WannaCry Continues at a Slowed Pace

On Friday, the world was rocked by the largest single-day ransomware attack in history. Late in the afternoon, the first glimmer of good news came with a blog post from MalwareTech who had, without realizing it at the time, stopped WannaCry in its tracks.

The remedy, which exploited a commonly used weapon against ransomware and similar malware, worked because of some lazy coding in the ransomware delivery mechanism. The researcher who brought the attack to a halt admitted in his blog post that an "improvement" to the malicious code was likely and today dawned to the news that the hackers patched their code faster than victims patched their own, and the attack has begun anew.

In truth, there shouldn't be many new systems open to attack today. The vulnerability used by the malware propagation mechanism is known and patched; the digital characteristics of the malware payload are know and have been added to security systems. IT departments around the world have had the weekend to apply one or both levels of update -- vulnerable systems should be few. And yet...

While new infections have slowed dramatically, they haven't completely ended. In a telephone interview with McAfee CTO Steve Grobman, he reported, "From what we're seeing with our customers, things have stabilized. I don't think we're completely out of the woods, but we seem to see a good stabilization."

What was responsible for the stabilizing situation? It seems a combination of factors helped right the heavily listing cybersecurity ship. First, tripping the delivery mechanism's internal "kill switch" bought time for security experts and IT departments to react. Next, many teams used that time to react properly, swiftly applying critical updates to operating systems and installing new malware definitions rapidly developed by security vendors to stop the payloads with firewalls, UTMs and email filters.

With the carnage slowing, attention is now turning to how IT teams can prevent the next episode of "Cyber Armageddon" from hitting their organization. "I think one of the important things we need to do is not to interpret lack of a breach as having a strong defense. That's part of what's made this especially impactful," Grobman said. He added that the impact was magnified because the carrier for the ransomware is a worm, rather than a virus. "What made this spread so rapidly was that one machine could infect other machines by taking advantage of a network vulnerability," Grobman explained.

On the day of the attack, many fingers were pointed at IT departments that had not applied the Microsoft-provided patch that fixed the vulnerability. Enterprise IT professionals quickly protested that the situation isn't that simple: In a complex enterprise environment, any patch or update must be "sandboxed" to rigorously test for any impact it might have on other services or critical enterprise applications.

Grobman agreed with the IT professionals but noted that some were using that "reliability" argument to drag their heels on implementing the patch. "I think enterprise customers need to understand the risk associated with the vulnerability and the risk in applying patches that could have application compatibility issues," he said. "One thing they need to take into account is what types of attack scenarios could be facilitated by the vulnerability. In this case, given that it was a vulnerability that could be exploited remotely, it was a very serious vulnerability and the risk was very high, so enterprises should do everything in their power to fast-track the validation and application."

In the end, WannaCry could end up being a valuable wake-up call for the organizations that weren't successfully attacked. "In many ways we were quite lucky in this case that the impact was limited to organizations that had not patched the vulnerability," Grobman said. "We could see similar events in the future and we shouldn't expect organizations that weren't impacted by this to be safe in the future."

And the ultimate defense might turn out to be a basic process that many don't consider part of traditional security. "We also need to recognize the criticality of a good backup and recovery plan," Grobman said. "We've been advocating for several years to ensure you have your data backed up so when a ransomware incident occurs you have the opportunity to recover your data without paying the ransom."

— Curtis Franklin, Security Editor, Light Reading. Follow him on Twitter @kg4gwa.