I ran a Clamav virus scan on my games drive and, among the scan results, it said
that the file quake2ex_gog.exe is infected with the unofficial signature Porcupine.Malware.58887.
So I uploaded it to VirusTotal and here's what I got...
https://www.virustotal.com/gui/file/79cef9a57733625e962931808e1aad262fde2b4dd32a2e108ae0c019cf71c2e7?nocache=1

(Although I don't know why VirusTotal labels it ptah.exe)
I invite anyone to upload their .exe file to VirusTotal and see for themselves.

It seems to be a false positive. It happens that some virus scanners will tag legitimate files as being malicious.

I looked in the details column and this file seems to exist under the below names
quake2ex_gog.exe
ptah.exe

There is nothing nefarious going on, the file is completely safe.

VirusTotal shows 1/20+ scanners finds it suspicious, all the others say it's clean.

Also the one that finds it suspicious is guessing based on a heuristic ("AI"), it's not matching to a known signature.

So it is probably a false positive.

A lot of AI heuristics antivirus engines seem to be adding these days "hallucinate" false positives.

An example: a piece of software that is used as a VPN in a legitimate way may be flagged as a backdoor tool for hackers because both employ similar functionalities and an AI can't assess software legitimacy.

Even mainstream AVs known for being overly sensitive with their heuristics didn't suspect anything, according to that results sheet.

Also, VirusTotal itself ran it against ClamAV and it came up clean (at odds with your result). *shrug*

I'd say false-positive, mate.

And if you downloaded it here from GOG, there's a very low chance of the original file containing malicious code. Not impossible, but very unlikely.