Aronica's lazy back pass was intercepted by Gianluca Sansone who rounded Morgan De Sanctis to equalise in the 91st minute and end Napoli's 100 percent home record.
Third-placed Napoli, who failed to capitalise on leaders Juventus' 3-1 home defeat by Inter Milan on Saturday, had led since the sixth minute when Edinson Cavani scored his seventh goal of the season.
Forward Antonio Di Natale, 35, scored his fifth goal in three games to give Udinese a 1-1 draw at Bologna, while Sampdoria slumped to a sixth consecutive defeat, losing 2-1 at home to Atalanta despite a brilliant bicycle kick goal by Enzo Maresca.
Three sides managed to hit four goals during Sunday's games: Catania thrashed Lazio 4-0, helped by two goals from Alejandro Gomez, fourth-placed Fiorentina beat Cagliari 4-1 and AS Roma hammered Palermo 4-1 in the late match.
Juventus lead with 28 points from 11 games, followed by Inter on 27, Napoli on 23 and Fiorentina on 21.
For Napoli, Uruguay forward Cavani returned after missing two games through injury and made an immediate impact as he turned Marek Hamsik's pass into the net in the sixth minute.
On a wet afternoon at a half-empty San Paolo, a sloppy Napoli wasted chances to seal the match, especially when Hamsik rounded Jean Gillet and shot into the side-netting five minutes from time, and paid the penalty.
Coach Walter Mazzarri missed the shambles leading up to Torino's equaliser as he had been sent off for protesting seconds earlier.
Di Natale, Serie A topscorer in 2009/10, 2010/11 and joint third leading scorer last season, kept the goals flowing as his opportunist effort for Udinese wiped out Alessandro Diamanti's close-range goal for Bologna.
He joined Cavani on seven goals, one behind leading scorer Stephan El Shaaraway of AC Milan.
Second-half goals from Stefan Jovetic, Luca Toni and Jose Cudrado gave Fiorentina a convincing win over Cagliari, handing visiting coach Ivo Pulga his first defeat with the Sardinians after winning his first four games.
Gonzalo Rodriguez had given Fiorentina an early lead but Cagliari levelled just before the break in confusing circumstances as Federico Cassarini's goal was first disallowed and then awarded by match officials.
Gomez, one of eight Argentines in the Catania starting line-up, got them off to a flying start when his spectacular left foot strike squeezed into the top corner from a seemingly impossible angle.
Gomez also scored the third and set up the fourth for Pablo Barrientos while Francesco Lodi completed the rout by converting a penalty.