CVE-2020-9054

Zyxel Multiple Network-Attached Storage (NAS) Devices: Multiple NAS Devices OS Command Injection

As of , CVE-2020-9054 in Zyxel Multiple Network-Attached Storage (NAS) Devices is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch this week.

Exploited
Yes: CISA listed it on 25 March 2022
US federal deadline
15 April 202221 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
Not known to CISA
EPSS score
0.99Higher than 99% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
EPSS when listed
0.89 on 25 March 2022EPSS on the day CISA listed it.
Public exploit
None foundNeither Metasploit nor Exploit-DB lists one.
Fix
No vendor link in CISA's entry

What CISA says to do

Apply updates per vendor instructions.

CISA's required action

What the flaw is

Multiple Zyxel network-attached storage (NAS) devices contain a pre-authentication command injection vulnerability, which may allow a remote, unauthenticated attacker to execute arbitrary code.

CISA's 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.

The CVE record's description, from certcc, shortened; full text on cve.org

CVE published
4 March 2020
Assigned by
certcc
CVSS
9.8 Critical (CVSS 3.1, from CISA-ADP)
CWE-78
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
CISA SSVC, exploitation
active
CISA SSVC, automatable
no
CISA SSVC, technical impact
total

Timeline

  1. The CVE record was published.
  2. CISA added it to its list of exploited vulnerabilities.
  3. The US federal deadline to fix it.

Multiple Network-Attached Storage (NAS) Devices: other exploited entries

VulnerabilityProductOur groupListedDeadlineEPSS
CVE-2023-27992Multiple NAS Devices Command InjectionZyxel Multiple Network-Attached Storage (NAS) DevicesPatch this weekEPSS 0.830.83

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