Have ISP-provided WiFi but don’t think you use it? You could be wrong – and on the open Internet

As with many home networks, you may have an all-in-one cable modem/router/wireless access point provided by the ISP, as well as your own personal router/wireless access point. To prevent a double NAT issue, the ISP router is bridged and the personal router is performing NAT and firewall functions. This setup for a friend’s home network is diagrammed as below:

All wireless devices connect to the Personal-WIFi SSID, with the wireless key saved for automatic reconnection to this access point, and behind the router’s firewall. The ISP-Modem-WiFi SSID was not disabled for the occasional connectivity and bandwidth test. However, whenever he switches to the ISP-Modem-WiFi SSID, he manually enters the wireless key and none of his wireless devices has this wireless key saved. Or so he thought.

About a month ago, he had set his laptop down close to the ISP’s modem in the basement. The laptop was on but was not being used. Later that day, he got on the laptop and noticed he couldn’t connect to any internal sources in his home network but there was internet connectivity. He moved the laptop to the den, and was then able to connect to his media server and file shares. He didn’t think anything of it.

The next day, he discovered for several hours in the previous day, the laptop had had many connection attempts from the internet, several over ftp, telnet, mssql ports. This was alarming because the attempts were coming from the public internet – how were these attempts going through the firewall?

On the laptop runs a HoneyPoint agent – MicroSolved’s proprietary honey pot application – that listens for and responds to connection attempts to specific ports. The agent will then send an alert to the HoneyPoint console for report, alerts or analyses. The laptop HoneyPoint agent had detected these connection attempts. No real service connections were established; no actual breaches occurred. The HoneyPoint agent records the source IP, port being probed, and what data was sent. The attacks indicated discovery probing with a vector towards IoT devices.

But the lingering question was, how could the connection attempts go past the firewall?

It was only serendipitous that he stumbled on the answer. About a week ago, he couldn’t RDP to a Windows box in his internal network, but still had internet. Turns out, the home wifi (Personal-WIFi SSID) was having a hiccup but the laptop had automatically switched to the ISP-Modem-WiFi SSID – outside the firewall. He had inadvertently saved the wireless key to this SSID and was not aware of it. The laptop was now bridged and getting an IP from the ISP, with no firewall or router in between. Also, almost immediately, he noticed the HoneyPoint alerts – connection attempts on the same ftp, telnet, mssql ports were coming in from the public internet.

Lesson learned = if you’re going to keep your wireless access point enabled without a firewall – as in the bridged ISP modem/router – then DO NOT save the wireless key for it on any of your devices (either intentionally or accidentally) or you may be connecting to it without being aware. Best is to disable the wireless, but if you need it, set a strong WPA2 password and do not save the key on any device.

Another lesson learned = In the ensuing troubleshoots, he discovered the router’s uPnP setting had been left enabled, its default setting. That was immediately disabled. Additionally, HoneyPoint agent is a light-on-resources, quick-alerting IDS that does its intended job.

Note of explanation: One could argue the point to bridge the personal router instead of the ISP modem/router, and you would not have this issue. However, if you have many DHCP reservations in your internal network and have ever changed ISP’s, you understand the pain of re-entering those client reservations on a new modem/router. With this setup, you can easily switch ISP’s, slide in a new modem/router and bridge it, and all internal network resources are not interrupted.

Resources: Is UPnP a Security Risk?; Disable This Buggy Feature…

Verifying links before you get phished

Your Mom sends a funny cat video link on YouTube. Your department head sends a link for the training schedule. There’s an email in your Inbox from Amazon for a laptop sale.

Always think twice before clicking on any of those links. Is that email really from Mom or the department head or Amazon? Even if it was really from Mom’s account, is that link really for a cat video on YouTube? Her account, could have been compromised, and the email sent with an obfuscated link.

Phishing works

Phishing campaigns are effective; estimates range from 60 to 90% of all email is a phishing message. MicroSolved’s social engineering exercises have yielded from 11 to 43% success – success meaning recipients have clicked on the benign links in our phishing exercises for clients with their employees. Estimates average 30% of phishing links are clicked.

Obfuscated URL in an Email

So, never click on a link in an email. OK, that may be a little absolute. Only be certain that the link is what you expect it to be. Hover over the link and either a popup or in the status bar of your email client/browser will display the URL. Verify the domain in the link is valid. Simple link obfuscation techniques such as registering a domain named yuotube.com (note the spelling) is an easy phishing and effective trick.

Another trick is hiding the URL behind friendly text, for example, click here. This technique could easily have been used to create a link = stateofsecurity.com – but the the link actually browses to MicroSolved’s home page.

Image links are not immune. That Amazon logo in the email – does that really link to amazon.com? Hover over the link to verify the URL before you click on it. Or better yet, open your browser, type amazon.com in the address bar, then search for and browse to the laptop sale. By the way, don’t browse to yuotube.com, just take my word for it.

Similarly, while browsing or surfing the web, it is always good practice to verify links before you actually click on them. Hover and verify.

Check that browser address bar

So, now that you’ve clicked on that link and landed on the destination web page, are you sure that’s chase.com’s login page? Before you enter your bank account login credentials, check out the URL in the address bar. Make sure it’s https. Any URL that requires you to enter some identification should be over the encrypted protocol, https.

Next, just because the URL has chase.com within it, does not make it a valid chase.com page. Check out the two images below; phishers often trick their victims by obfuscating a URL with a string of an expected valid domain name in the URL:

Note that chase.com is part of the URL, but the login.html page is actually in the badbaddomain.com. The attackers are counting on users to notice the “chase.com” in the URL and click on their link. Once clicked, the user is to taken to a rogue web server with a login page that mimics the real login page for the bank. If the user continues with typing in their authentication credentials, the trap  has sprung – the rogue server has saved the user’s credentials, and the bank account will soon be drained of its funds. Often, after the user enters the credentials, they may be redirected to a valid 404 error page in the user’s bank server, and the user imay be a little confused but unaware that they’ve just given away their credentials.

Current browsers have a feature to help users pick out the actual domain name from the URL – in the top image, the Firefox address bar displays the domain name part of the URL in black font, and everything else in a gray colored font. This is the default behavior; the setting can be changed for the entire URL be the same color format.

Not all browsers display the URL in such a way, Chrome displays the same obfuscated URL as below; the domain and subdomains part of the URL are in black font and the sub-directories and page resource are in grey font:

Shortened URLs

Shortened URLs have become much more popular because of Twitter – it’s a method of reducing a long (regular) URL into a shortened version of usually 10-20 characters. However, because of the condensed URL, it’s not possible to determine the actual address of the link. In this case, it would be wise to copy the shortened URL and validate it with a URL expander website, such as checkshorturl.com or unfurlr.com or unshorten.it.

It’s a minefield out there. Attackers are constantly phishing for their next victim. Be vigilant, beware of what you click, surf safe.

Sources:

https://blog.barkly.com/phishing-statistics-2016