Attackers Hide Behind Trusted Domains, HTTPS

Attackers attempting to dodge more advanced security defenses increasingly are adopting more sophisticated techniques to fool victims with their malicious e-mail messages and websites.

A new midyear report from security firm Webroot found that one in four malicious URLs used a legitimate domain in an attempt to improve the success rate of an attack. In the vast majority of cases — 94% — the attacker used an URL shortener to mask a malicious domain in order for it to appear legitimate. In the first half of the year, the company found 1.5 million phishing URLs, accounting for about one in 50 URLs encountered by its customers.

The overall effect is that users are losing one of the most significant signs of a potentially malicious attack: a URL that appears suspicious, says Tyler Moffitt, security analyst for Webroot.

"Attackers' tactics are reducing (consumers') ability to tell the difference between what is a scam and what is not," he says. "Attackers know that many consumers do a mental check on any domain, and they are trying to fool them."

As companies continue to improve the security of modern operating systems and applications, cybercriminals and online attackers are likewise searching for ways to defeat both software security and fool targeted users. Using trusted domains is one way that attackers are attempting to limit the ability to victims to discern an attack. Another method: employing secure HTTP to give visitors a false sense of security, and nearly a third of phishing domains use HTTPS now.

"[W]hen you see that little lock icon in your browser, it just means that the information you transmit on that site is encrypted and securely delivered to where it's going," Hal Lonas, chief technology officer at Webroot, said in the report. "There's no guarantee that the destination is safe."

In addition, attackers are targeting older operating systems, with malware targeting Windows 7 rising 71%, according to Webroot.

Countries that have older devices tend to have a greater share of attacks, Webroot found. About half of the computers in the most infected regions — the Middle East, Asia and Africa — ran Windows 8 or an older operating system. Computers running Windows 7 were more than twice as likely to become infected than computers running Windows 10, according to the company. 

"While some of these countries have used the technology longer, the key factor is that those which have newer version of the operating system, tend to have fewer infections," Moffitt says. "The main fact is that older devices with older hardware are more vulnerable to attacks."

Over the past decade, attackers have created ways of camouflaging their malware using techniques that create variants to evade signature-based antivirus scanning. The strategy has now become ubiquitous, with 95% of all malware samples encountered by Webroot's software having a unique signature, up from 92% last year, the company said.

Other companies have seen similar trends. Network security firm WatchGuard, for example, saw a significant increase — 64% — in the number of malware variants blocked by its two detection services. The company also saw attacks using content delivery networks (CDNs) to host malware on legitimate-seeming domains.

Two previously popular attacks, cryptojacking and cryptomining malware, have largely subsided as the value of cryptocurrency remains off its peak, but Webroot continues to see attackers attempt to install the payloads as a passive way to monetize otherwise low-value compromises.

"Because they can make money off people's computers by mining, and most people have no idea their system is infected, it continues to be a popular attack," Moffitt says. "It may only be 60 cents a day, but over tens of thousands of compromised systems — that adds up."

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