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CVE-2020-9054 : Detail

CVE-2020-9054

9.8
/
CRITICAL
OS Command Injection
A03-Injection
96.77%V3
Network
2020-02-19 23:00 +00:00
2020-03-04 18:30 +00:00
CVE.org
NVD

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Descriptions

ZyXEL NAS products running firmware version 5.21 and earlier are vulnerable to pre-authentication command injection in weblogin.cgi

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

Solutions

ZyXEL 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.

Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

Metrics

Metric Score Severity CVSS Vector Source
V3.1 9.8 CRITICAL CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Base: Exploitabilty Metrics

The Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component.

Attack Vector

This metric reflects the context by which vulnerability exploitation is possible.

Network

The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).

Attack Complexity

This metric describes the conditions beyond the attacker’s control that must exist in order to exploit the vulnerability.

Low

Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success when attacking the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

None

The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.

User Interaction

This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable component.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

The Scope metric captures whether a vulnerability in one vulnerable component impacts resources in components beyond its security scope.

Scope

Formally, a security authority is a mechanism (e.g., an application, an operating system, firmware, a sandbox environment) that defines and enforces access control in terms of how certain subjects/actors (e.g., human users, processes) can access certain restricted objects/resources (e.g., files, CPU, memory) in a controlled manner. All the subjects and objects under the jurisdiction of a single security authority are considered to be under one security scope. If a vulnerability in a vulnerable component can affect a component which is in a different security scope than the vulnerable component, a Scope change occurs. Intuitively, whenever the impact of a vulnerability breaches a security/trust boundary and impacts components outside the security scope in which vulnerable component resides, a Scope change occurs.

Unchanged

An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.

Base: Impact Metrics

The Impact metrics capture the effects of a successfully exploited vulnerability on the component that suffers the worst outcome that is most directly and predictably associated with the attack. Analysts should constrain impacts to a reasonable, final outcome which they are confident an attacker is able to achieve.

Confidentiality Impact

This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability.

High

There is a total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.

Integrity Impact

This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information.

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

High

There is a total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Temporal Metrics

The Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence in the description of a vulnerability.

Environmental Metrics

These metrics enable the analyst to customize the CVSS score depending on the importance of the affected IT asset to a user’s organization, measured in terms of Confidentiality, Integrity, and Availability.

 nvd@nist.gov
V2 10 AV:N/AC:L/Au:N/C:C/I:C/A:C nvd@nist.gov

CISA KEV (Known Exploited Vulnerabilities)

Vulnerability name : Zyxel Multiple NAS Devices OS Command Injection Vulnerability

Required action : Apply updates per vendor instructions.

Known To Be Used in Ransomware Campaigns : Unknown

Added : 2022-03-24 23:00 +00:00

Action is due : 2022-04-14 22:00 +00:00

Important informations

This CVE is identified as vulnerable and poses an active threat, according to the Catalog of Known Exploited Vulnerabilities (CISA KEV). The CISA has listed this vulnerability as actively exploited by cybercriminals, emphasizing the importance of taking immediate action to address this flaw. It is imperative to prioritize the update and remediation of this CVE to protect systems against potential cyberattacks.

EPSS

EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.

EPSS Score

The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.

EPSS Percentile

The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.
EPSS First.org

Products Mentioned

Configuraton 0

Zyxel>>Nas326_firmware >> Version To (excluding) 5.21\(aazf.7\)c0

Zyxel>>Nas326 >> Version -

Configuraton 0

Zyxel>>Nas520_firmware >> Version To (excluding) 5.21\(aasz.3\)c0

Zyxel>>Nas520 >> Version -

Configuraton 0

Zyxel>>Nas540_firmware >> Version To (excluding) 5.21\(aatb.4\)c0

Zyxel>>Nas540 >> Version -

Configuraton 0

Zyxel>>Nas542_firmware >> Version To (excluding) 5.21\(abag.4\)c0

Zyxel>>Nas542 >> Version -

Configuraton 0

Zyxel>>Atp100_firmware >> Version From (including) 4.35 To (excluding) 4.35\(abps.3\)c0

Zyxel>>Atp100 >> Version -

Configuraton 0

Zyxel>>Atp200_firmware >> Version From (including) 4.35 To (excluding) 4.35\(abfw.3\)c0

