NAS (network-attached storage) maker Synology has informed customers in a security advisory on August 4th that the StealthWorker botnet is targeting NAS devices in brute-force attacks that lead to ransomware infections.
NAS devices compromised in these attacks are used to try and guess common administrative credentials to install a malicious payload, which may include ransomware. These compromised devices may then later be used to breach other Linux based devices, including Synology NAS.
Synology PSIRT (Product Security Incident Response Team) is working with CERT organizations to shut down known command and control (C2) servers behind the malware and notify potentially affected customers.