2023/05/04

Multiple vulnerabilities in Zyxel NBG-418N V2

As part of Fitsec's service offering our labs conduct device audits and research to find new vulnerabilities that might affect our customers. Fitsec's labs come across a wide variety of devices, ranging from consumer products to enterprise devices. In the past, these have included devices such as utility grid monitoring (electricity & water), routers, smartphones and even engine control units (ECU).


During December 2022 we had an internal training session where the objective was to find vulnerabilities in common IOT devices.

For this purpose we purchased a few units of Zyxel NBG-418N V2 home routers, as they were on the low-end in terms of price and features, which makes them popular for consumers and small businesses alike.

To begin with, we first dumped the firmware from the internal Macronix EEPROM chip. We reverse engineered the bootloader in order to gain access to the actual code that was being run in the device.



After dumping, UART connection was also established to capture logs.
We were able to discover 5 unique vulnerabilities in the target device:

  • XSS (Cross-site scripting) in the web management interface
  • Persistent XSS in the web management interface
  • Kernel stack overflows in the CLI (Command Line Interface) app
  • Kernel format string vulnerabilities
  • Denial of service condition (kernel crash and reboot)


The first issue was already known by Zyxel, but the other 4 were new vulnerabilities.

Based on our findings and reporting, Zyxel has released a firmware update and a security advisory. In case you have a vulnerable device in use, we recommend updating the device to the latest firmware.

https://www.zyxel.com/global/en/support/security-advisories/zyxel-security-advisory-for-multiple-vulnerabilities-in-nbg-418n-v2-home-router

2023/05/01

LEAN 365 – grab the cyber security tips of April

During April we shared a total of 30 cyber security tips in LinkedInTwitter and Instagram.
Here is a compilation of the posts. Jump in together with Fitsec – and stay cyber safe!


91. It’s a good idea to password protect personal documents containing sensitive data

WHY? 

Even if your device is compromised, the data in these documents will be harder to access

92. Before giving away your phone, do a factory reset

WHY? 

A factory reset erases all your information from the device

93. Don’t use your car’s audio system for sensitive phone calls

WHY? 

In most cases the audio can easily be heard outside the car 

94. Never connect your own device to your organization’s network without approval

WHY? 

Your device may compromise the safety of the network and your company

95. Disable auto filling your account details on any websites

WHY? 

If your device is compromised, the attacker will automatically have access to your accounts

96. Beware of scams during major holidays

WHY? 

It’s common to offer “special deals” during major holidays, make sure that the offers are legitimate

97. On Windows machines, make sure Autorun/Autoplay features for media are turned off

WHY? 

It prevents external media infected with malicious code from being automatically executed

98. Make sure your Wi-Fi has strong password protection

WHY? 

Having a weak password on your Wi-Fi network makes it easier to attack

99. Install apps on your phone only from official sources (Google Play, Apple Store etc.)

WHY? 

Apps from official sources have been verified and are usually safe

100. If your printer supports secure printing, use it

WHY? 

Secure printing requires you to be present at the printer, thus making sure that no one can see your documents

101. Don't use passwords that contain your personal information, like date of birth

WHY? 

This makes your password easier to guess and your account more vulnerable

102. Don’t share your property information on the internet

WHY? 

Sharing your cabins etc. location or other information is not recommended and can lead to theft of your property etc.

103. Use a credit card for online purchases

WHY? 

If you get scammed, you can dispute the charge and get your money back

104. Don’t use admin account for everyday tasks

WHY? 

Using a regular user account will give less privileges to a possible attacker

105. Don't store sensitive data in the cloud; keep it entirely disconnected from the web

WHY? 

Keeping your sensitive data offline and requiring physical access keeps your data safe

106. If your device has a webcam, use a privacy cover. A piece of tape works just fine.

WHY? 

On some occasions, the webcam may be activated without an indicator light

107. Only connect with people you know on LinkedIn

WHY? 

