Did you just run into a file that has a digital signature from Tesline-Service s.r.l.? If so, please read on.
You'll typically notice Tesline-Service s.r.l. when running the file. The publisher name shows up as the "Verified publisher" in the UAC dialog as the screenshot shows:

You can view the additional details from the Tesline-Service s.r.l. digital signature with the following procedure:
Here's a screenshot of a file that has been digitally signed by Tesline-Service s.r.l.:

As you can see in the screencap above, Windows reports that "This digital signature is OK". This means that the file has been published by Tesline-Service s.r.l. and that no one has tampered with the file.
If you click the View Certificate button shown in the screencap above, you can view all the details of the certificate, such as when it was issued, who issued the certificate, how long it is valid, and so on. You can also view the address for Tesline-Service s.r.l., such as the street name, city and country.
GlobalSign CodeSigning CA - SHA256 - G2, GlobalSign ObjectSign CA and GlobalSign CodeSigning CA - G2 has issued the Tesline-Service s.r.l. certificates. You can also examine the details of the issuer by clicking the View Certificate button shown in the screenshot above.
These are the Tesline-Service s.r.l. files I've gathered, thanks to the FreeFixer users.
| Detection Ratio | File Name |
|---|---|
| 1/71 | rhdisk_amd64.sys |
| 1/57 | agent.exe |
| 1/66 | agent.exe |
| 1/66 | ntserv.exe |
| 0/44 | rhdisk.sys |
| 0/44 | agent.exe |
| 0/55 | agent.exe |
| 0/56 | ntserv.exe |
Here is the detection names for the Tesline-Service s.r.l. files. I've grouped the detection names by each scanner engine. Thanks to VirusTotal for the scan results.
| Scanner | Detection Names |
|---|---|
| Bkav | W64.HfsAdware.1409, W32.HfsAdware.6E81, W32.HfsAdware.1409 |
The detection percentage is based on that I've collected 459 scan results for the Tesline-Service s.r.l. files. 4 of these scan results came up with some sort of detection. You can review the full details of the scan results by examining the files listed above.
In the analysis on this page I grouped all certificates where the signer name is set to upper and lower case variants of Tesline-Service s.r.l.. These are the signer names:
The analysis is based on certificates with the following serial numbers: