CVE intelligence and bounded remediation

CVE-2017-3793 — Cisco Adaptive Security Appliance Software security vulnerability

Medium CVSS 4.3

A vulnerability in the TCP normalizer of Cisco Adaptive Security Appliance (ASA) Software (8.0 through 8.7 and 9.0 through 9.6) and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause Cisco ASA and FTD to drop any further incoming traffic on all interfaces, resulting in a denial of service (DoS) condition. The vulnerability is due to improper limitation of the global out-of-order TCP queue for specific block sizes. An attacker could exploit this vulnerability by sending a large number of unique permitted TCP connections with out-of-order segments. An exploit could allow the attacker to exhaust available blocks in the global out-of-order TCP queue, causing the dropping of any further incoming traffic on all interfaces and resulting in a DoS condition. Cisco Bug IDs: CSCvb46321.

Severity
Medium
CVSS
4.3 (2.0)
Published
2017-04-20
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-399, CWE-400

Affected products

  • cisco / adaptive_security_appliance_software / 8.0.1.2
  • cisco / adaptive_security_appliance_software / 8.0.2
  • cisco / adaptive_security_appliance_software / 8.0.2.11
  • cisco / adaptive_security_appliance_software / 8.0.2.15
  • cisco / adaptive_security_appliance_software / 8.0.3
  • cisco / adaptive_security_appliance_software / 8.0.3.6

Showing 6 representative product identities from 253 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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