In addition to giving more information about yourself to strangers, criminals have been known to use this extra information to attack other people as well

108. Exercise your right to be forgotten

WHY? 

Online services and companies in general, may otherwise retain your data indefinitely

109. Shred your old bank and credit cards

WHY? 

This makes them unusable, and it is near impossible to gather any data from a well shred card

110. You should turn off Windows timeline from privacy settings

WHY? 

The Windows timeline/activity history has to keep a lot of information about you to work and sends this information to Microsoft by default, turning it off is an easy way to gain more privacy

111. When taking a screenshot on your device, always double-check the picture before sharing

WHY? 

Using a regular user account will give less privileges to a possible attacker

112. Don’t trust any popups on websites that claim you have malware and prompt you to download an antivirus or call a number

WHY? 

This is a common method to get you to download malicious software on your device

113. Think twice before trusting free apps

WHY? 

Non-governmental free apps often make their money by selling personal data. Avoid giving any permissions related to data access if a free app asks for it

114. Never access your email or accounts on a device that you don’t own

WHY? 

It helps to prevent account hijacking and prevents leaking your information to a third party

115. Try to read news about new cyber attacks/scams

WHY? 

This might inform you of new ways hackers could be attacking you and help to keep you safe

116. Disable background webapps from your browser settings

WHY? 

Some apps might keep running even when you close your browser. This setting prevents them from doing so.

117. Be careful when taking or sharing workplace photos

WHY? 

There might be something in the background that could reveal/leak information that is private

118. If you are an EU citizen you have the right to ask for all the data that a company has about you

WHY? 

European union GDPR (General Data Protection Regulation) states that a person must get a copy of the data about them when asked

119. Periodically check which devices are logged into your account if the service has such an option

WHY? 

If there is a new device that you don't recognize, your account may have been compromised

120. Make sure your phone is always locked when you are not using it

WHY? 

It helps to protect your data in case your phone gets stolen





2023/04/01

LEAN 365 – grab the cyber security tips of March

During March we shared a total of 31 cyber security tips in LinkedIn, Twitter and Instagram. Here is a compilation of the posts. Jump in together with Fitsec – and stay cyber safe!


60. You should have remote data wiping/factory reset enabled on your mobile device

WHY?

If you lose it or it gets stolen, you can wipe all information from your phone to prevent unauthorized access to your data

61. Never share your PIN code or password to anyone

WHY?

You have no way of knowing who can ultimately get access to your password. Passwords and PIN codes are sensitive information and should be protected.

62. If you make a mistake and open a phishing email or suspicious attachment, don’t hesitate to notify your IT/security team immediately

WHY?

A quick response to an incident may prevent any damages or at least minimize the impact on your organization

63. Make sure your employees only have access to assets that they need

WHY?

Giving your employees unnecessary access will cause more damage if they are compromised

64. Prefer your phone’s hotspot over public Wi-Fi

WHY?

Using your own hotspot is more secure than public Wi-Fi 

65. Make sure your desk is clean and doesn’t have sensitive documents on it when you are not present

WHY?

You never know who can have access to the documents 

66. Deny location sharing by default

WHY?

There is rarely a good reason for services to access your location. Limiting the amount of information you share is always a good idea. 

67. Think twice about what information you share about yourself when creating a new profile to some new service

WHY?

Some services may enable unauthorized third parties to collect this information about you

68. Keep in mind that any operating system can be infected by malware

WHY?

A common mistake is to assume that only Windows based systems are targeted by malware

69. Avoid public phone charging stations

WHY?

Malicious actors have been known to target public charging stations to infect your device

70. Before disposal, shred documents that contain personal information

WHY?

An unauthorized third party with malicious intent could get hold of your personal data and use it to harm you in numerous ways

71. Factory resetting a mobile device usually removes active malware on the device

WHY?

Most malware do not persist after a factory reset

72. Beware of marketplace scams. Never send money upfront when dealing with second-hand goods

WHY?

