The latest campaign to leverage Skype is a botnet circulating adware, composed entirely of Skype users. Researchers from PhishMe and Amazon Web Services helped crack down the campaign. Each time a victim downloads it an affiliate program was likely generating money for the attacker on a per-install or per-download basis. In January Skype users claimed they were seeing malicious ads that wound up leading them to sites that tricked them into downloading bogus Adobe and Java updates. Users unfamiliar with what Adobe or Java s updates usually look like were duped by the fake ads.
Source: https://threatpost.com/adware-laden-skype-botnet-disrupted/113164/