CVE intelligence and bounded remediation

CVE-2020-1667 — Juniper Junos security vulnerability

High CVSS 8.3

When DNS filtering is enabled on Juniper Networks Junos MX Series with one of the following cards MS-PIC, MS-MIC or MS-MPC, an incoming stream of packets processed by the Multiservices PIC Management Daemon (mspmand) process might be bypassed due to a race condition. Due to this vulnerability, mspmand process, responsible for managing "URL Filtering service", can crash, causing the Services PIC to restart. While the Services PIC is restarting, all PIC services including DNS filtering service (DNS sink holing) will be bypassed until the Services PIC completes its boot process. This issue affects Juniper Networks Junos OS: 17.3 versions prior to 17.3R3-S8; 18.3 versions prior to 18.3R3-S1; 18.4 versions prior to 18.4R3; 19.1 versions prior to 19.1R3; 19.2 versions prior to 19.2R2; 19.3 versions prior to 19.3R3. This issue does not affect Juniper Networks Junos OS 17.4, 18.1, and 18.2.

Severity
High
CVSS
8.3 (3.1)
Published
2020-10-16
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-362

Affected products

  • juniper / junos / 17.3

Showing 1 representative product identities from 56 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Race condition, TOCTOU, and lifecycle synchronization

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Check exposure

  • Map concurrent actors, shared state, lock boundaries, signals, callbacks, retries, and check-then-use sequences in the affected path.
  • Determine whether untrusted users can influence timing, object names, filesystem state, or repeated state transitions.
  • Identify clustered and multi-process behavior that repository-local tests may not represent.

Remediate safely

  • Make the sensitive state transition atomic or protect it with a consistently ordered synchronization primitive.
  • Perform authorization and invariant checks on the same authoritative object and transaction used for the operation.
  • Use unique private resources, safe ownership transfer, and idempotent operations; add deterministic concurrency regression tests.

Authoritative sources

Complete CVE record and remediation plan

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