Cisco Email Security Appliance (ESA) Vulnerability: High CPU Usage DoS Attack

CVE-2020-3548

Summary

A vulnerability exists within the Transport Layer Security (TLS) implementation of Cisco AsyncOS software for the Email Security Appliance (ESA). This flaw allows an unauthenticated, remote attacker to exploit how incoming TLS traffic is processed, potentially resulting in significant CPU demand on the affected device. By sending specifically crafted TLS packets, an attacker can induce a state of elevated CPU utilization, leading to service disruptions characterized by degraded response times and overall performance. The affected device remains operational but may experience significant delays, compromising the efficiency of email security operations. Current configurations lack effective mitigation strategies for this vulnerability.

References