When visiting the eBay.com site, a script will run that performs a local port scan of your computer to detect remote support and remote access applications. Many of these ports are related to remote access/remote support tools such as the Windows Remote Desktop, VNC, TeamViewer, Ammy Admin, and more. The script being used for fraud detection is further confirmed by Dan Nemec’s great write-up, where he traced it to a fraud detection product owned by LexisNexis called ThreatMetrix.
Source: https://www.bleepingcomputer.com/news/security/ebay-port-scans-visitors-computers-for-remote-access-programs/