1-855-707-0817 is a fake "Yahoo Support Team" customer service telephone number. The fake support number is being used by cybercriminals to trick potential victims into calling it. If potential victims call the number, the cybercriminals will ask them for their Yahoo account credentials(usernames and passwords). If the requested information is given to the cybercriminals, they will use it to gain access to their potential victims' account, hijack and use them fraudulently.
The cybercriminals may even ask their potential victims to give them remote access to their computers. If they do so, the cybercriminals will secretly steal their personal or even financial information from their computers. Or, silently use their computers to commit other cybercrimes.
A Fake "Yahoo Support Team" Email
From: "Alert" <49761829.CECCB0F29409EF5FFFBFC5oybpgomzclvmptkw @pfxsestnaxvlbtwp.com>
Date: 6 March 2018 at 2:49:28 am AWST
Subject: Your Account Has Been Hacked Call Now
You need to call now 1 855-707-0817
We Have Detected Unusual Activity With Your Yahoo Account
Your Computer and your Private Information Is At Risk
Login Has Occurred on 3/5/2018 @ 5:41 AM EST
From IP: 33.124.12.1 Geo Location Found: Eastern Russia
If This Was Not You Please Call Yahoo Support
1 855-707-0817
Online users who have already called the fake technical support number and who have been tricked by the cybercriminals are asked to change their passwords immediately before their accounts are hijacked and used fraudulently.