Zyxel>>Atp200 >> Version -

Configuraton 0

Zyxel>>Atp500_firmware >> Version From (including) 4.35 To (excluding) 4.35\(abfu.3\)c0

Zyxel>>Atp500 >> Version -

Configuraton 0

Zyxel>>Atp800_firmware >> Version From (including) 4.35 To (excluding) 4.35\(abiq.3\)c0

Zyxel>>Atp800 >> Version -

Configuraton 0

Zyxel>>Usg20-vpn_firmware >> Version From (including) 4.35 To (excluding) 4.35\(abaq.3\)c0

Zyxel>>Usg20-vpn >> Version -

Configuraton 0

Zyxel>>Usg20w-vpn_firmware >> Version From (including) 4.35 To (excluding) 4.35\(abar.3\)c0

Zyxel>>Usg20w-vpn >> Version -

Configuraton 0

Zyxel>>Usg40_firmware >> Version From (including) 4.35 To (excluding) 4.35\(aala.3\)c0

Zyxel>>Usg40 >> Version -

Configuraton 0

Zyxel>>Usg40w_firmware >> Version From (including) 4.35 To (excluding) 4.35\(aalb.3\)c0

Zyxel>>Usg40w >> Version -

Configuraton 0

Zyxel>>Usg60_firmware >> Version From (including) 4.35 To (excluding) 4.35\(aaky.3\)c0

Zyxel>>Usg60 >> Version -

Configuraton 0

Zyxel>>Usg60w_firmware >> Version From (including) 4.35 To (excluding) 4.35\(aakz.3\)c0

Zyxel>>Usg60w >> Version -

Configuraton 0

Zyxel>>Usg110_firmware >> Version From (including) 4.35 To (excluding) 4.35\(aaph.3\)c0

Zyxel>>Usg110 >> Version -

Configuraton 0

Zyxel>>Usg210_firmware >> Version From (including) 4.35 To (excluding) 4.35\(aapi.3\)c0

Zyxel>>Usg210 >> Version -

Configuraton 0

Zyxel>>Usg310_firmware >> Version From (including) 4.35 To (excluding) 4.35\(aapj.3\)c0

Zyxel>>Usg310 >> Version -

Configuraton 0

Zyxel>>Usg1100_firmware >> Version From (including) 4.35 To (excluding) 4.35\(aapk.3\)c0

Zyxel>>Usg1100 >> Version -

Configuraton 0

Zyxel>>Usg1900_firmware >> Version From (including) 4.35 To (excluding) 4.35\(aapl.3\)c0

Zyxel>>Usg1900 >> Version -

Configuraton 0

Zyxel>>Usg2200_firmware >> Version From (including) 4.35 To (excluding) 4.35\(abae.3\)c0

Zyxel>>Usg2200 >> Version -

Configuraton 0

Zyxel>>Vpn50_firmware >> Version From (including) 4.35 To (excluding) 4.35\(abhl.3\)c0

Zyxel>>Vpn50 >> Version -

Configuraton 0

Zyxel>>Vpn100_firmware >> Version From (including) 4.35 To (excluding) 4.35\(abfv.3\)c0

Zyxel>>Vpn100 >> Version -

Configuraton 0

Zyxel>>Vpn300_firmware >> Version From (including) 4.35 To (excluding) 4.35\(abfc.3\)c0

Zyxel>>Vpn300 >> Version -

Configuraton 0

Zyxel>>Vpn1000_firmware >> Version From (including) 4.35 To (excluding) 4.35\(abip.3\)c0

Zyxel>>Vpn1000 >> Version -

Configuraton 0

Zyxel>>Zywall110_firmware >> Version From (including) 4.35 To (excluding) 4.35\(aaaa.3\)c0

Zyxel>>Zywall110 >> Version -

Configuraton 0

Zyxel>>Zywall310_firmware >> Version From (including) 4.35 To (excluding) 4.35\(aaab.3\)c0

Zyxel>>Zywall310 >> Version -

Configuraton 0

Zyxel>>Zywall1100_firmware >> Version From (including) 4.35 To (excluding) 4.35\(aaac.3\)c0

Zyxel>>Zywall1100 >> Version -

References

https://kb.cert.org/vuls/id/498544/
Tags : third-party-advisory, x_refsource_CERT-VN

More information
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