Can you attack someone in Gaseous Form?

Gaseous Form
The monster’s body is similar to a cloud of gas, or the monster can take this form. (All of the monster’s gear is absorbed into its gaseous form.) While gaseous, the monster is insubstantial and gains a fly speed equal to its land speed, as well as the ability to hover.

A monster cannot make attacks while in gaseous form unless otherwise noted, but it can move unhindered through porous obstacles that would otherwise prevent movement (such as under a door or through a cracked window).

Insubstantial
When a creature is insubstantial, it takes half damage from any damage source, including ongoing damage. See also half damage.