What is a good opening to play against the caro-kann?

What is a good opening to play against the caro-kann? I've noticed that some of my opponents on this site mostly play the caro-kann and I don't know why. I also don't know how to play against it. Is caro-kann common in 500 elo? or did it suddenly gain popular

It's popular because a lot of youtubers promote it as a very safe beginner opening. There are a lot of good variations against the Caro Kann.

I would recommend the Panov Attack if you like open, attacking positions.

It also changes the structure completely from a normal Caro Kann. Caro players will be used to this Caro structure with pawns on c6 and e6 but the Panov enters an IQP structure.

This is an example line. The idea is to open up files and diagonals for your pieces and attack.

The Advance variation is also very strong and good if you like closed positions. I would recommend the Tal variation as a lot of Caro players have difficulties against this line.

Another strong variation to consider is the Fantasy variation. A lot of Caro players struggle against this variation as it's very aggressive while Caro players are typically looking to play their safe, passive structure.

White can generate a lot of initiative in these lines and black can easily get into trouble.

There are a lot of ways things can go very wrong for black from this position if they don't know their stuff. White is way ahead in development and can use the semi-open F-file in an attack.