Typical Counter-Strike cheats

Wallhacks, which allow the player to see through walls. These work by altering the display driver to display objects that are normally obscured, or altering game textures to transparent ones. The only objects seen on the hackers screen are those close by. The server will not send you characters of the whole map, so you can not see across the whole map.

Speedhacks, which give the player increased speed. These work by sending false synchronization data to servers.

No recoil, which keeps the players gun shooting straight on the y axis without a kickback by removing gun physics. No spread is used to make a players gun shoot straight along the x axis.

Aimbots, which helps the player aim at enemies. These work by moving the player's view to anticipate an enemy's position.

ESP, which shows textual information about the enemy, such as, health, name, and distance, and also information about weapons lying around the map, which could be missed without the hack

Barrel hack, which shows a line that depicts where the enemy is looking

Anti-flash and anti-smoke, which remove the flashbang and smoke grenade effect. This branched off the wall hack.

Valve has implemented an anti-cheat system called Valve Anti-Cheat (VAC). Players cheating on a VAC enabled server risk having their account permanently banned from all VAC secured servers.

With the first version of VAC a ban took force almost instantly after being detected, and the cheater had to wait 2 years to have the account unbanned[citation needed]. Since VAC's second version, cheaters are not banned automatically. Rather, they are banned according to a delayed banning system, and bans are permanent. Many cheats are still not detected by VAC, and often the only effective anti-cheat solution is a human administrator watching an online game. VAC, while being effective in some ways, has also provided a boost in the purchasing of private cheats. These cheats are updated frequently, as to prevent detection, and are available to those who pay to use them or to those in the community or clan.

From Wikipedia®