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JunosOperating system · Juniper

CVE-2020-1645

HIGH · 8.3 CVSS v3.1 Published 2020-07-17
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
92/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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, responsible for managing "URL Filtering service", may 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. If the issue occurs, system core-dumps output will show a crash of mspmand process: root@device> show system core-dumps -rw-rw---- 1 nobody wheel 575685123 <Date> /var/tmp/pics/mspmand.core.<*>.gz This issue affects Juniper Networks Junos OS: 17.3 versions prior to 17.3R3-S8; 18.3 versions prior to 18.3R2-S4, 18.3R3-S1; 18.4 versions prior to 18.4R2-S5, 18.4R3; 19.1 versions prior to 19.1R2-S2, 19.1R3; 19.2 versions prior to 19.2R1-S5, 19.2R2; 19.3 versions prior to 19.3R2-S3, 19.3R3; 19.4 versions prior to 19.4R1-S3, 19.4R2. This issue does not affect Juniper Networks Junos OS releases prior to 17.3R2.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A vulnerability in the Multiservices PIC Management Daemon (mspmand) on Junos MX Series devices with MS-PIC, MS-MIC, or MS-MPC cards allows a stream of specially crafted packets to crash the mspmand process when DNS filtering is enabled, causing the Services PIC to restart and temporarily bypass all PIC services including DNS sinkholing.

MitigationUpgrade Junos OS to a patched version (17.3R3-S8+, 18.3R2-S4+, 18.3R3-S1+, 18.4R2-S5+, 18.4R3+, 19.1R2-S2+, 19.1R3+, 19.2R1-S5+, 19.2R2+, 19.3R2-S3+, 19.3R3+, 19.4R1-S3+, 19.4R2+). Until upgraded, monitor for mspmand crashes and expect service bypass during PIC restarts.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
JunosOperating system
Affected:= 17.3= 18.3= 18.4= 19.1= 19.2= 19.3= 19.4

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Confirm Junos MX Series hardware with multiservices PIC
    Run 'show chassis hardware' or 'show chassis fpc' to verify the device is an MX Series with an MS-PIC, MS-MIC, or MS-MPC card installed
    Affected if The device is an MX Series with one of these multiservices cards present
  2. Verify DNS filtering is enabled
    Run 'show configuration | match dns-filter' or inspect the configuration under 'services dns-filter' hierarchy
    Affected if DNS filtering configuration exists and is active under the multiservices PIC settings
  3. Check installed Junos version
    Run 'show version' and note the Junos OS release version (e.g., 18.4R3-S2)
    Affected if The base version matches 17.3, 18.3, 18.4, 19.1, 19.2, 19.3, or 19.4 (any R variant within these branches before the fixed releases)
  4. Inspect for mspmand crash events
    Run 'show log messages' or 'show system processes' and search for 'mspmand' crash entries or PIC restart messages
    Affected if Recent mspmand process crashes or PIC restarts are logged, especially after traffic processing

You are affected if you have an MX Series with MS-PIC/MS-MIC/MS-MPC, DNS filtering is enabled, and the Junos version is within the 17.3, 18.3-18.4, or 19.x branches before the patched releases.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Junos OS to a patched version (17.3R3-S8+, 18.3R2-S4+, 18.3R3-S1+, 18.4R2-S5+, 18.4R3+, 19.1R2-S2+, 19.1R3+, 19.2R1-S5+, 19.2R2+, 19.3R2-S3+, 19.3R3+, 19.4R1-S3+, 19.4R2+). Until upgraded, monitor for mspmand crashes and expect service bypass during PIC restarts.

Fix this in Junos Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-1645 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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