Security Experts:

Connect with us

Hi, what are you looking for?


Network Security

Millions of Devices Remain Exposed via SMB, Telnet Ports: Rapid7

Despite being exploited in wide-spread malicious attacks, SMB, telnet, RDP, and other types of improperly exposed ports continue to put both enterprises and consumers at risk, a new Rapid7 report reveals.

Despite being exploited in wide-spread malicious attacks, SMB, telnet, RDP, and other types of improperly exposed ports continue to put both enterprises and consumers at risk, a new Rapid7 report reveals.

Focused on providing an overview of the regional exposure to help Internet service providers (ISPs) worldwide address existing issues, Rapid7’s second National Exposure Index report (PDF) provides information on improperly exposed services and ports rendering systems and user data vulnerable to attacks. It includes data gathered through scanning the web for exposed services, including encrypted and unencrypted protocols, or those meant for public use.

Two of the improperly secured services that continue to make computers vulnerable to attacks are Server Message Block (SMB) and telnet. The former was recently associated with the massive WannaCry outbreak that hit over 160 countries, while the latter has been exploited by Internet of Things botnets such as Mirai, Persirai, or Hajime.

Apparently, there are 5.5 million machines with SMB port exposed, up from 4.7 million prior to May 2017, when WannaCry emerged. The ransomware managed to spread fast via a worm component leveraging the SMB-targeting EternalBlue exploit. Of the total endpoints exposing Microsoft file-sharing services (SMB, TCP port 445), 800,000 of them are confirmed Windows systems, Rapid7 says.

According to Shodan founder John Matherly, over 2 million machines with SMB appear in the device search engine, and most of them (90%) run SMB version 1. He also notes that, while Windows devices running SMB should have been already patched, given that Microsoft released security updates even for unsupported platform iterations, tens of thousands continue to be vulnerable.

Things aren’t better when it comes to devices with exposed telnet (port 23), as there are just under 10 million such devices out there at the moment. Granted, this is a great improvement when compared to the 14.8 million exposed devices discovered last year, but it also means that millions of devices can still fall victim to malware such as distributed denial of service (DDoS) botnets.

The 33% drop seen in the number of exposed telnet nodes is the result of two developments, Rapid7 says. On the one hand, ISPs might have taken stance and started closing port 23 following botnet attacks, while on the other hand the botnets themselves are taking nodes offline to protect themselves from rivals (except BrickerBot, which is only focused on rendering devices unusable).

However, there are other inappropriate services exposed to the Internet as well, including FTP (port 21), RDP (port 3389), PPTP (port 1723), rpcbind (port 111), MySQL (port 3306), and others more. Overall, Rapid7’s scan for these inappropriate services revealed over 90 million nodes.

The company’s report also reveals that Zimbabwe, Hong Kong SAR, Samoa, Republic of the Congo, Tajikistan, Romania, Ireland, Lithuania, Australia, and Estonia are the most exposed countries. When it comes to major cyber superpowers, China and the Russian Federation are among the top 50 most exposed nations, while the United States has “a relatively low exposure in relation to its enormous IPv4 address space.”

Rapid7 chose 30 service ports to scan for their report, but also had a look at two “canary” TCP ports, port 5 and port 61439, which have no well-known service associated with them, thus being unlikely to ever respond to port scanning. However, the company picked up responses from 3.2 million devices from these two ports, and discovered that over 2.3 million IPs (located in 133 countries) responded to both probes.

The report also points out that there are a series of services that have been specifically designed for public use, thus are expected to be exposed to the Internet, although some of them aren’t encrypted, such as HTTP. Many of these, however, are encrypted-by-default, including HTTPS, SSH, IMAPS, POP3S, SMTPS, and FTPS.

The good news, Rapid7 says, is that 3% more nodes are running fewer services compared to last year, partly because of a decrease in telnet exposure. However, the company also believes that “individuals and organizations are beginning to be more careful about what they expose to the world.”

“Server ransomware, ransomworm propagation, insecure Internet of Things, and dozens more headlines reminded us, almost monthly, that the internet is, indeed, a fragile ecosystem that needs deliberate care and attention. Being mindful of both what your organization deploys and how those services are deployed and maintained can have a significant impact on the health of the entire internet,” the company concludes.

Related: Thousands of IP Cameras Hijacked by Persirai, Other IoT Botnets

Written By

Ionut Arghire is an international correspondent for SecurityWeek.

Click to comment

Expert Insights

Related Content


Websites of German airports, administration bodies and banks were hit by DDoS attacks attributed to Russian hacker group Killnet

Network Security

NSA publishes guidance to help system administrators identify and mitigate cyber risks associated with transitioning to IPv6.

Identity & Access

Hackers rarely hack in anymore. They log in using stolen, weak, default, or otherwise compromised credentials. That’s why it’s so critical to break the...

Cybersecurity Funding

Forward Networks, a company that provides network security and reliability solutions, has raised $50 million from several investors.

Application Security

Electric car maker Tesla is using the annual Pwn2Own hacker contest to incentivize security researchers to showcase complex exploit chains that can lead to...

Network Security

Cisco patched a high-severity SQL injection vulnerability in Unified Communications Manager (CM) and Unified Communications Manager Session Management Edition (CM SME).

Cybersecurity Funding

Network security provider Corsa Security last week announced that it has raised $10 million from Roadmap Capital. To date, the company has raised $50...

Network Security

Vulnerabilities identified in TP-Link and NetComm router models could be exploited to achieve remote code execution (RCE).