Brazilian internet users suffer SoftLayer's security fail

The article examines a summer 2015 spike in Spamhaus SBL listings that placed SoftLayer at the top of Spamhaus's problematic ISPs list, tracing the problem to a concentrated spam and malware operation that exploited SoftLayer's services; it explains how an otherwise reputable ISP became heavily abused and provides lessons for other ISPs to prevent similar large-scale spam/malware abuse.