Cyber Resilience

CVE-2023-5376

Auth Bypass in Korenix Jetnet 7628Xp-4F-Us Firmware 1.0 … 1.1

Published
09 January 2024
Modified
08 October 2025
Patch / advisory
CVSS Score v3.1 8.6
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
EPSS Score 0.014 70th percentile
Risk Priority 64 floored blend · peak EPSS

Summary

CVE-2023-5376 is a high-severity Missing Authentication for Critical Function (CWE-306) vulnerability in Korenix Jetnet 7628Xp-4F-Us Firmware. Its CVSS base score is 8.6 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 30% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to AC-14 (Permitted Actions Without Identification or Authentication) and IA-2 (Identification and Authentication (Organizational Users)) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

An Improper Authentication vulnerability in Korenix JetNet TFTP allows abuse of this service. This issue affects JetNet devices older than firmware version 2024/01.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1133 External Remote Services Persistence
Adversaries may leverage external-facing remote services to initially access and/or persist within a network.
T1040 Network Sniffing Credential Access
Adversaries may passively sniff network traffic to capture information about an environment, including authentication material passed over the network.
T1134 Access Token Manipulation Stealth
Adversaries may modify access tokens to operate under a different user or system security context to perform actions and bypass access controls.
T1185 Browser Session Hijacking Collection
Adversaries may take advantage of security vulnerabilities and inherent functionality in browser software to change content, modify user-behaviors, and intercept information as part of various browser session hijacking techniques.
T1505.003 Web Shell Persistence
Adversaries may backdoor web servers with web shells to establish persistent access to systems.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-5347Same product: Korenix Jetnet 4508
CVE-2026-3194Shared CWE-287, CWE-306
CVE-2026-4187Shared CWE-287, CWE-306
CVE-2026-7042Shared CWE-287, CWE-306
CVE-2024-42462Shared CWE-287, CWE-306
CVE-2025-11661Shared CWE-287, CWE-306
CVE-2026-18810Shared CWE-287, CWE-306
CVE-2023-27377Shared CWE-287, CWE-306
CVE-2026-15491Shared CWE-287, CWE-306
CVE-2025-15346Shared CWE-287, CWE-306

Affected Assets

korenix
jetnet 5310g firmware
2.6
korenix
jetnet 4508 firmware
2.3
korenix
jetnet 4508i-w firmware
1.3
korenix
jetnet 4508-w firmware
2.3
korenix
jetnet 4508if-s firmware
1.3
korenix
jetnet 4508if-m firmware
1.3
korenix
jetnet 4508if-sw firmware
1.3
korenix
jetnet 4508if-mw firmware
1.3
korenix
jetnet 4508f-m firmware
2.3
korenix
jetnet 4508f-s firmware
2.3
+32 more product configuration(s) — see NVD for full list

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 14 hardening rules · 5 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V6.4.4
  • V6.5.4
  • V6.5.5
  • V6.5.7

Mitigating Controls (NIST 800-53 r5) AI

Directly mandates unique identification and authentication of users before access to functions requiring identity.

Requires unique identification and authentication of devices before establishing connections, preventing unauthenticated device claims.

Extends the same authentication requirement to non-organizational users accessing critical functionality.

Requires authentication of services before they can invoke or expose critical functions.

Explicitly identifies and limits actions permitted without authentication, preventing critical functions from being exposed.

Manages authenticators with verification and secure distribution, reducing opportunities for improper authentication.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-03 full match
prevents

Directly requires authentication of users/services/hardware, which eliminates missing authentication for critical functions.

PR.AA-04 mostly match
prevents

PR.AA-04 directly enables verification of identity assertions (mostly preventing CWE-287 in that scope) yet leaves many other authentication failure modes unaddressed (only partial prevention overall).

PR.AA-01 partial match
prevents

Managing identities and credentials is a prerequisite for authentication but does not itself enforce it on critical functions.

PR.AA-02 partial match
prevents

PR.AA-02 ensures valid enrollment and unique credential binding, which reduces some improper-auth risks at issuance time but leaves runtime claim verification untouched, so each direction only partially addresses the other.

PR.AA-05 partial match
prevents

Defining and enforcing authorizations assumes prior authentication and therefore only partially mitigates the absence of authentication.

PR.IR-01 partial match
prevents

Protecting networks from unauthorized access can be undermined by missing authentication but does not address the root authentication gap.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

The control explicitly calls for authentication before any critical function is reached, eliminating the possibility of bypassing authentication for high-value operations.

prevents

Verifying user identity before issuing replacement credentials and forcing changes after compromise reduces the likelihood that authentication bypass can be achieved through stolen or weak credentials.

prevents

Mandating segregated approval and oversight for non-human identities reduces the chance that weak or orphaned credentials can be exploited for unauthorized authentication.

prevents

Mandating authentication requirements for critical functions at the requirements-gathering stage ensures that essential operations are not left unprotected by missing login or verification mechanisms.

mitigates

Mandating authentication for network services and critical functions stops attackers from invoking sensitive operations without credentials, closing gaps where authentication is absent for important capabilities.

prevents

Security requirements specified early and verified through testing drive the consistent implementation of authentication mechanisms, decreasing the likelihood that authentication steps are omitted or incorrectly applied.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248827 OL 8 must not have the rsh-server package installed. prevents CWE-287, CWE-306
  • V-248585 OL 8 must require reauthentication when using the "sudo" command. prevents CWE-306
RHEL 7 (4 rules)
  • V-204425 The Red Hat Enterprise Linux operating system must be configured so that the SSH daemon does not allow authentication using an empty password. prevents CWE-287
  • V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. prevents CWE-287, CWE-306
  • V-204424 The Red Hat Enterprise Linux operating system must not allow accounts configured with blank or null passwords. prevents CWE-287
RHEL 8 (2 rules)
  • V-230492 RHEL 8 must not have the rsh-server package installed. prevents CWE-287, CWE-306
  • V-237643 RHEL 8 must require re-authentication when using the "sudo" command. prevents CWE-306
Ubuntu 22.04 (1 rule)
  • V-260470 Ubuntu 22.04 LTS, when booted, must require authentication upon booting into single-user and maintenance modes. prevents CWE-287
Ubuntu 24.04 (2 rules)
  • V-270675 Ubuntu 24.04 LTS when booted must require authentication upon booting into single-user and maintenance modes. prevents CWE-287
  • V-270714 Ubuntu 24.04 LTS must not allow accounts configured in Pluggable Authentication Modules (PAM) with blank or null passwords. prevents CWE-287

References