Cisco has raised a critical alarm concerning the exploitation of VPN services through password spraying attacks, highlighting the severity of this threat. Password spraying is an attack technique favored by hackers due to its low-risk and high-reward nature, enabling them to gain unauthorized access to multiple accounts or systems with minimal difficulty. The recent warning by Cisco emphasizes the active targeting of VPN services by such attacks, with specific reports of password spraying incidents targeting remote access VPN (RAVPN) services, including both Cisco’s products and third-party VPN concentrators.
The impact of these attacks can lead to account lockouts and create conditions resembling a Denial of Service (DoS), particularly depending on the specific environment. Although the activity appears to be linked to reconnaissance efforts, the significant risk lies in compromising VPN services, which provide remote access to internal networks, making them attractive targets for unauthorized entry.
Successful compromise of VPN services through password spraying attacks can result in unauthorized access to sensitive organizational data and systems. Threat actors can further leverage compromised VPN accounts for lateral movement and escalation of privileges within the breached environment, posing significant risks to an organization’s cybersecurity posture.
In response to these threats, cybersecurity analysts at Cisco have put forward several recommendations to mitigate the risks associated with these attacks. This includes enabling logging, securing default remote access VPN profiles, leveraging TCP shun, configuring control-plane ACL, and using certificate-based authentication for RAVPN.
