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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 17 Nov 2023.
JunosOperating system · Juniper

CVE-2023-36847

MEDIUM · 5.3 CVSS v3.1 Published 2023-08-17
Fix available
A fix is available. Upgrade to 20.4 or later.
See remediation →
100/100
Remediation priority · Urgent
In the wild High EPSS 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
A Missing Authentication for Critical Function vulnerability in Juniper Networks Junos OS on EX Series allows an unauthenticated, network-based attacker to cause limited impact to the file system integrity. With a specific request to installAppPackage.php that doesn't require authentication an attacker is able to upload arbitrary files via J-Web, leading to a loss of integrity for a certain part of the file system, which may allow chaining to other vulnerabilities. This issue affects Juniper Networks Junos OS on EX Series: * All versions prior to 20.4R3-S8; * 21.1 versions 21.1R1 and later; * 21.2 versions prior to 21.2R3-S6; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3-S4; * 22.1 versions prior to 22.1R3-S3; * 22.2 versions prior to 22.2R3-S1; * 22.3 versions prior to 22.3R2-S2, 22.3R3; * 22.4 versions prior to 22.4R2-S1, 22.4R3.

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

This is a missing authentication vulnerability in Juniper Junos OS J-Web interface on EX Series. The installAppPackage.php script can be accessed without authentication, allowing unauthenticated network-based attackers to upload arbitrary files to a limited portion of the file system. This can lead to integrity loss and potential chaining with other vulnerabilities.

MitigationApply the appropriate Junos OS version upgrade per the vendor's specified version matrix to patch the authentication bypass in J-Web, and restrict J-Web interface access to trusted networks.

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:< 20.4= 20.4= 21.1= 21.2= 21.3= 21.4= 22.1= 22.2= 22.3= 22.4

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
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

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

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. Verify J-Web interface is enabled
    Log into the Junos device CLI and run 'show system services web-management' to check if J-Web is enabled
    Affected if J-Web web-management service is listed as enabled
  2. Identify Junos OS version
    Run 'show version' in the Junos CLI to obtain the installed OS version number
    Affected if The installed version matches one of the affected versions: any version < 20.4, or exactly 20.4, 21.1, 21.2, 21.3, 21.4, 22.1, 22.2, 22.3, or 22.4
  3. Confirm J-Web HTTP/HTTPS service is listening
    Run 'show system services web-management http' or 'show system services web-management https' to see if J-Web is listening on any interface
    Affected if J-Web HTTP or HTTPS service is actively listening and reachable
  4. Check for the vulnerable PHP endpoint
    From an external host, attempt to access the URI /installAppPackage.php on the J-Web interface (e.g., http://device-ip/installAppPackage.php)
    Affected if The endpoint responds (even with an error) indicating the script exists and J-Web is exposed

You are affected if J-Web is enabled and listening on your Junos device, and the installed Junos OS version falls within the affected version list (any version before 20.4R3-S8, 21.2R3-S6, 21.3R3-S5, 21.4R3-S4, 22.1R3-S3, 22.2R3-S1, 22.3R2-S2/22.3R3, or 22.4R2-S1/22.4R3).

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.

dbcve · scoped
Upgrade available Upgrade to 20.4 or later
Fixed in 20.4
Interim mitigation

Apply the appropriate Junos OS version upgrade per the vendor's specified version matrix to patch the authentication bypass in J-Web, and restrict J-Web interface access to trusted networks.

Recommended fix High confidence

Upgrade to 20.4R3-S8 or later for 20.4 branch; 21.2R3-S6 or later for 21.2 branch; 21.3R3-S5 or later for 21.3 branch; 21.4R3-S4 or later for 21.4 branch; 22.1R3-S3 or later for 22.1 branch; 22.2R3-S1 or later for 22.2 branch; 22.3R3 for 22.3 branch; 22.4R3 for 22.4 branch

  1. 1. Identify the current Junos OS version running on the EX Series device using 'show version'
  2. 2. Determine which version branch your current release belongs to (20.4, 21.1, 21.2, 21.3, 21.4, 22.1, 22.2, 22.3, or 22.4)
  3. 3. Plan upgrade to the first fixed version for your branch: 20.4R3-S8, 21.2R3-S6, 21.3R3-S5, 21.4R3-S4, 22.1R3-S3, 22.2R3-S1, 22.3R3, or 22.4R3 respectively
  4. 4. Download the appropriate Junos OS upgrade image from Juniper Networks support portal
  5. 5. Back up the current configuration using 'request system snapshot'
  6. 6. Upload the new image to the device and install using 'request system software add <package-name>'
  7. 7. Reboot the device after installation using 'request system reboot'
  8. 8. Verify the new version is running and functionality is intact using 'show version'
Caveat Standard Junos OS upgrade considerations apply - review release notes for known issues and ensure compatibility with EX Series hardware

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Junos Exploited in the wild — priority engagement
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,750
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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-2023-36847 in production — separate from our analysis above.

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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
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  • No spam, self-promotion, credentials, or personal data