Ferdinand was left with blood pouring down his face following the incident at the end of Manchester United's dramatic 3-2 win over local rivals Manchester City, and police are trying to find out who threw the 2p piece at the defender.
The player himself tried to play down the incident, sarcastically praising whoever threw the coin for their accuracy but adding that "it could at least have been a pound coin".
But the Daily Mirror reported that Ashley Cole's family reacted with jubilation to the attack on Ferdinand, who was reprimanded for labelling Cole a 'choc ice' over the John Terry racism affair earlier this year.
Cole was criticised by an FA independent commission for the "evolution" of his evidence in defence of Terry who was accused of racially abusing Ferdinand's brother Anton.
The comments were allegedly started by Ashley's brother Matty, who reportedly posted on Facebook: "So happy Rio got hit in the face when he tried to give it kissing his badge!! Straight in the eye!! Made my day."
The boys' mother Sue Cole is said to have replied, saying: "Bloody missed that, ha ha ha," then adding, "Give the fan that threw it a medal!"
The paper claims that Sue Cole then added, "wonder if he can see????" when Ferdinand appeared in the audience at the X-Factor later that night.
But when the Daily Mirror called Sue Cole for comment, she denied making the posts: "Who has put that on? I don't know who has done that. It wasn't me," she said, adding that any jibes against Ferdinand were "disgusting".
The offending posts were removed five minutes after the reporter called, the Mirror claims.