Wikipedia
Sality is the classification for a family of malicious software ( malware), which infects files on Microsoft Windows systems. Sality was first discovered in 2003 and has advanced over the years to become a dynamic, enduring and full-featured form of malicious code. Systems infected with Sality may communicate over a peer-to-peer (P2P) network for the purpose of relaying spam, proxying of communications, exfiltrating sensitive data, compromising web servers and/or coordinating distributed computing tasks for the purpose of processing intensive tasks (e.g. password cracking). Since 2010, certain variants of Sality have also incorporated the use of rootkit functions as part of an ongoing evolution of the malware family. Because of its continued development and capabilities, Sality is considered to be one of the most complex and formidable forms of malware to date.