If the rooms in question are wired for coax you may be able to sneak the ethernet cable down the wall through the existing hole in the top plate of the wall s.
Wiring ethernet through attic.
For single floor homes with a basement the basement may be the best path.
Run the wire or cable to its destination.
Attach the wire or cable to a fish tape or coat hanger using electrical tape and feed it into the hole until it reaches the opening at the other end.
Feeding the wires up and down is usually a 2 person job.
My cable tv is distributed through the attic so it seemed like a good solution to run my home network through there as well.
If you will need to fish wiring through a wall drill a hole through the wood plate in the attic only.
If you re working from the attic you can drop a weighted string down wall cavity then attach the wire to the string and pull it through.
The following links will assist you with your electrical question.
Feed your cables up the wall into the attic space.
You want to run solid cable in the walls attic between your terminations jacks.
Feed the wire through the hole above the distribution box while someone else pulls the from attic.
One person pushes the wire through the origin point and the other pulls through the hole at the destination point.
There are plenty of places online that sell it by the foot or just go buy a spool at lowes depot.
For me my condo is on the 2nd top floor and have access to my attic.
I had to run my cables about 5 inches away for a short section but my network will be fine.
The attic wiring should be protected and secured to ceiling joists or other wood structural supports.
For single floor homes with a basement the basement may be the best path.
And use semi rigid.
For multi story homes you may have to be creative.
Depending on what the wiring is for this may be go through the drywall to the ceiling for instance for new lighting or be farther down on a wall.
Yes this should be corrected and it would be good to have the wiring and all the circuit connections inspected as well.