicious Software Removal Tool cleaned up malware in 0.92% of computers, or 9.2 out of every 1,000 Windows machines.

The new data on security trends in the second half of 2015 draws from Microsoft’s global sensor network of hundreds of millions of Windows systems running Microsoft anti-malware software. The report for the first time taps data from Microsoft cloud security intelligence.

It’s all part of Microsoft’s new strategy of holistic and integrated security across its products and services, a move that Microsoft executives described in detail to Dark Reading in an exclusive interview last fall. Among other things, the software giant invested more than $1 billion in security last year and doubled the number of its security execs, and also launched a managed security services group and opened a cyber defense operations center.

The number one exploit found dogging Windows in the second half of last year: An old and long-patched Windows Shell flaw (CVE-2010-2568) that was first used in the Stuxnet attacks against Iran’s Natanz nuclear facility to sabotage its uranium enrichment program. “It’s been a top one for years and we had patched it in 2010,” Rains says.

The Win32/Gamarue malware family topped the charts; it’s a worm typically spread via exploit kits and social engineering attacks, and is common in southeast Asia and the Middle East, but not in North America nor Western Europe.

Adobe Flash Player objects were the most commonly found object hosted on malicious Web pages, to the tune of 99.5% in the fourth quarater of last year, up from 93.3% in the first quarter. “Almost 100% are just focused on Flash” attacks, Rains says.

The most phishing attacks in the second half of last year were via phishing sites targeting financial institutions.

Not surprisingly, consumers were faced with malware more often than enterprise users, with a 23% encounter rate versus that of enterprises, 11%.

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