dbcve.org
WeosOperating system · Westermo

CVE-2015-7923

CRITICAL · 9.0 CVSS v3.0 Published 2016-01-30
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
99/100
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
Westermo WeOS before 4.19.0 uses the same SSL private key across different customers' installations, which makes it easier for man-in-the-middle attackers to defeat cryptographic protection mechanisms by leveraging knowledge of a key.

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

Westermo WeOS devices before version 4.19.0 ship with a hardcoded, identical SSL private key embedded in the firmware across all customer installations. This means the same cryptographic key used to secure SSL/TLS connections is present on every device regardless of customer or deployment. An attacker who obtains this key (through physical access, supply chain compromise, or key extraction from one device) can decrypt all SSL/TLS traffic to any affected WeOS device, perform man-in-the-middle attacks, and impersonate the device.

MitigationUpgrade to WeOS 4.19.0 or later which should include unique per-device SSL keys. If upgrade is unavailable, implement network segmentation and VPN tunnels to add additional cryptographic layers, and contact Westermo for specific remediation guidance.

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
WeosOperating system
Affected:= 4.18.0

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
High
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/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 Westermo WeOS device
    Check the device model and firmware by logging into the device management interface or checking the device label/documentation for 'Westermo' and 'WeOS' branding
    Affected if The device is not a Westermo WeOS device (not affected)
  2. Check WeOS firmware version
    Access the device's web interface or CLI and locate the firmware version information, typically found in System > Status or through the 'show version' command
    Affected if The firmware version is 4.18.0 exactly - this is the affected version listed in the CVE
  3. Compare SSL certificate with other WeOS devices
    If you have multiple Westermo WeOS devices, extract the SSL certificate from each using openssl s_client -connect DEVICE_IP:443 or from the device's certificate store, then compare the certificate fingerprint or modulus
    Affected if Different WeOS devices show identical SSL certificate fingerprints or moduli, indicating they share the same hardcoded private key
  4. Verify SSL/TLS configuration
    Check the device's SSL/TLS settings through the management interface to confirm SSL is enabled for remote management or API access
    Affected if SSL/TLS is enabled and used for device management (the hardcoded key can be exploited)

You are affected if your Westermo WeOS device runs firmware version 4.18.0 or if multiple devices share identical SSL certificates, meaning they use the same hardcoded private key.

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

Upgrade to WeOS 4.19.0 or later which should include unique per-device SSL keys. If upgrade is unavailable, implement network segmentation and VPN tunnels to add additional cryptographic layers, and contact Westermo for specific remediation guidance.

Recommended fix High confidence

WeOS 4.19.0 or later

  1. 1. Back up the current WeOS 4.18.0 configuration to ensure settings are preserved
  2. 2. Obtain WeOS version 4.19.0 or later from the official Westermo vendor source
  3. 3. Upload and apply the WeOS 4.19.0 (or later) firmware upgrade to the affected device
  4. 4. After reboot, verify the device is running version 4.19.0 or later
  5. 5. Restore the configuration backup if needed and verify normal operation
Caveat Standard firmware upgrade risks apply - review release notes for any configuration or compatibility changes before upgrading

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

Fix this in Weos Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,980
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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-2015-7923 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