CVE-2020-9054

Scores

EPSS

0.943high94.3%
0%20%40%60%80%100%

Percentile: 94.3%

CVSS

9.8critical3.x
0246810

CVSS Score: 9.8/10

All CVSS Scores

CVSS 3.x
9.8

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS 2.0
10.0

Vector: AV:N/AC:L/Au:N/C:C/I:C/A:C

Description

Multiple ZyXEL network-attached storage (NAS) devices running firmware version 5.21 contain a pre-authentication command injection vulnerability, which may allow a remote, unauthenticated attacker to execute arbitrary code on a vulnerable device. ZyXEL NAS devices achieve authentication by using the weblogin.cgi CGI executable. This program fails to properly sanitize the username parameter that is passed to it. If the username parameter contains certain characters, it can allow command injection with the privileges of the web server that runs on the ZyXEL device. Although the web server does not run as the root user, ZyXEL devices include a setuid utility that can be leveraged to run any command with root privileges. As such, it should be assumed that exploitation of this vulnerability can lead to remote code execution with root privileges. By sending a specially-crafted HTTP POST or GET request to a vulnerable ZyXEL device, a remote, unauthenticated attacker may be able to execute arbitrary code on the device. This may happen by directly connecting to a device if it is directly exposed to an attacker. However, there are ways to trigger such crafted requests even if an attacker does not have direct connectivity to a vulnerable devices. For example, simply visiting a website can result in the compromise of any ZyXEL device that is reachable from the client system. Affected products include: NAS326 before firmware V5.21(AAZF.7)C0 NAS520 before firmware V5.21(AASZ.3)C0 NAS540 before firmware V5.21(AATB.4)C0 NAS542 before firmware V5.21(ABAG.4)C0 ZyXEL has made firmware updates available for NAS326, NAS520, NAS540, and NAS542 devices. Affected models that are end-of-support: NSA210, NSA220, NSA220+, NSA221, NSA310, NSA310S, NSA320, NSA320S, NSA325 and NSA325v2

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Sources

nvd

CWEs

CWE-78

Related Vulnerabilities

Exploits

Exploit ID: CVE-2020-9054

Source: cisa

URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

Recommendations

Source: nvd

Apply an updateZyXEL has made firmware updates available for NAS326, NAS520, NAS540, NAS542, ATP100, ATP200, ATP500, ATP800, USG20-VPN, USG20W-VPN, USG40, USG40W, USG60, USG60W, USG110, USG210, USG310, USG1100, USG1900, USG2200, VPN50, VPN100, VPN300, VPN1000, ZyWALL110, ZyWALL310, and ZyWALL1100 devices. Owners of NSA210, NSA220, NSA220+, NSA221, NSA310, NSA310S, NSA320, NSA320S, NSA325 and NSA325v2 as well as some other ZyXEL devices may not be able to install firmware updates, as these devices are no longer supported. Be cautious when updating firmware on affected devices, as the ZyXEL firmware upgrade process both uses an insecure channel (FTP) for retrieving updates, and the firmware files are only verified by checksum rather than cryptographic signature. For these reasons, any attacker that has control of DNS or IP routing may be able to cause a malicious firmware to be installed on a ZyXEL device.Please also consider the following workarounds:Block access to the ZyXEL device web interfaceThis issue can be mitigated by blocking (for example with a firewall) access to the web interface (80/tcp and 443/tcp) of any vulnerable ZyXEL device. Any machine that can access the ZyXEL web interface should not also be able to access the internet.Restrict access to vulnerable ZyXEL devicesDirect exploitation of this vulnerability can be mitigated by restricting access to vulnerable devices. In particular, do not expose such devices directly to the internet. Note however, that it is still possible for attackers to exploit devices that are not directly connected to the internet. For example, by way of viewing a web page.

URL: https://kb.cert.org/vuls/id/498544/

Vulnerable Software (27)

Type: Configuration

Vendor: zyxel

Product: atp100_firmware

Operating System: * * *

Trait:
{  "children": [    {      "cpe_match": [        {          "cpe23uri": "cpe:2.3:o:zyxel:atp100_firmware:*:*:*:*:*:*:*:*",          "versionEndExcluding": "4.35\\(abps.3\\)c0",          "versio...

Source: nvd

Type: Configuration

Vendor: zyxel

Product: atp200_firmware

Operating System: * * *

Trait:
{  "children": [    {      "cpe_match": [        {          "cpe23uri": "cpe:2.3:o:zyxel:atp200_firmware:*:*:*:*:*:*:*:*",          "versionEndExcluding": "4.35\\(abfw.3\\)c0",          "versio...

Source: nvd

Type: Configuration

Vendor: zyxel

Product: atp500_firmware

Operating System: * * *

Trait:
{  "children": [    {      "cpe_match": [        {          "cpe23uri": "cpe:2.3:o:zyxel:atp500_firmware:*:*:*:*:*:*:*:*",          "versionEndExcluding": "4.35\\(abfu.3\\)c0",          "versio...

Source: nvd

Type: Configuration

Vendor: zyxel

Product: atp800_firmware

Operating System: * * *

Trait:
{  "children": [    {      "cpe_match": [        {          "cpe23uri": "cpe:2.3:o:zyxel:atp800_firmware:*:*:*:*:*:*:*:*",          "versionEndExcluding": "4.35\\(abiq.3\\)c0",          "versio...

Source: nvd

Type: Configuration

Vendor: zyxel

Product: nas326_firmware

Operating System: * * *

Trait:
{  "children": [    {      "cpe_match": [        {          "cpe23uri": "cpe:2.3:o:zyxel:nas326_firmware:*:*:*:*:*:*:*:*",          "versionEndExcluding": "5.21\\(aazf.7\\)c0",          "vulner...

Source: nvd

Type: Configuration

Vendor: zyxel

Product: nas520_firmware

Operating System: * * *

Trait:
{  "children": [    {      "cpe_match": [        {          "cpe23uri": "cpe:2.3:o:zyxel:nas520_firmware:*:*:*:*:*:*:*:*",          "versionEndExcluding": "5.21\\(aasz.3\\)c0",          "vulner...

Source: nvd

Type: Configuration

Vendor: zyxel

Product: nas540_firmware

Operating System: * * *

Trait:
{  "children": [    {      "cpe_match": [        {          "cpe23uri": "cpe:2.3:o:zyxel:nas540_firmware:*:*:*:*:*:*:*:*",          "versionEndExcluding": "5.21\\(aatb.4\\)c0",          "vulner...

Source: nvd

Type: Configuration

Vendor: zyxel

Product: nas542_firmware

Operating System: * * *

Trait:
{  "children": [    {      "cpe_match": [        {          "cpe23uri": "cpe:2.3:o:zyxel:nas542_firmware:*:*:*:*:*:*:*:*",          "versionEndExcluding": "5.21\\(abag.4\\)c0",          "vulner...

Source: nvd

Type: Configuration

Vendor: zyxel

Product: usg1100_firmware

Operating System: * * *

Trait:
{  "children": [    {      "cpe_match": [        {          "cpe23uri": "cpe:2.3:o:zyxel:usg1100_firmware:*:*:*:*:*:*:*:*",          "versionEndExcluding": "4.35\\(aapk.3\\)c0",          "versi...

Source: nvd

Type: Configuration

Vendor: zyxel

Product: usg110_firmware

Operating System: * * *

Trait:
{  "children": [    {      "cpe_match": [        {          "cpe23uri": "cpe:2.3:o:zyxel:usg110_firmware:*:*:*:*:*:*:*:*",          "versionEndExcluding": "4.35\\(aaph.3\\)c0",          "versio...

Source: nvd