CVE-2020-13364 : Exploit Details and Defense Strategies

A backdoor in certain Zyxel products allows remote TELNET access via a CGI script. This affects various NAS models.

Understanding CVE-2020-13364

This CVE involves a backdoor vulnerability in Zyxel products that enables unauthorized remote TELNET access.

What is CVE-2020-13364?

The vulnerability allows attackers to gain remote access to affected Zyxel products using TELNET through a CGI script.

The Impact of CVE-2020-13364

CVSS Base Score: 6.5 (Medium Severity)
Attack Vector: Network
Attack Complexity: Low
Confidentiality Impact: Low
Integrity Impact: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Availability Impact: None

Technical Details of CVE-2020-13364

This section provides detailed technical information about the vulnerability.

Vulnerability Description

The vulnerability allows remote TELNET access to certain Zyxel products via a CGI script.

Affected Systems and Versions

NAS520: V5.21(AASZ.4)C0, V5.21(AASZ.0)C0, V5.11(AASZ.3)C0, V5.11(AASZ.0)C0
NAS542: V5.11(ABAG.0)C0, V5.20(ABAG.1)C0, V5.21(ABAG.3)C0
NSA325: v2_V4.81(AALS.0)C0, V4.81(AAAJ.1)C0
and more...

Exploitation Mechanism

The vulnerability can be exploited remotely by attackers to gain unauthorized access to the affected Zyxel products.

Mitigation and Prevention

Protect your systems from CVE-2020-13364 with these mitigation strategies.

Immediate Steps to Take

Disable TELNET access if not required
Implement firewall rules to restrict access
Apply vendor-supplied patches or updates

Long-Term Security Practices

Regularly update firmware and software
Conduct security assessments and audits
Monitor network traffic for suspicious activities

Patching and Updates

Check Zyxel's security advisories for patches
Apply recommended security updates promptly