The PokerAgent botnet was discovered in 2012 by ESET Security Research Lab. Trojan horse designed to harvest Facebook log-on credentials, also collecting credit card details linked to the Facebook account and Zynga Poker player stats. At least 800 computers have been infected with the Trojan and the attacker had at least 16194 unique entries in his database of stolen Facebook credentials by March 20, 2012. The Trojan is active with many variants and belongs to MSIL/Agent.NKY family. It is coded in C# language and easy to decompile.
Source: https://thehackernews.com/2013/01/pokeragent-botnet-stole-over-16000.html