9.1
CRITICAL
CVE-2019-15803
Zyxel GS1900 Unauthenticated Debug Access Control Bypass
Description

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.

INFO

Published Date :

Nov. 14, 2019, 9:15 p.m.

Last Modified :

Nov. 21, 2024, 4:29 a.m.

Remotely Exploitable :

Yes !

Impact Score :

5.2

Exploitability Score :

3.9
Affected Products

The following products are affected by CVE-2019-15803 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Zyxel gs1900-8_firmware
2 Zyxel gs1900-24_firmware
3 Zyxel gs1900-8hp_firmware
4 Zyxel gs1900-10hp_firmware
5 Zyxel gs1900-16_firmware
6 Zyxel gs1900-24e_firmware
7 Zyxel gs1900-24hp_firmware
8 Zyxel gs1900-48_firmware
9 Zyxel gs1900-48hp_firmware
10 Zyxel gs1900-48
11 Zyxel gs1900-24e
12 Zyxel gs1900-24
13 Zyxel gs1900-16
14 Zyxel gs1900-10hp
15 Zyxel gs1900-8hp
16 Zyxel gs1900-8
17 Zyxel gs1900-24hp
18 Zyxel gs1900-48hp
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2019-15803.

URL Resource
https://jasper.la/exploring-zyxel-gs1900-firmware-with-ghidra.html Exploit Third Party Advisory
https://www.zyxel.com/support/gs1900-switch-vulnerabilities.shtml Vendor Advisory
https://jasper.la/exploring-zyxel-gs1900-firmware-with-ghidra.html Exploit Third Party Advisory
https://www.zyxel.com/support/gs1900-switch-vulnerabilities.shtml Vendor Advisory

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2019-15803 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2019-15803 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://jasper.la/exploring-zyxel-gs1900-firmware-with-ghidra.html
    Added Reference https://www.zyxel.com/support/gs1900-switch-vulnerabilities.shtml
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CWE Remap by [email protected]

    Aug. 24, 2020

    Action Type Old Value New Value
    Changed CWE CWE-20 CWE-287
  • Initial Analysis by [email protected]

    Nov. 21, 2019

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:P/I:P/A:N)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
    Changed Reference Type https://jasper.la/exploring-zyxel-gs1900-firmware-with-ghidra.html No Types Assigned https://jasper.la/exploring-zyxel-gs1900-firmware-with-ghidra.html Exploit, Third Party Advisory
    Changed Reference Type https://www.zyxel.com/support/gs1900-switch-vulnerabilities.shtml No Types Assigned https://www.zyxel.com/support/gs1900-switch-vulnerabilities.shtml Vendor Advisory
    Added CWE NIST CWE-20
    Added CPE Configuration AND OR *cpe:2.3:o:zyxel:gs1900-8_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 2.50\(aahh.0\)c0 OR cpe:2.3:h:zyxel:gs1900-8:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:zyxel:gs1900-8hp_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 2.50\(aahi.0\)c0 OR cpe:2.3:h:zyxel:gs1900-8hp:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:zyxel:gs1900-10hp_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 2.50\(aazi.0\)c0 OR cpe:2.3:h:zyxel:gs1900-10hp:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:zyxel:gs1900-16_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 2.50\(aahj.0\)c0 OR cpe:2.3:h:zyxel:gs1900-16:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:zyxel:gs1900-24e_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 2.50\(aahk.0\)c0 OR cpe:2.3:h:zyxel:gs1900-24e:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:zyxel:gs1900-24_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 2.50\(aahl.0\)c0 OR cpe:2.3:h:zyxel:gs1900-24:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:zyxel:gs1900-24hp_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 2.50\(aahm.0\)c0 OR cpe:2.3:h:zyxel:gs1900-24hp:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:zyxel:gs1900-48_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 2.50\(aahn.0\)c0 OR cpe:2.3:h:zyxel:gs1900-48:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:zyxel:gs1900-48hp_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 2.50\(aaho.0\)c0 OR cpe:2.3:h:zyxel:gs1900-48hp:-:*:*:*:*:*:*:*
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2019-15803 is associated with the following CWEs:

Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.86 }} -0.28%

score

0.82086

percentile

CVSS31 - Vulnerability Scoring System
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability