Which of the following is MOST likely the cause of this issue?

While browsing a website, a staff member received a message that the website could not be trusted. Shortly afterward, several other colleagues reported the same issue across numerous other websites. Remote users who were not connected to corporate resources did not have any issues.

Which of the following is MOST likely the cause of this issue?

A. A bad antivirus signature update was installed.

B. A router was misconfigured and was blocking traffic.

C. An upstream internet service provider was flapping.

D. The time or date was not in sync with the website.

View Answer

Answer: D

Explanation:

A. A bad antivirus signature update was installed – While a faulty antivirus update can cause various issues, it typically wouldn’t result in users receiving a message that websites cannot be trusted.

B. A router was misconfigured and was blocking traffic – If a router was blocking traffic, users generally wouldn’t be able to reach the websites at all. They would likely receive a message that the website cannot be reached or similar, not that the site can’t be trusted.

C. An upstream internet service provider was flapping – ISP flapping (unstable connections) could cause intermittent access to websites, but it wouldn’t typically trigger messages that a website couldn’t be trusted.

D. The time or date was not in sync with the website – SSL/TLS, which is used to secure web connections, relies on certificates that have a valid date range. If a computer’s clock is set incorrectly (either the date or the time), it could result in SSL/TLS certificates appearing to be expired or not yet valid, which would cause the browser to show a message that the site can’t be trusted. This could affect multiple users if a network time server or other time source used by multiple systems in a network is set incorrectly.

So, the most likely cause for users seeing messages that websites can’t be trusted across multiple sites is that their systems’ clocks are out of sync with real time, causing SSL/TLS certificates to appear invalid.