DNS-Messenger

We’re used to hackers using conventional attack strategies, so, although we can defend these, it means hackers are looking for more discreet attack methods.

And, just recently, hackers have been looking to exploit routes in and out of our PCs which are not usually monitored for malicious activity. It makes sense for hackers to seek out these poorly defended access points as, for hackers, the best hack is an easy hack.

For businesses, though, it raises a lot of questions on just how in-depth and conscientious your security efforts need to be; in order to help you understand the situation and nature of these attacks, I’m going to discuss the DNSMessenger threat.

DNS as a Means of Attack

The Domain Name System (DNS) is the method by which the domain name of a website, computer or network is converted into an IP address which is a numerical code that can be recognized by PCs e.g. one of the many IP addresses for Google is 74.125.224.72

Now, as DNS helps PCs to communicate with many other systems, it provides a very useful route for hackers to breach defenses. Thankfully, it’s very difficult for hackers to hack directly into the DNS channels, but by using a malware exploit they can gain access. And it’s all part of a trend in the evolution of malware.

Users are prompted to download an MSWord document – containing malicious code – through an email phishing campaign which sets the attack in motion. The malicious payload is written in the Powershell language which permits administration tasks to become automated. It’s at this point that the hackers can identify user privileges and plan the next step of the attack which utilizes the DNS.

Using the DNS, hackers are able to send commands directly to the user’s system and effectively have free rein over that system. What’s particularly deceptive (and clever) about this attack method is that it’s very difficult to monitor; few systems monitor DNS traffic and Powershell operates purely in the system’s memory rather than relying on external files which are easily identifiable.

Combatting DNS Attacks

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Whilst there are niche software solutions that can help protect businesses from DNS attacks, the simplest solution is by educating your staff on the telltale signs of malware and phishing:

  • If you do not recognize an email address then, under no circumstances, click on any links or files contained within it. And, even if you do recognize the sender’s email address, run a quick audit on the email’s content as the sender’s account could have been hacked – badly worded and poorly formatted emails are often a sign of hacked emails.
  • The DNSMessenger attack is only able to unleash its payload once the infected Word document is opened and the recipient clicks on the pop up window prompting them to “Enable Content”. By enabling the content, the recipient is unwillingly giving permission for their system to be hacked, so always treat this request with suspicion.

These preventative methods are fairly simple, but, due to the volume of emails people receive these days, there doesn’t seem to be the time to carry out these quick checks. However, with hackers taking their attacks in new directions which are incredibly difficult to monitor, a few seconds thought could save your systems from a nasty attack.

For more ways to secure and optimize your business technology, contact your local IT professionals.

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TP-Link is among the vendors affected by the SOHO pharming campaign.

Recently, it was discovered that several hundred thousand routers fell victim to a hijacking scheme that could become a prevalent problem to many internet users worldwide.  The attack, dubbed as a ‘small office/home office (SOHO) pharming campaign,’ was targeting Vietnam, but according to a report by Team Cymru, the SOHO pharming campaign also made its way into regions like the US and Italy.

The criminals behind the pharming campaign took advantage of exploitable security holes in various consumer-grade routers, and from there they were able to redirect users to malicious websites to steal login credentials and/or dropped malware onto the users’ computer.  The scary part about this SOHO campaign is that more than one type of routers are affected.  According to Team Cymru, the compromised routers could be a brand name like D-Link or and off-brand like TP-Link.

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A diagram depicting the ‘man-in-the-middle’ hijacking scheme from Team Cymru.

Cyber security experts found that once the attackers had control of their targeted routers, they changed the devices’ Domain Name System (DNS) settings to force users to send out requests to the 5.45.75.11 and 5.45.75.36 IP addresses.  The new DNS settings then acts as a ‘middle-man’ and redirect users to malicious sites instead of legitimate ones.

While it is easy to point the fingers directly at the people manufacturing the routers, it’s not completely their fault.  There’s no such thing as a ‘hands-off’ policy when it comes to protecting yourself from intrusions by cyber criminals.  That said, there are a few things many router owners can do to lessen their chances of becoming victims to the router hijacking scheme.

  1. Disable router’s remote user-mode and graphical user interface. Disabling remote access will help keep users who aren’t directly connected to your network from accessing your routers’ admin properties.  Disabling the GUI will, reportedly, mitigate the likelihood that someone can find a hole in the routers’ software.  Instead of making changes to the routers’ setting via a graphical interface, try to change the settings via command lines.
  2. Corporate networks may want deploy tracking systems (i.e. an HTML code on the externally facing servers) to detect possibly malicious IP addresses.
  3. All SOHO router settings (especially DNS) should be controlled at the host level.
  4. Admins must proactively monitor router settings periodically to ensure that the router’s DNS is pointing at those that belong to their internet service providers (ISP).

These are just a few of the basic security measures you must consider if you or your organization is using a SOHO router.  Should you have any questions or concerns regarding the recent SOHO pharming campaign or what you should do tighten up your network security, contact our IT professionals.

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