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JunosOperating system · Juniper

CVE-2020-1673

HIGH · 8.8 CVSS v3.1 Published 2020-10-16
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges

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
Insufficient Cross-Site Scripting (XSS) protection in Juniper Networks J-Web and web based (HTTP/HTTPS) services allows an unauthenticated attacker to hijack the target user's HTTP/HTTPS session and perform administrative actions on the Junos device as the targeted user. This issue only affects Juniper Networks Junos OS devices with HTTP/HTTPS services enabled such as J-Web, Web Authentication, Dynamic-VPN (DVPN), Firewall Authentication Pass-Through with Web-Redirect, and Zero Touch Provisioning (ZTP). Junos OS devices with HTTP/HTTPS services disabled are not affected. If HTTP/HTTPS services are enabled, the following command will show the httpd processes: user@device> show system processes | match http 5260 - S 0:00.13 /usr/sbin/httpd-gk -N 5797 - I 0:00.10 /usr/sbin/httpd --config /jail/var/etc/httpd.conf In order to successfully exploit this vulnerability, the attacker needs to convince the device administrator to take action such as clicking the crafted URL sent via phishing email or convince the administrator to input data in the browser console. This issue affects Juniper Networks Junos OS: 18.1 versions prior to 18.1R3-S1; 18.2 versions prior to 18.2R3-S5; 18.3 versions prior to 18.3R2-S4, 18.3R3-S2; 18.4 versions prior to 18.4R2-S5, 18.4R3-S2; 19.1 versions prior to 19.1R2-S2, 19.1R3-S1; 19.2 versions prior to 19.2R1-S5, 19.2R2; 19.3 versions prior to 19.3R2-S4, 19.3R3; 19.4 versions prior to 19.4R1-S3, 19.4R2; 20.1 versions prior to 20.1R1-S2, 20.1R2. This issue does not affect Juniper Networks Junos OS prior to 18.1R1.

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

Cross-Site Scripting (XSS) vulnerability in Juniper Networks J-Web and HTTP/HTTPS web services allows unauthenticated attackers to hijack administrative sessions by tricking users into clicking crafted URLs or entering malicious data in the browser console. This affects J-Web, Web Authentication, DVPN, Firewall Authentication Pass-Through with Web-Redirect, and ZTP services.

MitigationUpgrade Junos OS to a patched version (18.1R3-S1, 18.2R3-S5, 18.3R2-S4/18.3R3-S2, 18.4R2-S5/18.4R3-S2, 19.1R2-S2/19.1R3-S1, 19.2R1-S5/19.2R2, 19.3R2-S4/19.3R3, 19.4R1-S3/19.4R2, 20.1R1-S2/20.1R2 or later). Alternatively, disable HTTP/HTTPS services if not required.

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:= 18.1= 18.2= 18.3= 18.4= 19.1= 19.2= 19.3= 19.4= 20.1

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
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

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. Identify Junos version
    Run 'show version' on the device CLI to obtain the installed Junos OS version
    Affected if Version is 18.1, 18.2, 18.3, 18.4, 19.1, 19.2, 19.3, 19.4, or 20.1 series (compare against the affected ranges provided)
  2. Check if HTTP service is enabled
    Run 'show configuration system services' to view web service configuration
    Affected if HTTP or HTTPS service is enabled under system services
  3. Verify J-Web interface status
    Attempt to access the J-Web interface via browser or check configuration for J-Web related settings
    Affected if J-Web interface is accessible or configured on the device
  4. Check for affected authentication services
    Review configuration for Web Authentication, DVPN, Firewall Authentication Pass-Through with Web-Redirect, or ZTP services
    Affected if Any of these services are enabled and accessible via web interface

A user is affected if the device runs a vulnerable Junos version listed in the affected ranges AND has HTTP/HTTPS web services (including J-Web or the listed authentication services) enabled.

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 (18.1R3-S1, 18.2R3-S5, 18.3R2-S4/18.3R3-S2, 18.4R2-S5/18.4R3-S2, 19.1R2-S2/19.1R3-S1, 19.2R1-S5/19.2R2, 19.3R2-S4/19.3R3, 19.4R1-S3/19.4R2, 20.1R1-S2/20.1R2 or later). Alternatively, disable HTTP/HTTPS services if not required.

Fix this in Junos Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2020-1673 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data