ZyXEL NAS up to 5.20 weblogin.cgi username os command injection

EntryeditHistoryDiffjsonxmlCTI
CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
8.2$0-$5k0.00

A vulnerability, which was classified as critical, was found in ZyXEL NAS up to 5.20. This affects an unknown functionality of the file weblogin.cgi. The manipulation of the argument username as part of a GET Request leads to a privilege escalation vulnerability. CWE is classifying the issue as CWE-78. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

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

The weakness was shared 03/04/2020 as confirmed advisory (CERT.org). It is possible to read the advisory at kb.cert.org. This vulnerability is uniquely identified as CVE-2020-9054 since 02/18/2020. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 5.21 eliminates this vulnerability.

Productinfoedit

Vendor

Name

CPE 2.3infoedit

CPE 2.2infoedit

CVSSv3infoedit

VulDB Meta Base Score: 8.5
VulDB Meta Temp Score: 8.2

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 9.8
NVD Vector: 🔍

CVSSv2infoedit

AVACAuCIA
🔍🔍🔍🔍🔍🔍
🔍🔍🔍🔍🔍🔍
🔍🔍🔍🔍🔍🔍
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
unlockunlockunlockunlockunlockunlock
unlockunlockunlockunlockunlockunlock
unlockunlockunlockunlockunlockunlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfoedit

Class: Privilege escalation
CWE: CWE-78
ATT&CK: Unknown

Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Dayunlockunlockunlockunlock
Todayunlockunlockunlockunlock

Threat Intelligenceinfoedit

Threat: 🔍
Adversaries: 🔍
Geopolitics: 🔍
Economy: 🔍
Predictions: 🔍
Remediation: 🔍

Countermeasuresinfoedit

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: NAS 5.21

Timelineinfoedit

02/18/2020 🔍
03/04/2020 +15 days 🔍
03/05/2020 +1 days 🔍
03/05/2020 +0 days 🔍

Sourcesinfoedit

Vendor: https://www.zyxel.com/

Advisory: kb.cert.org
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2020-9054 (🔍)

Entryinfoedit

Created: 03/05/2020 08:29 AM
Updated: 03/05/2020 08:34 AM
Changes: (17) vulnerability_cwe vulnerability_cvss2_nvd_av vulnerability_cvss2_nvd_ac vulnerability_cvss2_nvd_au vulnerability_cvss2_nvd_ci vulnerability_cvss2_nvd_ii vulnerability_cvss2_nvd_ai vulnerability_cvss3_nvd_av vulnerability_cvss3_nvd_ac vulnerability_cvss3_nvd_pr vulnerability_cvss3_nvd_ui vulnerability_cvss3_nvd_s vulnerability_cvss3_nvd_c vulnerability_cvss3_nvd_i vulnerability_cvss3_nvd_a source_cve_assigned source_cve_nvd_summary
Complete: 🔍

Comments

No comments yet. Please log in to comment.

Do you need the next level of professionalism?

Upgrade your account now!