There are plenty of scams in used item marketplaces that take advantage of an unsuspecting buyer

73. You should use full disk encryption on your computer

WHY?

If your computer is stolen, your data is protected

74. Separate your work accounts from private ones

WHY? 

Using your work accounts for personal activities may endanger your organization’s security and may also result in losing access to your private accounts if they are tied to your work email for example 

75. Report phishing emails or other suspicious emails to your helpdesk/security team 

WHY? 

Reporting phishing emails helps protect your organization

76. Do not leave your personal belongings in plain sight in your car 

WHY? 

Your car will be more likely to be targeted by criminals 

77. SMS is not a secure messaging service

WHY?

There are multiple methods to capture SMS messages

78. Keep your devices turned off when not using them

WHY? 

There are many benefits to this, for example, when your device is turned off it is safe from network-based threats

79. Check your bank transactions regularly

WHY? 

This may show if somebody has access to your accounts

80. Don’t use actual personal information when answering security questions

WHY? 

If the answers to security questions have nothing to do with you, it will be more difficult for an attacker to guess them

81. Disable NFC on your device when not using it

WHY? 

NFC allows your phone to transfer data if it touches another NFC device

82. Always remember to logout of your accounts when you’re done

WHY? 

It’s simply a good practice that keeps you safer

83. If you’re connecting to a public Wi-Fi, make sure it’s the right one

WHY?  

It’s a common attack method to have a similar name to the actual Wi-Fi and use that to steal your information (for example: Starbucks-wifi vs Starbucks_WIFI etc.)

84. Remember to update the firmware of your devices periodically

WHY? 

Updating the firmware of your devices helps to keep them secure

85. Does your fridge or washing machine etc. really need an internet connection?

WHY? 

IOT devices often suffer from multiple vulnerabilities and may compromise your network

86. Do not share photos of your keys 

WHY? 

Certain types of keys can be cloned with just a photo of the key

87. Do not use public printers to print sensitive documents 

WHY? 

Some printers may save a copy of the file on an internal drive

88. When shopping online, search for reviews of the website before you place an order

WHY? 

Reading the reviews can tell you if the site can be trusted

89. Use encrypted email for exchanging sensitive data

WHY? 

Regular email is not encrypted by default

90. Disable auto connecting to Wi-Fi networks

WHY? 

Your device might automatically connect to a Wi-Fi that is pretending to be the intended Wi-Fi. This attack is called the Evil Twin attack.






2023/03/01

LEAN 365 – grab the cyber security tips of February

During February we shared a total of 28 cyber security tips in LinkedInTwitter and Instagram. Here is a compilation of the posts. Jump in together with Fitsec – and stay cyber safe!


32. Be cautious of who might see your computer screen when travelling or working in public. To help with this, use a privacy screen protector.

WHY?

All information is worth something to someone if the person seeing it has bad intentions

33. Protect yourself from phishing: Use common sense and do not open suspicious emails, always doubt!

WHY?

Someone can try to pose as an authoritative or well-known entity and exploit this to obtain information that can be used to steal money or cause other harm

34. From time to time clear your cookie cache in your browser settings

WHY?

Over time, cookies accumulate a wealth of information and can be used to for example track your browsing history and personal data

35. Always question messages that prompt you to act urgently - if you are not completely sure of the legitimacy of the sender and/or the message content, double check the legitimacy directly with the person supposedly contacting you (for example in person or by phone)

WHY?

Often scams tend to rely on conveying urgency, which leads to mistakes being made. You can never be too careful.

36. More sensitive activities like online banking should be avoided on devices that you don’t own

WHY?

You can’t be sure what software is installed on the device and your information may be compromised as a result

37. Always follow your organization's information security guidelines

WHY?

When all personnel work together as agreed it is easier to keep your organization secure

38. Use good judgement and common sense when downloading files from the internet. It is a good idea to scan the downloaded file with your antivirus product.

WHY?

