How should Black move as to attack all the squares that have no piece on them with only ten legal moves for black? Any unoccupied squares must be attacked. Start from the position above as shown.
Here are the moves:
With OP confirming we can either move up or down the board it can actually be done in 9:
[FEN "8/8/8/8/8/8/pppppppp/rnbqkbnr w kq - 0 1"] 1. null Na3 2. null b1=Q 3. null Bb2 4. null c1=Q 5. null Qb3 6. null d1=Q 7. null Qd8 8. null Qh7 9. null Qcc4
Although Paul Panzer has given the correct solution, I thought it was worth adding another answer because
Even if you assume that black must play up the board you can get very very close (to the point that I'm still not sure if it is impossible).
[FEN "rnbqkbnr/pppppppp/8/8/8/8/8/8 w kq - 0 1"] 1. null d5 2. null d4 3. null d3 4. null d2 5. null d1=Q 6. null Q8d2 7. null h5 8. null h4 9. null b5 10. null e5
Notice here that the only unattacked square is e4 (in front of the pawn) which still seems "half" attacked given it is the only place the pawn can move next.
Also, it is possible to cover this square in one move
11. null Nf6
but you can see that this is close enough that it feels like a different line of attack could make it possible.