Definitely just aphids. Soap or diatomaceous earth work as noted (though they do wash off, so they need to be reapplied after rain).
It's important not to over-fertilize any plant with aphids cause then their populations really explode. Also, for small populations like this, you can just knock them off the plant with a spray of water, a paintbrush, or my personal favorite: a cordless air duster (basically a hair dryer with no heat and a nozzle). Just knock them off every day for a week, and they should all be gone.
Don't put them close to other plants, though.




