CVE intelligence and bounded remediation

CVE-2018-0157 — Cisco Ios Xe security vulnerability

High CVSS 8.6

A vulnerability in the Zone-Based Firewall code of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a device to reload. The vulnerability is due to the way fragmented packets are handled in the firewall code. An attacker could exploit this vulnerability by sending fragmented IP Version 4 or IP Version 6 packets through an affected device. An exploit could allow the attacker to cause the device to crash, resulting in a denial of service (DoS) condition. The following releases of Cisco IOS XE Software are vulnerable: Everest-16.4.1, Everest-16.4.2, Everest-16.5.1, Everest-16.5.1b, Everest-16.6.1, Everest-16.6.1a. Cisco Bug IDs: CSCvf60296.

Severity
High
CVSS
8.6 (3.1)
Published
2018-03-28
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-19

Affected products

  • cisco / ios_xe / 16.4.1
  • cisco / ios_xe / 16.4.2
  • cisco / ios_xe / 16.5.1
  • cisco / ios_xe / 16.5.1b
  • cisco / ios_xe / 16.6.1
  • cisco / ios_xe / 16.6.1a

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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