My fellow penguins,
I have been pwned.  What started off as weeks of smiling everytime I heard a 7-10s soundbyte of Karma Factory's "Where Is My Mind" has now devolved into hearing dashes and dots (Morse Code) and my all-time favorite, a South Park S13: Dead Celebrities soundbyte of Ike's Dad saying, "Ike, we are sick of you talking about ghosts!"
It's getting old now.
I feel like these sounds should be grepable in some log somewhere, but I'm a neophyte to this.  I've done a clean (secure wipe >> reinstall) already, the sounds returned not even a day later.
Distro is Debian Bookworm.  So how do I find these soundbytes?  And how do I overcome this persistence?  UFW is blocking inbound connection attempts everyday, but the attacker already established a foothold.
Thank you in advance.  LOLseas
Update:  post-reinstallation and monitoring incoming connections, I'm happy to say the sounds have not returned.  This has given me the motivation to install a Netgate 1100 with pfSense ahead of the PC.  Thank you all!
Get a carbon monoxide detector
I'm fiiiiiiiiiineeeeeeeee. I have one. Made me smile nevertheless. Thanks!