CVE intelligence and bounded remediation

CVE-2020-27121 — Cisco Unified Communications Manager Im And Presence Service security vulnerability

Medium CVSS 6.5

A vulnerability in Cisco Unified Communications Manager IM & Presence Service (Unified CM IM&P) Software could allow an authenticated, remote attacker to cause the Cisco XCP Authentication Service on an affected device to restart, resulting in a denial of service (DoS) condition. The vulnerability is due to improper handling of login requests. An attacker could exploit this vulnerability by sending a crafted client login request to an affected device. A successful exploit could allow the attacker to cause a process to crash, resulting in a DoS condition for new login attempts. Users who are authenticated at the time of the attack would not be affected. There are workarounds that address this vulnerability.

Severity
Medium
CVSS
6.5 (3.1)
Published
2020-11-06
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-248, CWE-755

Affected products

  • cisco / unified_communications_manager_im_and_presence_service / 12.5(1)

Matched remediation archetype

Resource exhaustion and denial of service

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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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