CVE-2019-15803: An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. Through an undocumented sequence of keypresses, undocumented functionality…

PriorityP359critical9.1CVSS 3.1

AVNACLPRNUINSUCHIHAN

EPSS

1.32%

67.9th percentile

An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. Through an undocumented sequence of keypresses, undocumented functionality is triggered. A diagnostics shell is triggered via CTRL-ALT-t, which prompts for the password returned by fds_sys_passDebugPasswd_ret(). The firmware contains access control checks that determine if remote users are allowed to access this functionality. The function that performs this check (fds_sys_remoteDebugEnable_ret in libfds.so) always return TRUE with no actual checks performed. The diagnostics menu allows for reading/writing arbitrary registers and various other configuration parameters which are believed to be related to the network interface chips.

Affected

9 ranges

Vendor	Product	Version range	Fixed in
zyxel	gs1900-10hp_firmware	< 2.50\(aazi.0\)c0	2.50\(aazi.0\)c0
zyxel	gs1900-16_firmware	< 2.50\(aahj.0\)c0	2.50\(aahj.0\)c0
zyxel	gs1900-24_firmware	< 2.50\(aahl.0\)c0	2.50\(aahl.0\)c0
zyxel	gs1900-24e_firmware	< 2.50\(aahk.0\)c0	2.50\(aahk.0\)c0
zyxel	gs1900-24hp_firmware	< 2.50\(aahm.0\)c0	2.50\(aahm.0\)c0
zyxel	gs1900-48_firmware	< 2.50\(aahn.0\)c0	2.50\(aahn.0\)c0
zyxel	gs1900-48hp_firmware	< 2.50\(aaho.0\)c0	2.50\(aaho.0\)c0
zyxel	gs1900-8_firmware	< 2.50\(aahh.0\)c0	2.50\(aahh.0\)c0
zyxel	gs1900-8hp_firmware	< 2.50\(aahi.0\)c0	2.50\(aahi.0\)c0

CVSS provenance

nvdv3.19.1CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

nvdv2.06.4MEDIUMAV:N/AC:L/Au:N/C:P/I:P/A:N

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