CVE intelligence and bounded remediation

CVE-2024-20493 — Cisco Firepower Threat Defense Software security vulnerability

Medium CVSS 5.3

A vulnerability in the login authentication functionality of the Remote Access SSL VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to deny further VPN user authentications for several minutes, resulting in a temporary denial of service (DoS) condition. This vulnerability is due to ineffective handling of memory resources during the authentication process. An attacker could exploit this vulnerability by sending crafted packets, which could cause resource exhaustion of the authentication process. A successful exploit could allow the attacker to deny authentication for Remote Access SSL VPN users for several minutes, resulting in a temporary DoS condition.

Severity
Medium
CVSS
5.3 (3.1)
Published
2024-10-23
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-772

Affected products

  • cisco / firepower_threat_defense_software / 6.2.3
  • cisco / firepower_threat_defense_software / 6.2.3.1
  • cisco / firepower_threat_defense_software / 6.2.3.2
  • cisco / firepower_threat_defense_software / 6.2.3.3
  • cisco / firepower_threat_defense_software / 6.2.3.4
  • cisco / firepower_threat_defense_software / 6.2.3.5

Showing 6 representative product identities from 294 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Resource exhaustion and denial of service

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Identify attacker-influenced work factors including input size, nesting, compression, fan-out, regex cost, allocation, recursion, retries, and connection lifetime.
  • Map per-request and shared CPU, memory, disk, descriptor, thread, queue, and downstream-service limits.
  • Determine whether authentication, tenancy, quotas, and rate controls apply before expensive processing begins.

Remediate safely

  • Bound input size, nesting, expansion, work, concurrency, queue depth, retries, and execution time before resource-intensive processing.
  • Release resources on every success, error, cancellation, and timeout path and use backpressure instead of unbounded buffering.
  • Update affected components and add small deterministic tests that assert resource ceilings rather than exhausting a host.

Authoritative sources

Complete CVE record and remediation plan

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