Famed security expert HD Moore's latest project — an IT and OT asset-discovery platform that attempts to address the-age-old challenge of finding and fingerprinting devices that reside on an organization's network and their status — just landed $5 million in venture capital funding from some major players in network and security technologies.

The VC round for Moore's Rumble startup was led by Cisco-backed Decibel Partners, via Jon Sakoda and Dan Nguyen-Huu. Other investors include security entrepreneurs Jon Oberheide, co-founder and CTO of Duo Security; Demisto (now part of Palo Alto Networks) founders Slavik Markovich and Rishi Bhargava; Phantom Cyber (now part of Splunk) founder and CEO Oliver Friedrichs; Thinkst Canary founder Haroon Meer; and StoneMill Ventures founder Michael Sutton.

Moore says he built the Rumble Network Discovery tool after years of witnessing firsthand — as a penetration tester and creator of security tools such as Metasploit — that organizations can't properly find, track, and manage IT devices on their networks, nor the security posture of those devices. His years of research scanning for and discovering all types of exposed devices on the public Internet underscored that gap. 

While many security incidents often can be traced to poor visibility into devices on a network, IT asset discovery doesn't fit neatly into security compliance checklists.

That's something Moore admits has been a bit of a challenge in selling the Rumble tool. Since asset discovery isn't necessarily compliance-driven, there's often no budget for it, either, he says. "I love that we have been able to build a thriving business around something that doesn't have a compliance driver — by listening to our users," says Moore, who first launched his startup in the fall of 2019 with the software-as-a-service Rumble Network Discovery platform.

IT asset discovery technology is not new, however. There's the pervasive Nmap open source tool, as well as discovery products from vendors such as Armis, Claroty, Forescout, and Senrio, for example.

One limitation to discovery and mapping tools traditionally has been the need for credentials to access networked devices, so Moore took a different tack that uses network probes to find device MAC addresses and system details on rogue Remote Desktop Protocol (RDP) ports and misconfigured or outdated software on a forgotten system. "As long as it has an IP address, Rumble can track it," he says.

Hidden Weak Links
Sometimes the most painfully overlooked device on a network isn't what you'd expect: A security director at a global manufacturer says while running Rumble his firm found a previously unknown network bridge sitting on its network. He considers Rumble a security tool rather than an IT tool: "If you do not know what you have, how can you defend it?" says the manager, who asked that his company not be named.

Gerry Gosselin, CTO of Pixel Health, found a multifunction printer with its default password still in place when he first ran the discovery tool and began probing the device. "I realized the username was 'admin' and the password was 'admin,'" Gosselin recalls, even though his team previously had been tasked with changing all default passwords in the devices.

And while performing work for a potential client, Pixel Health's managed security service provider arm discovered a previously unknown private network that had been set up by a former employee of the client. "Rumble had already scanned that network and had full asset inventory on" it, Gosselin recalls, which solved a mystery about unidentified network assets that were deleted in a security incident.

To date, Moore says Rumble tracks some 2.6 million network assets and runs around 8,500 scans per day among around 4,100 organizations — 100 of which are on its paid plan and 4,000 on its free-tier service.  

HD Moore

Photo courtesy of HD Moore

2.0
The new 2.0 version of Rumble includes a self-hosted version that can be managed by an organization's cloud provider, and the platform now integrates with both IT operations management platform ServiceNow ITOM and Splunk's security information and event management product.

Among the other new features of 2.0: support for air-gapped networks and automated monitoring tasks, including sending alerts via email or collaboration platforms like Slack, and more APIs.

"The two things that I am most excited about in this release are the new rules engine that drives alerts and asset tagging based on search queries, events, and asset changes, and the new subnet discovery mode of the scan engine, which lets organizations identify all of their private IP space in a reasonable amount of time," Moore says.

The Rumble Network Discovery platform cannot, however, fully fingerprint mobile devices that come and go from the network. "It's mostly an on-prem scanner," notes Pixel Health's Gosselin. "I can't track my mobile devices" with it.

Moore notes that you can scan VPN subnets and remote wireless guest networks with Rumble, but it's not a full mapping. "As long as the devices are reachable by IP, we can generally do something, but the amount of information coming back may be limited," he says.

Meantime, Chris Kirsch, formerly of Veracode and Rapid7, has joined Rumble as co-founder and chief revenue officer, and Mathew Murphy as chief architect.