ASICs do dominate Bitcoin mining but Monero's POW algorithm is supposed to be ASIC resistant. Besides, who cares if it's efficient when it's someone else's server?

Monero's proof of work (RandomX) is very asic-resistant and although it generates a very small amount of earnings, if you exploit a vulnerability like this with thousands or tens of thousands of nodes, it can add up (8 modern cores 24/7 on Monero would be in the 10-20c/day per node range). OPs Vps probably generated about $1 for those script kiddies.

This is the PoW scheme that Monero currently uses:

> RandomX utilizes a virtual machine that executes programs in a special instruction set that consists of integer math, floating point math and branches. > These programs can be translated into the CPU's native machine code on the fly (example: program.asm). > At the end, the outputs of the executed programs are consolidated into a 256-bit result using a cryptographic hashing function (Blake2b).

I doubt that you anyone managed to create an ASIC that does this more efficiently and cost effective than a basic CPU. So, no, probably no one is mining Monero using an ASIC.

Yes, for Monero it is the only real viable option. I'd also assume that the OP's instance is one of many other victims whose total mining might add up to a significant amount of crypto.

Its easily worth it as they are not spending any money on compute or power.

If they can enslave 100s or even 1000s of machine mining XMR for them, easy money if you set aside the legality of it.

Hard for it not to be worthwhile, since it’s free for them. Same automated exploit run across the entire internet.

Optimal hardware costs money. Easy to hack machines are free and in nearly unlimited numbers.

When your cost per host is $0, even $5 / mo / hacked host profit can make for an ok business

If the effectiveness of mining is represented as profit divided by the cost of running the infrastructure, then a CPU that someone else is paying for is worth it as long as the profit is greater than zero.