Home/CVE/Certain Zyxel products have a locally accessible binary that allows a non-root user to generate a password for an undocu
CVE

CVE-2020-13365

Certain Zyxel products have a locally accessible binary that allows a non-root user to generate a password for an undocu

Certain Zyxel products have a locally accessible binary that allows a non-root user to generate a password for an undocumented user account that can be used for a TELNET session as root. This affects NAS520 V5.21(AASZ.4)C0, V5.21(AASZ.0)C0, V5.11(AASZ.3)C0, and V5.11(AASZ.0)C0.

NAS542 V5.11(ABAG.0)C0, V5.20(ABAG.1)C0, and V5.21(ABAG.3)C0.

NSA325 v2_V4.81(AALS.0)C0 and V4.81(AAAJ.1)C0.

NSA310 4.22(AFK.0)C0 and 4.22(AFK.1)C0.

NAS326 V5.21(AAZF.8)C0, V5.11(AAZF.4)C0, V5.11(AAZF.2)C0, and V5.11(AAZF.3)C0.

NSA310S V4.75(AALH.2)C0.

NSA320S V4.75(AANV.2)C0 and V4.75(AANV.1)C0.

NSA221 V4.41(AFM.1)C0.

and NAS540 V5.21(AATB.5)C0 and V5.21(AATB.3)C0.

HIGH · CVSS 8.8 EPSS 0.00128
Schedule remediation
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-287Improper Authentication
▤

Affected Products & Versions

4
zyxel nas326 firmware< v5.21\(aazf.9\)c0
zyxel nas520 firmware< v5.21\(aasz.5\)c0
zyxel nas540 firmware< v5.21\(aatb.6\)c0
zyxel nas542 firmware< v5.21\(abag.6\)c0
▣

Scoring & Timeline

8.8
HIGH · CVSS v3.1 · cve@mitre.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD06 Aug 2020 · 05:15 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
🔗

References & Sources

2
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://www.zyxel.com/support/Zyxel-security-advisory-for-NAS-remote-access-vulnerability.shtmlVendor Advisory
https://www.zyxel.com/us/en/support/security_advisories.shtmlVendor Advisory
Intelligence Graph · click any node to traverse
CVETechnique ActorTool Family
drag to reposition · click any node to traverse · button top-right enlarges
External lookups - second-class, for what we don’t hold ourselves
NVDCVE.orgCISAVulnersExploit-DBGitHub PoCVulnCheck KEVGreyNoise
Vulnerabilities
CISA KEV catalog
CWE weaknesses
CAPEC attack patterns
Package vulnerabilities
Threat intelligence
Threat actors
Tools & malware
ATT&CK techniques
IOCs
Detection & defense
Sigma rules
YARA rules
Atomic Red Team tests
D3FEND countermeasures
Compliance
NIST 800-53
ISO 27001:2022
SOC 2 TSC
PCI-DSS v4.0
CIS Controls v8.1
About
All capabilities
Live statistics
Data sources
Privacy policy
Terms of service
threatengine.sh  ·  Open-source threat intelligence platform  ·  100+ authoritative sources  ·  Every fact traces to its origin