Security Resilience

CVE-2024-21494

Auth Bypass in Greenpau Caddy-Security

Published
17 February 2024
Modified
17 June 2026
CVSS Score v3.1 5.4
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
EPSS Score 0.0052 43th percentile
Risk Priority 44 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2024-21494 is a medium-severity Authentication Bypass by Spoofing (CWE-290) vulnerability in Greenpau Caddy-Security. Its CVSS base score is 5.4 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Junk Data (T1001.001); ranked at the 43th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to IA-2 (Identification and Authentication (Organizational Users)) and IA-3 (Device Identification and Authentication) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

All versions of the package github.com/greenpau/caddy-security are vulnerable to Authentication Bypass by Spoofing via the X-Forwarded-For header due to improper input sanitization. An attacker can spoof an IP address used in the user identity module (/whoami API endpoint). This could…

more

lead to unauthorized access if the system trusts this spoofed IP address.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001.001 Junk Data Command And Control
Adversaries may add junk data to protocols used for command and control to make detection more difficult.
T1001.003 Protocol or Service Impersonation Command And Control
Adversaries may impersonate legitimate protocols or web service traffic to disguise command and control activity and thwart analysis efforts.
T1003.003 NTDS Credential Access
Adversaries may attempt to access or create a copy of the Active Directory domain database in order to steal credential information, as well as obtain other information about domain members such as devices, users, and access rights.
T1003.004 LSA Secrets Credential Access
Adversaries with SYSTEM access to a host may attempt to access Local Security Authority (LSA) secrets, which can contain a variety of different credential materials, such as credentials for service accounts.
T1003.005 Cached Domain Credentials Credential Access
Adversaries may attempt to access cached domain credentials used to allow authentication to occur in the event a domain controller is unavailable.
T1006 Direct Volume Access Stealth
Adversaries may directly access a volume to bypass file access controls and file system monitoring.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-5001Shared CWE-79
CVE-2023-5705Shared CWE-79
CVE-2023-0280Shared CWE-79
CVE-2023-0309Shared CWE-79
CVE-2023-42478Shared CWE-79
CVE-2023-6075Shared CWE-79
CVE-2023-4173Shared CWE-79
CVE-2023-46199Shared CWE-79
CVE-2023-30482Shared CWE-79
CVE-2023-2498Shared CWE-79

Affected Assets

greenpau
caddy-security
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
  • V11.4.3
  • V1.1.2

Mitigating Controls (NIST 800-53 r5) AI

Proper unique identification and authentication of users directly stops spoofing-based bypass of authentication.

Device identification and authentication before connection prevents spoofing of devices to bypass auth.

Authentication of non-organizational users blocks external spoofing attempts against the scheme.

Authenticator management ensures credentials cannot be easily spoofed or reused to bypass authentication.

Developer testing and evaluation can discover missing or incorrect input neutralization through targeted web-application tests.

Input validation directly enforces neutralization of untrusted data before it reaches web output generation.

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.PS-06 mostly match
blocks

Secure SDLC practices directly target introduction of XSS via coding standards/testing (mostly), yet the single broad outcome leaves many specific neutralization vectors unaddressed (partial).

PR.AA-02 partial match
blocks

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

PR.AA-03 partial match
blocks

Requiring authentication of users/services/hardware directly counters spoofing-based bypass when strong methods are used.

PR.AA-04 partial match
blocks

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

PR.PS-02 partial match
blocks

Patching and EOL replacement can remediate known XSS instances in libraries or frameworks (partial) but do nothing to enforce input neutralization in application code (none).

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.

removes
blocks

A.5.15 only requires that an access control policy and requirements be defined and communicated; it does not itself implement, enforce or configure any authentication scheme that would stop spoofing attacks from bypassing authentication, so the weakness remains fully exploitable.

blocks

A.5.16 manages the lifecycle, uniqueness, and accountability of identities; it does not implement or strengthen authentication schemes against spoofing, so the CWE-290 exploit remains possible even when identities are correctly provisioned and tracked.

blocks

Authentication information management directly addresses credential handling that prevents spoofing.

blocks

A.5.18 governs the provisioning, review, and revocation of already-granted access rights to authenticated identities; it has no bearing on whether an authentication scheme can be spoofed or bypassed before any rights are assigned.

removes

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` (higher-evidence rows only; rows rated `none` are excluded).

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

References