CVE intelligence and bounded remediation

CVE-2018-0156 — Cisco IOS Software and Cisco IOS XE Software Smart Install Denial-of-Service Vulnerability

High CVSS 7.8 CISA KEV

A vulnerability in the Smart Install feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to improper validation of packet data. An attacker could exploit this vulnerability by sending a crafted packet to an affected device on TCP port 4786. Only Smart Install client switches are affected. Cisco devices that are configured as a Smart Install director are not affected by this vulnerability. Cisco Bug IDs: CSCvd40673.

Severity
High
CVSS
7.8 (2.0)
Published
2018-03-28
CISA KEV
Known exploited
Ecosystem
operating-system
Weaknesses
CWE-399, CWE-20

Affected products

  • cisco / ios / 15.2(2)e4
  • cisco / ios / 15.2(2a)ja
  • cisco / ios_xe / 15.2(2)e4
  • cisco / ios_xe / 15.2(2a)ja

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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