The cybersecurity authorities of the United Kingdom (NCSC-UK), Australia (ACSC), Canada (CCCS), New Zealand (NCSC-NZ), and the United States (CISA), (NSA), (FBI) are aware of recent reports that observe an increase in malicious cyber activity targeting managed service providers (MSPs) and expect this trend to continue.[1] This joint Cybersecurity Advisory (CSA) provides actions MSPs and their customers can take to reduce their risk of falling victim to a cyber intrusion.