Cyber Resilience

CVE-2023-20025

Auth Bypass in Cisco Rv016 Firmware

Published
20 January 2023
Modified
07 April 2025
Patch / advisory
CVSS Score v3.1 9.0
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H
EPSS Score 0.016 74th percentile
Risk Priority 67 floored blend · peak EPSS

Summary

CVE-2023-20025 is a critical-severity Using Referer Field for Authentication (CWE-293) vulnerability in Cisco Rv016 Firmware. Its CVSS base score is 9.0 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 26% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

A vulnerability in the web-based management interface of Cisco Small Business RV016, RV042, RV042G, and RV082 Routers could allow an unauthenticated, remote attacker to bypass authentication on an affected device. This vulnerability is due to improper validation of user input…

more

within incoming HTTP packets. An attacker could exploit this vulnerability by sending a crafted HTTP request to the web-based management interface. A successful exploit could allow the attacker to bypass authentication and gain root access on the underlying operating system.

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.
T1557 Adversary-in-the-Middle Credential Access
Adversaries may attempt to position themselves between two or more networked devices using an adversary-in-the-middle (AiTM) technique to support follow-on behaviors such as [Network Sniffing](https://attack.
T1557.001 Name Resolution Poisoning and SMB Relay Credential Access
By responding to LLMNR/NBT-NS/mDNS network traffic, adversaries may spoof an authoritative source for name resolution to force communication with an adversary controlled system.
T1036 Masquerading Stealth
Adversaries may attempt to manipulate features of their artifacts to make them appear legitimate or benign to users and/or security tools.
T1036.001 Invalid Code Signature Stealth
Adversaries may attempt to mimic features of valid code signatures to increase the chance of deceiving a user, analyst, or tool.
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.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-20026Same product: Cisco Rv016
CVE-2024-20299Same vendor: Cisco
CVE-2024-20384Same vendor: Cisco
CVE-2023-20245Same vendor: Cisco
CVE-2024-20363Same vendor: Cisco
CVE-2024-20297Same vendor: Cisco
CVE-2023-20256Same vendor: Cisco
CVE-2023-20137Same product: Cisco Rv016
CVE-2023-20148Same product: Cisco Rv016
CVE-2023-20145Same product: Cisco Rv016

Affected Assets

cisco
rv016 firmware
all versions
cisco
rv042 firmware
all versions
cisco
rv042g firmware
all versions
cisco
rv082 firmware
all versions

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 3 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V6.4.3
  • V10.4.16
  • V10.5.1
  • V11.4.3

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-290

Reveals spoofed logon attempts through unexpected previous logon timestamps upon legitimate login.

addresses: CWE-290

Training specifically addresses recognizing spoofed communications and phishing that enable authentication bypass.

addresses: CWE-290

Requiring verifiable identity evidence at appropriate assurance levels makes it substantially harder for attackers to successfully spoof or impersonate users to obtain accounts.

addresses: CWE-290

Unique device authentication makes successful spoofing of device identity substantially more difficult to achieve.

addresses: CWE-290

Unique identification of non-organizational users reduces the feasibility of authentication bypass by spoofing.

addresses: CWE-290

Unique identification and authentication of services before communications makes spoofing of service identities substantially harder.

addresses: CWE-290

Isolated trusted path ensures the user interacts only with genuine system components, preventing spoofing of authentication interfaces or prompts.

addresses: CWE-290

Directly counters DNS response spoofing by requiring cryptographic origin authentication artifacts from the authoritative source.

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-04 full match
prevents

Protecting, conveying, and verifying identity assertions specifically prevents the spoofing that enables authentication bypass.

PR.AA-03 mostly match
prevents

Proper authentication mechanisms directly replace reliance on the spoofable Referer header.

PR.AA-02 partial match
prevents

Proofing and binding identities reduces spoofing opportunities during enrollment but does not address runtime authentication implementation flaws.

PR.AA-05 partial match
prevents

Authorization policy enforcement reduces the chance that a weak Referer check is accepted as sufficient.

PR.PS-06 partial match
prevents

Secure-development practices discourage or prohibit using the Referer header for authentication decisions.

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

Secure authentication explicitly requires strong, non-spoofable mechanisms, directly preventing reliance on the Referer header.

degrades

Authentication information management directly addresses credential handling that prevents spoofing.

finds

Security testing can detect spoofing vulnerabilities but does not prevent them by itself.

prevents

Access control policy reduces spoofing opportunities but does not prescribe authentication mechanisms.

prevents

Identity management supports unique identities but does not guarantee resistance to spoofing.

prevents

Access rights assignment limits exposure but does not enforce authentication strength.

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 (1 rule)
  • V-248827 OL 8 must not have the rsh-server package installed. prevents CWE-290
RHEL 7 (1 rule)
  • V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. prevents CWE-290
RHEL 8 (1 rule)
  • V-230492 RHEL 8 must not have the rsh-server package installed. prevents CWE-290

References