▁ 4 4 5 ▁as ▁well ▁as ▁un sol ic ited ▁U DP ▁packets ▁to ▁ports ▁above ▁ 1 0 2 4 . ▁Additionally , ▁Windows ▁XP ▁Service ▁Pack ▁ 2 ▁dis ables ▁the ▁M essen ger ▁Service ▁by ▁default . ▁ ▁M essen ger ▁Service ▁sp amm ers ▁frequently ▁send ▁messages ▁to ▁vulner able ▁Windows ▁machines ▁with ▁a ▁URL . ▁The ▁message ▁promises ▁the ▁user ▁to ▁er ad icate ▁sp am ▁messages ▁sent ▁via ▁the ▁M essen ger ▁Service . ▁The ▁URL ▁leads ▁to ▁a ▁website ▁where , ▁for ▁a ▁fee , ▁users ▁are ▁told ▁how ▁to ▁disable ▁the ▁M essen ger ▁service . ▁Though ▁the ▁M essen ger ▁is ▁easily ▁disabled ▁for ▁free ▁by ▁the ▁user , ▁this ▁works ▁because ▁it ▁creates ▁a ▁perce ived ▁need ▁and ▁then ▁offers ▁an ▁immediate ▁solution . ▁ ▁Sp am ▁D ete ction ▁in ▁Op in ion - based ▁Re comm ender ▁System ▁In ▁opinion ▁based ▁recomm ender ▁system , ▁an ▁important ▁concern ▁is ▁how ▁to ▁evaluate ▁the ▁user - generated ▁reviews ▁on ▁the ▁items . ▁One ▁of ▁the ▁purpose ▁of ▁this ▁evaluation ▁is ▁to ▁identify ▁mal icious ▁or ▁sp am ▁reviews . ▁Po or ly ▁written ▁reviews ▁are ▁considered ▁hel pl ess ▁to ▁the ▁recomm ender ▁system . ▁However , ▁even ▁if ▁a ▁review ▁is ▁well ▁generated , ▁they ▁can ▁still ▁be ▁harm ful ▁to ▁the ▁recomm ender ▁system ▁by ▁their ▁bi ased ▁pre jud ice ▁to ▁form ▁an ▁actual ▁advert is ement ▁or ▁s land er ▁towards ▁a ▁target ▁item . ▁ ▁Current