"People don't have a malware problem. They've got an adversary problem," says George Kurtz, CEO and co-founder of CrowdStrike. Last week at the Cybersecurity Summit in New York, Kurtz presented a case study of how Hurricane Panda and other organized cybercrime groups are attacking systems without using malware -- which makes them far more difficult to detect -- and how to combat them.

In lieu of malware, says Kurtz, attackers are manipulating legitimate tools like PowerShell and conducting surreptitious intelligence gathering using one-line web shells like China Chopper. This helps them blend in with regular users -- the bigger the user base, the harder it is to detect them.

According to Kurtz, organizations need more visibility into what's happening across their computing environment. Instead of just looking for "indicators of compromise" -- like malware infections, command-and-control traffic, or data exfiltration -- they need to start looking for "indicators of attack."

For example, instead of just watching for malware, companies need to watch for any sort of executable that's out of the ordinary and then dynamically respond to whatever seems suspicious. Kurtz describes it as "hand-to-hand digital combat" with an adversary.