In a statement published Jan. 22, SonicWall officials wrote they detected an attack "by highly sophisticated threat actors exploiting probably zero-day vulnerabilities on certain SonicWall secure remote access products."
As of Jan. 23, the company has confirmed its SonicWall Firewalls, NetExtender VPN Client, Secure Mobile Access (SMA) 1000 Series, and SonicWave Access Points were not affected in the recent attack. The SMA 100 Series, used to provide employees with remote access to internal resources, is under investigation but "may be used safely in common deployment use cases."
Current SMA 100 series users may continue to use NetExtender for remote access, a use case the company has determined is not susceptible to exploitation. Admins for the SMA 100 series are advised to create specific access rules while investigation of the vulnerability is underway. SonicWall suggests using a firewall to allow only SSL-VPN connections to the SMA from known IP addresses, or to configure whitelist access on the SMA itself. The company also urges implementing multifactor authentication on all SonicWall SMA, Firewall, and MySonicWall accounts.