Robert Bowling has just revealed that Modern Warfare 3 received a hotfix that will prevent players from exploiting the proficiency exploit.
Earlier today, we reported on the possibility of proficiency exploit being hotfixed instead of waiting for patch 1.08 to be released. Luckily, Infinity Ward has released a hotfix to address the problem. Bowling stated that the security team has “released a hotfix for Modern Warfare 3 which prevents users from exploiting the ‘Damage Proficiency’ glitch.” Unlike patches (title updates), hotfixes are pushed at any time without the need go through the certification process by console manufactures. It worth noting that Infinity Ward has been “monitoring anyone who uses it [the exploit] and banning them,” according to Bowling.
Subject: Robert Bowling came through! Modern Warfare 3 Proficiency Exploit Update Now Live 
Sat Jan 21, 2012 9:31 am