The Ugandan international was reported to be headed to Ibrox but the player and his club Gor Mahia's chairman have rubbished the rumour.
Aucho will need a visa to play in Scotland but is to join up with the Dons on trial.
Soka25east.com describes Aucho as a player with "agility, physical power and prowess, speed, [a] lethal left foot and above all amazing composure as most of Gor Mahia attacking revolves around him".
And the forward told the East/Central African football website: "I just read a lot about Rangers but the truth of the matter is that I have been invited by Aberdeen and not Rangers.
"I have applied for the visa and just waiting to get it before I travel to Scotland for my trials."