There is an increased risk of malicious code being run on your computer when opening files downloaded from the internet

39. The best place to store your passwords is in your own memory: use memorable passphrases to help with this

WHY?

It is simply the safest solution

40. Keep your backups in a safe place, like in a trustworthy cloud service or a safe

WHY?

Without backups, you might lose some important information for good

41. Be careful not to reveal your personal identity information to anyone. Carefully destroy all the material containing this kind of information when you don’t need it anymore.

WHY?

Identity theft can lead to any number of problems for you. Your identity could for example be used to take loans in your name and you will be responsible for them.

42. Remember to read the reviews before trying a new app: If there are many complaints about its functionality or if every review is praising the app, carefully consider before using it

WHY?

Malicious apps are not that uncommon and are frequently found on legitimate marketplaces (google play, apple app store etc.). Creators of these apps can also source fake reviews of their apps to entice new users to download them.

43. It is a good idea to use incognito mode/private window when browsing the web on public/shared computers

WHY?

It prevents the next person using the same computer from accessing your browsing history and information related to it

44. Memorize or write down your bank’s deactivation service number

WHY?

In case your credit card is lost, or your bank account is compromised, you can quickly call to lock it

45. Delete unused accounts

WHY?

They could still contain sensitive data and you wouldn't even notice if they are compromised

46. Buy devices from known manufacturers

WHY? 

Off-brand devices generally have more security flaws and are not usually kept up to date

47. Always use a VPN when you are connected to a public Wi-Fi network

WHY? 

Unsecure public networks might give an attacker access to your sensitive data

48. Don’t plug in unknown USB devices to your computer

WHY? 

Unknown USB devices may harm your computer

49. Do not leave data protection material lying around unattended. The material should always be stored in the places designated for them, e.g. in a safe, fire safety cabinet or in a locked box/cabinet, depending on the sensitivity of the material.

WHY?

Because you can't be sure who has access to them otherwise

50. Take advantage of password managers, they generate unique and strong passwords and keep them safe

WHY? 

This makes it easier for you, so you don’t have to remember all of them

51. Don’t use auto login features. Always have some form of login authentication on your devices.

WHY? 

If your device is stolen and does not have a password/pin code, the thief will have immediate access to your device

52. Remove or destroy the hard drive from broken devices before disposal

WHY? 

You have no way of knowing where your device is going to end up after disposal. Even fully broken devices might have data left on the hard drive.

53. Remember that if something seems too good to be true it probably is

WHY? 

Many scams try to lure you with amazing prizes and offers

54. If you need technical support, use the official website of the vendor/manufacturer

WHY? 

A common scam is to target users of popular software and devices via fake support websites

55. Purchase tickets to events from official ticket vendor websites

WHY?  

Criminals often create fake websites and target consumers looking for deals. These websites steal your payment information and personal details.

56. If you are not using a password manager, update your passwords frequently. It is recommended to change passwords every 90 days.

WHY? 

If a service you use is compromised, there is a better chance of your account being safe

57. Don’t google search your own bank or other sensitive services. Type the URL directly in the search bar.

WHY? 

Criminals often target these types of services by advertising fake websites that look just like the real ones. These fake websites are then used to capture your login details and personal information.

58. Be mindful of what you put out on the internet 

WHY? 

What you put on the internet will stay there forever

59. Avoid software that is not supported or updated anymore

WHY? 

Unsupported/older software won't be updated with the latest security patches and could be vulnerable. This can ultimately lead to your device being compromised.





2023/02/01

LEAN 365 – grab the cyber security tips of January

During January we shared a total of 31 cyber security tips in LinkedIn, Twitter and Instagram. Here is a compilation of the posts. Jump in together with Fitsec – and stay cyber safe!


1. Do not give any sensitive information over the phone

WHY?

Someone might be spying

2. If possible, use multi-factor authentication for all services

WHY?

To ensure that you and only you have access to your account


3. 
When you stop using your phone and sell it or give it away, make sure to do a factory reset and remove all attached cards (sim and memory cards).

