CVE intelligence and bounded remediation

CVE-2019-15799 — An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0

High CVSS 9

An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. User accounts created through the web interface of the device, when given non-admin level privileges, have the same level of privileged access as administrators when connecting to the device via SSH (while their permissions via the web interface are in fact restricted). This allows normal users to obtain the administrative password by running the tech-support command via the CLI: this contains the encrypted passwords for all users on the device. As these passwords are encrypted using well-known and static parameters, they can be decrypted and the original passwords (including the administrator password) can be obtained.

Severity
High
CVSS
9 (2.0)
Published
2019-11-14
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-269

Affected products

  • zyxel / gs1900-8_firmware
  • zyxel / gs1900-8hp_firmware
  • zyxel / gs1900-10hp_firmware
  • zyxel / gs1900-16_firmware
  • zyxel / gs1900-24e_firmware
  • zyxel / gs1900-24_firmware

Showing 6 representative product identities from 9 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Privilege escalation and unsafe privilege management

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Check exposure

  • Map service accounts, operating-system identities, roles, capabilities, impersonation, set-user transitions, and administrative helper paths.
  • Determine whether untrusted users or lower-privilege processes can reach the affected transition or modify inputs it trusts.
  • Review file, socket, registry, device, job, container, and cloud-role permissions used before and after privilege changes.

Remediate safely

  • Apply the supported fix and redesign privileged operations as a minimal, authenticated, allowlisted interface.
  • Drop privileges before processing untrusted input, verify the drop succeeds, and remove unnecessary roles, capabilities, and write permissions.
  • Validate ownership and permissions at time of use and add explicit lower-to-higher privilege boundary tests.

Authoritative sources

Complete CVE record and remediation plan

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