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.
zyxel
CVE-2019-13495
In firmware version 4.50 of Zyxel XGS2210-52HP, multiple stored cross-site scripting (XSS) issues allows remote authenticated users to inject arbitrary web script via an rpSys.html Name or Location field.
CVE-2019-12583
Missing Access Control in the “Free Time” component of several Zyxel UAG, USG, and ZyWall devices allows a remote attacker to generate guest accounts by directly accessing the account generator. This can lead to unauthorised network access or Denial of Service.
CVE-2019-12581
A reflective Cross-site scripting (XSS) vulnerability in the free_time_failed.cgi CGI program in selected Zyxel ZyWall, USG, and UAG devices allows remote attackers to inject arbitrary web script or HTML via the err_msg parameter.
CVE-2019-10634
An XSS vulnerability in the Zyxel NAS 326 version 5.21 and below allows a remote authenticated attacker to inject arbitrary JavaScript or HTML via the user, group, and file-share description fields.
CVE-2019-10633
An eval injection vulnerability in the Python web server routing on the Zyxel NAS 326 version 5.21 and below allows a remote authenticated attacker to execute arbitrary code via the tjp6jp6y4, simZysh, and ck6fup6 APIs.