Vulnerability Description
An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. By sending a signal to the CLI process, undocumented functionality is triggered. Specifically, a menu can be triggered by sending the SIGQUIT signal to the CLI application (e.g., through CTRL+\ via SSH). The access control check for this menu does work and prohibits accessing the menu, which contains "Password recovery for specific user" options. The menu is believed to be accessible using a serial console.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Zyxel | Gs1900-8 Firmware | < 2.50\(aahh.0\)c0 |
| Zyxel | Gs1900-8 | - |
| Zyxel | Gs1900-8Hp Firmware | < 2.50\(aahi.0\)c0 |
| Zyxel | Gs1900-8Hp | - |
| Zyxel | Gs1900-10Hp Firmware | < 2.50\(aazi.0\)c0 |
| Zyxel | Gs1900-10Hp | - |
| Zyxel | Gs1900-16 Firmware | < 2.50\(aahj.0\)c0 |
| Zyxel | Gs1900-16 | - |
| Zyxel | Gs1900-24E Firmware | < 2.50\(aahk.0\)c0 |
| Zyxel | Gs1900-24E | - |
| Zyxel | Gs1900-24 Firmware | < 2.50\(aahl.0\)c0 |
| Zyxel | Gs1900-24 | - |
| Zyxel | Gs1900-24Hp Firmware | < 2.50\(aahm.0\)c0 |
| Zyxel | Gs1900-24Hp | - |
| Zyxel | Gs1900-48 Firmware | < 2.50\(aahn.0\)c0 |
| Zyxel | Gs1900-48 | - |
| Zyxel | Gs1900-48Hp Firmware | < 2.50\(aaho.0\)c0 |
| Zyxel | Gs1900-48Hp | - |
References
- https://jasper.la/exploring-zyxel-gs1900-firmware-with-ghidra.htmlExploitThird Party Advisory
- https://www.zyxel.com/support/gs1900-switch-vulnerabilities.shtmlVendor Advisory
- https://jasper.la/exploring-zyxel-gs1900-firmware-with-ghidra.htmlExploitThird Party Advisory
- https://www.zyxel.com/support/gs1900-switch-vulnerabilities.shtmlVendor Advisory
FAQ
What is CVE-2019-15804?
CVE-2019-15804 is a vulnerability with a CVSS score of 7.5 (HIGH). An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. By sending a signal to the CLI process, undocumented functionality is triggered. Specifically, a menu can be trigge...
How severe is CVE-2019-15804?
CVE-2019-15804 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2019-15804?
Check the references section above for vendor advisories and patch information. Affected products include: Zyxel Gs1900-8 Firmware, Zyxel Gs1900-8, Zyxel Gs1900-8Hp Firmware, Zyxel Gs1900-8Hp, Zyxel Gs1900-10Hp Firmware.