Dark Reading is part of the Informa Tech Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them.Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Perimeter

9/1/2010
08:30 AM
John H. Sawyer
John H. Sawyer
Commentary
50%
50%

Finding Exposed Devices On Your Network

When browsing through SHODAN, it never ceases to amaze me what I can find. How is it that people think it's okay to leave their printers, routers, fiber channel switches, and industrial control systems completely open to the Internet?

When browsing through SHODAN, it never ceases to amaze me what I can find. How is it that people think it's okay to leave their printers, routers, fiber channel switches, and industrial control systems completely open to the Internet?In case you're not sure what SHODAN is, I've mentioned SHODAN a few times in previous articles and blogs like "Gaining A Foothold By Exploiting VxWorks Vulns." It's been referred to as a rainbow table for Internet-accessible computers because it provides a searchable index of service banners retrieved from HTTP, HTTPS, FTP, SSH, and telnet services on the Internet without the need to do any of your own scanning.

When I was looking at the VxWorks vulnerability, I found vulnerable printers, network switches, fiber channel switches, and industrial control systems (or SCADA) equipment through some simple searches that are mentioned in this blog.

So I'm left wondering who thought it was a good idea to put these devices on the Internet without some sort of protection in place. Is there no change management procedures at these organizations where someone should be monitoring what's taking place on the network? Surely someone has to provision the public IP for use for the devices. Why aren't they asking what the IP will be used for and if the device is being locked down?

Sure, you can use SHODAN to check your netblocks for exposed devices that you might not be aware of, but why not be a little more proactive? Isn't proactive security better than reactive security? Or more to the point, wouldn't you rather find out about a new exposed device on you network before an attacker does?

There are a couple ways to go about this. The first is setting up some simple network scans using Nmap. It could be done daily or weekly, but I wouldn't recommend going as long as a month in between scans. Be sure to set up the scans to save the output to the Nmap XML format. Once you have more than one scan, you can use the Ndiff utility to compare the two scans and determine if there are any state changes for hosts, ports, service versions, operating systems, and the output of scripts.

The Nmap route is cheap and easy to implement, but if you have a nice netflow analysis solution like Lancope's StealthWatch, it can be done even easier. All of the netflow monitoring tools I've seen have an alert option that will notify admins when a new host is seen communicating on the network. I've also seen alerts for when a host begins acting as a server for the first time. For example, if a host is on the network and begins accepting and responding to requests on TCP port 443 for the first time, admins will receive an alert.

Security teams are often the last ones to know when new systems are brought online, but they don't have to be. Using the tools above, security can know when new systems show up on the network and take appropriate actions such as a vulnerability scan, and confirm that the device is authorized and not some rogue wireless router an employee decided to plug in so they could use their new iPad.

John H. Sawyer is a senior security engineer on the IT Security Team at the University of Florida. The views and opinions expressed in this blog are his own and do not represent the views and opinions of the UF IT Security Team or the University of Florida. When John's not fighting flaming, malware-infested machines or performing autopsies on blitzed boxes, he can usually be found hanging with his family, bouncing a baby on one knee and balancing a laptop on the other. Special to Dark Reading.

Comment  | 
Print  | 
More Insights
Comments
Oldest First  |  Newest First  |  Threaded View
COVID-19: Latest Security News & Commentary
Dark Reading Staff 10/23/2020
7 Tips for Choosing Security Metrics That Matter
Ericka Chickowski, Contributing Writer,  10/19/2020
Russian Military Officers Unmasked, Indicted for High-Profile Cyberattack Campaigns
Kelly Jackson Higgins, Executive Editor at Dark Reading,  10/19/2020
Register for Dark Reading Newsletters
White Papers
Video
Cartoon
Current Issue
Special Report: Computing's New Normal
This special report examines how IT security organizations have adapted to the "new normal" of computing and what the long-term effects will be. Read it and get a unique set of perspectives on issues ranging from new threats & vulnerabilities as a result of remote working to how enterprise security strategy will be affected long term.
Flash Poll
How IT Security Organizations are Attacking the Cybersecurity Problem
How IT Security Organizations are Attacking the Cybersecurity Problem
The COVID-19 pandemic turned the world -- and enterprise computing -- on end. Here's a look at how cybersecurity teams are retrenching their defense strategies, rebuilding their teams, and selecting new technologies to stop the oncoming rise of online attacks.
Twitter Feed
Dark Reading - Bug Report
Bug Report
Enterprise Vulnerabilities
From DHS/US-CERT's National Vulnerability Database
CVE-2020-24847
PUBLISHED: 2020-10-23
A Cross-Site Request Forgery (CSRF) vulnerability is identified in FruityWifi through 2.4. Due to a lack of CSRF protection in page_config_adv.php, an unauthenticated attacker can lure the victim to visit his website by social engineering or another attack vector. Due to this issue, an unauthenticat...
CVE-2020-24848
PUBLISHED: 2020-10-23
FruityWifi through 2.4 has an unsafe Sudo configuration [(ALL : ALL) NOPASSWD: ALL]. This allows an attacker to perform a system-level (root) local privilege escalation, allowing an attacker to gain complete persistent access to the local system.
CVE-2020-5990
PUBLISHED: 2020-10-23
NVIDIA GeForce Experience, all versions prior to 3.20.5.70, contains a vulnerability in the ShadowPlay component which may lead to local privilege escalation, code execution, denial of service or information disclosure.
CVE-2020-25483
PUBLISHED: 2020-10-23
An arbitrary command execution vulnerability exists in the fopen() function of file writes of UCMS v1.4.8, where an attacker can gain access to the server.
CVE-2020-5977
PUBLISHED: 2020-10-23
NVIDIA GeForce Experience, all versions prior to 3.20.5.70, contains a vulnerability in NVIDIA Web Helper NodeJS Web Server in which an uncontrolled search path is used to load a node module, which may lead to code execution, denial of service, escalation of privileges, and information disclosure.