Cisco AnyConnect VPN Server vulnerable to DoS attack

CVE-2024-20502

Summary

A vulnerability in the Cisco AnyConnect VPN server, present in Cisco Meraki MX and Cisco Meraki Z Series Teleworker Gateway devices, allows an unauthenticated remote attacker to induce a Denial of Service (DoS) condition. This issue arises from inadequate resource management during the establishment of SSL VPN sessions. By sending a series of specially crafted HTTPS requests to the VPN server, an attacker can prevent the device from accepting new VPN connections. Importantly, existing SSL VPN sessions remain unaffected when this vulnerability is exploited. Fortunately, the Cisco AnyConnect VPN server is capable of recovering gracefully once the malicious traffic ceases, eliminating the need for manual intervention.

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