Every machine connected to the internet is exposed to a constant barrage of communications from tens of thousands of unique IP addresses per day. A percentage of these communications are malicious attacks and web crawls; some are non-malicious scans and pings; some are legitimate business services; and still others are unknown. Taken together, this massive volume of unsolicited traffic is a challenge for security organizations because these communications trigger security tools to generate thousands of events to be analyzed, with little context on the potential threats.
Let’s take a look at the different kinds of internet communications traffic that create this “noise” for security organizations:
Scanning the internet means reaching out and trying to initiate communications with a wide range of devices that are directly connected to the internet. At a technical level, mass scanning the internet means requesting a slight amount of information (specifically a TCP SYN, UDP/ICMP packet, or banner grab) from all 4.2 BILLION IP addresses on the entire routable IPv4 space. And it turns out that tens of thousands of devices are scanning the internet constantly, generating a tremendous amount of internet “noise.”
Good guys scan the internet to measure the exposure of vulnerabilities, take inventory of software market share, and find botnet command & control servers. In fact, there are entire websites and companies that act as "search engines" devoted to mass scanning the internet. Examples of this include companies like Shodan and Censys, as well as researchers and universities, who scan in good faith to help uncover vulnerabilities for network defense.
Bad guys scan the internet with malicious intent to find vulnerable devices that they can compromise and use for nefarious purposes. So while benign mass-scanner IP addresses might check if a port is running and then go away, malicious scanners might attempt to compromise the target machine by brute-forcing login credentials or launching a remote exploit. A good example was a recently discovered vulnerability in F5 network devices - in this case, malicious IPs scanned for F5 BIG-IP devices, checked if the device was vulnerable, and attempted to exploit the vulnerability.
Unknown groups scan the internet for unclear or covert reasons. Unknown actors could be individual researchers, companies, or nation-state actors that are attempting to remain anonymous, and everything in between.
At the end of the day, web crawlers, port scanners, researchers, and malware such as worms and botnets are all part of the activities that contribute to Internet Noise. The challenge for security organizations is differentiating which of these scans are malicious signs of a targeted attack, and which are just “noise.”
Another increasingly challenging source of Internet Noise is legitimate network communications with common business applications like Microsoft O365, Google Workspace, and Slack, as well as services like CDNs and public DNS servers. These applications often communicate through unpublished or dynamic IPs, making them difficult to identify. The result is a storm of log events from “unknown” IP addresses that are, in reality, from well-known and benign business services. Without context, this harmless communication distracts security teams from investigating true threats.
The goal for security teams is to identify malicious internet traffic that represents a potential threat to the organization, so they can focus research and remediation efforts quickly. Internet Noise ends up being a huge tax on SOC teams by taking time away from analysts that could be spent addressing true threats, inflating log volumes and increasing storage costs, and contributing to analyst burnout.
GreyNoise tracks two distinct sets of Internet Noise today, making them available through our API, integrations, and visualizer:
The data GreyNoise collects can be used by security analysts to identify and de-prioritize traffic from omnidirectional scanners and common business services, allowing them to focus on targeted scan and attack traffic. They can use the data to
If you’re interested in learning more about what Internet Noise is and how much of it is happening on the internet right now, please check out the GreyNoise Visualizer. Free to use, the Visualizer can show you:
And if you find this information interesting or useful, please sign up for a free Community account, which includes access to our API for a subset of the “noise” data we collect. Our community of 10,000+ security analysts is a tremendous source of insight into Internet Noise and other InfoSec knowledge. If you are interested in joining, please reach out to firstname.lastname@example.org