WHY?

Otherwise, someone else might get access to your information


4. 
Do your employees have a direct channel to report security incidents or risks? Has the channel been announced to all employees?

WHY?

When using an easy and direct reporting channel, the ability to quickly react to security incidents improves substantially.

5. Always dispose of all physical (paper) data protection material properly - by burning, shredding or using a data security bin.

WHY?

To prevent sensitive material ending up in the wrong hands


6. Make sure your VPN is always on when you are working outside the company premises

WHY?

Public networks cannot always be considered safe

7. Before giving away (for destruction), overwrite your computer hard drives 3 times

WHY?

To ensure that no one can restore your information


8.
Only use your work email for work matters

WHY?

Using your work email for personal communications might endanger your organization's cybersecurity

9. If an email contains a link, do not click on it or copy it, but write the address in the address bar of the browser itself. (EVEN IF the sender seems trustworthy!)

WHY?

Otherwise, you cannot be sure where the link leads

10. Use passphrases, not passwords

WHY?

Because they are easier to remember, but harder to guess or crack

11. If you notice any concerns or shortcomings in the security practices of your organization, make sure to report it to your supervisor.

WHY?

Shared responsibility helps minimize risks

12. Use numbers and special characters in passphrases

WHY?

To make them harder to crack or guess

13. When receiving an email, check the sender’s email address

WHY?

Do not trust just the name, also check the email address and be certain of who you’re dealing with

14. Remember to take backups regularly

WHY?

This way you can make sure your information is saved, even if something happens to your device


15. Do not open attachments from unknown senders

WHY?

You cannot be sure, what the attachment contains and it could be malicious


16. Do not give your login information to anyone

WHY?

Because it is always possible that they end up in the wrong hands


17. Remember to always lock your computer when you leave your desk

WHY?

So that no one can access your information or do anything malicious while you are away

18. 3-2-1 -method: Always keep at least 3 copies of your data: 2 on different devices and 1 in a separate service.

WHY?

If one place with your data would be destroyed, you still have two copies intact

19. Keep your device and software updated to the newest version with the latest security updates

WHY?

Regular updates ensure you are prepared for the newest cybersecurity threats in the best possible way

20. The ideal length of passwords should be at least 14 characters – containing both upper and lower case letters + numbers and special characters.

WHY?

To make them harder to crack or guess

21. Dispose of electronic data protection material as carefully as physical material - the file itself should be overwritten 3 times. 

WHY? 

Because just deleting the file does not ensure that it cannot be restored


22. Use a safe way to share files, like a trustworthy cloud service with sufficient encryption

WHY?

For example emails with attachments might end up in the posession of third parties


23. Use your work computer only for tasks related to your work, not for your personal activities

WHY?

Your personal activities may result in infecting your work computer with malware, and possibly your organization overall

24. It is not a good idea to share your travel plans and current location on social media posts

WHY?

These types of posts let criminals know you are not at home and have been used to commit burglaries

25. Think twice about what you post on social media and who can view your post 

WHY?

You may end up sharing potentially sensitive information to unwanted third parties


26.
Make sure to continuously educate your employees about the latest cybersecurity threats

WHY?

Keeping your employees up to date with current threats helps to strengthen your defences


27. You should consider using automatic data backups. They are usually a built-in, optional feature on your device.

WHY?

Because it saves time and increases the reliability of your backups


28. Do not use the same password in many places

WHY?

If someone gains access to your login info, only one of your accounts is compromised


29. Do not download illegal copies of software or other media, no matter how harmless it seems

WHY?

They often contain malware and your device along with your information will be compromised


30. Notify your company's information security officer of any anomalies, for example, where you see information on the company's network that you shouldn't actually see.

WHY?

Cybersecurity is a collective effort and individual observations can help strengthen your security posture

31. Always change the default credentials after receiving a new device with pre-set credentials

WHY?

Because attackers can easily find/guess the default credentials and compromise your device