Friday the security researchers at Arctic Wolf Labs wrote:In late July 2025, Arctic Wolf Labs began observing a surge of intrusions involving suspicious SonicWall SSL VPN activity. Malicious logins were followed within minutes by port scanning, Impacket SMB activity, and rapid deployment of Akira ransomware. Victims spanned across multiple sectors and organization sizes, suggesting opportunistic mass exploitation. This campaign has recently escalated, with new infrastructure linked to it observed as late as September 20, 2025. More from Cybersecurity News:SonicWall has linked these malicious logins to CVE-2024-40766, an improper access control vulnerability disclosed in 2024. The working theory is that threat actors harvested credentials from devices that were previously vulnerable and are now using them in this campaign, even if the devices have since been patched. This explains why fully patched devices have been compromised, a fact that initially led to speculation about a potential zero-day exploit. Once inside a network, the attackers operate with remarkable speed. The time from initial access to ransomware deployment, known as "dwell time," is often measured in hours, with some intrusions taking as little as 55 minutes, Arctic Wolf said. This extremely short window for response makes early detection critical. "Threat actors in the present campaign successfully authenticated against accounts with the one-time password (OTP) MFA feature enabled..." notes Artic Wolf Labs:The threats described in this campaign demand early detection and a rapid response to avoid catastrophic impact to organizations. To facilitate this process, we recommend monitoring for VPN logins originating from untrusted hosting infrastructure. Equally important is ensuring visibility into internal networks, since lateral movement and ransomware encryption can occur within hours or even minutes of initial access. Monitoring for anomalous SMB activity indicative of Impacket use provides an additional early detection opportunity. When firewalls are confirmed to be running firmware versions vulnerable to credential access or full configuration export, patching alone is not enough. In such situations, credentials must be reset wherever possible, including MFA-related secrets that might otherwise be thought of as secure, and Active Directory credentials with VPN access. These considerations are best practices that apply regardless of which firewall products are in use. Thanks to Slashdot reader Mirnotoriety for suggesting this story.Read more of this story at Slashdot.