Malware
Malware (a portmanteau for malicious software) is any software intentionally designed to cause damage to a computer, server, client, or computer network. Malware does the damage after it is implanted or introduced in some way into a target's computer and can take the form of executable code, scripts, active content, and other software. The code is described as computer viruses, worms, Trojan horses, ransomware, spyware, adware, and scareware, among other terms. Malware has a malicious intent, acting against the interest of the computer user—and so does not include software that causes unintentional harm due to some deficiency, which is typically described as a software bug.
Sality
Sality’s downloader mechanism downloads and executes additional malware as listed in the URLs received using the peer-to-peer component. The distributed malware may share the same “code signature” as the Sality payload, which may provide attribution to one group and/or that they share a large portion of the code. The additional malware typically communicates with and reports to central command and control (C&C) servers located throughout the world. According to Symantec, the "combination of file infection mechanism and the fully decentralized peer-to-peer network [...] make Sality one of the most effective and resilient malware in today's threat landscape."