Sel 451 FirmwareOperating system · Selinc

CVE-2023-34388

CRITICAL · 9.8 CVSS v3.1 Published 2023-11-30
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
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
An Improper Authentication vulnerability in the Schweitzer Engineering Laboratories SEL-451 could allow a remote unauthenticated attacker to potentially perform session hijacking attack and bypass authentication. See product Instruction Manual Appendix A dated 20230830 for more details.

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 · moderate confidence

The SEL-451 protection relay contains an improper authentication vulnerability that allows a remote unauthenticated attacker to bypass authentication mechanisms and potentially perform session hijacking. This critical flaw in the authentication logic could allow an attacker to gain unauthorized access to the device and potentially modify protection settings or disrupt grid operations.

MitigationApply the firmware update referenced in SEL Instruction Manual Appendix A (20230830) and restrict network access to the SEL-451 by placing it behind a firewall or in a dedicated industrial DMZ.

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
Sel 451 FirmwareOperating system
Affected:>= r315-v0, < r315-v4>= r316-v0, < r316-v4>= r317-v0, < r317-v4>= r318-v0, < r318-v5>= r320-v0, < r320-v3>= r321-v0, < r321-v3>= r322-v0, < r322-v3>= r323-v0, < r323-v5>= r324-v0, < r324-v4>= r325-v0, < r325-v3= r326-v0= r327-v0

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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. Check the SEL-451 firmware version
    Access the SEL-451 web interface and navigate to the Device Information or Status page, or use the SEL AcSELerator software to query the device for its firmware version string (for example, display the firmware version shown as rXXX-vY)
    Affected if The displayed firmware version falls within any of these ranges: r315-v0 to r315-v3, r316-v0 to r316-v3, r317-v0 to r317-v3, r318-v0 to r318-v4, r320-v0 to r320-v2, r321-v0 to r321-v2, r322-v0 to r322-v2, r323-v0 to r323-v4, r324-v0 to r324-v3, r325-v0 to r325-v2, or is exactly r326-v0 or r327-v0
  2. Verify network accessibility of the device
    Determine if the SEL-451 management interface (web server or telnet) is reachable from untrusted networks by reviewing firewall rules, performing a port scan from an external location, or checking network segmentation configurations
    Affected if The SEL-451 is directly accessible from the internet, a corporate network, or any network segment that contains untrusted devices without being protected by a firewall or DMZ
  3. Confirm authentication interface is exposed
    Check if the SEL-451 HTTP/HTTPS management port (typically port 80/443) or telnet port is open and responding by attempting a connection from a non-trusted network segment
    Affected if The authentication web portal or login prompt is reachable from an untrusted network without VPN or firewall filtering

The device is affected if the installed firmware version is within any of the listed affected version ranges AND the device management interface is accessible from an untrusted network segment.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the firmware update referenced in SEL Instruction Manual Appendix A (20230830) and restrict network access to the SEL-451 by placing it behind a firewall or in a dedicated industrial DMZ.

Recommended fix High confidence

Upgrade to r315-v4 or later, r316-v4 or later, r317-v4 or later, or r318-v5 or later (preferably r318-v5 as the latest fixed release)

  1. Identify the current firmware version of the SEL-451 device by accessing the device interface or checking the system information
  2. Navigate to the SEL (Schweitzer Engineering Laboratories) official support website at selinc.com
  3. Locate the SEL-451 firmware download section and obtain the appropriate fixed firmware version for your current branch
  4. Download the firmware file (e.g., r315-v4, r316-v4, r317-v4, or r318-v5 depending on your current version branch)
  5. Follow the SEL-451 firmware upgrade procedure documented in the product instruction manual
  6. Apply the firmware upgrade to the SEL-451 device
  7. After upgrade, verify the device is running the fixed firmware version and confirm normal operation
Caveat Industrial control system firmware upgrades may require downtime and should be tested in a non-production environment first; verify compatibility with connected systems before deploying

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

Fix this in Sel 451 Firmware Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing12.0 h
  • Review / QA8.0 h
44.0 hours of engineering $7,720
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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-2023-34388 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data