Security Resilience

CVE-2024-20391

Access Control in Cisco Secure Client ≤ 5.1.3.62

Access Control
Published
15 May 2024
Modified
22 July 2025
Patch / advisory
View advisory
CVSS Score v3.1 6.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0035 27th percentile
Risk Priority 50 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-2024-20391 is a medium-severity Missing Authentication for Critical Function (CWE-306) vulnerability in Cisco Secure Client. Its CVSS base score is 6.8 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique System Service Discovery (T1007); ranked at the 27th 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 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)

A07:2025 Authentication Failures

EU & UK References

Vulnerability Data

A vulnerability in the Network Access Manager (NAM) module of Cisco Secure Client could allow an unauthenticated attacker with physical access to an affected device to elevate privileges to SYSTEM. This vulnerability is due to a lack of authentication on…

more

a specific function. A successful exploit could allow the attacker to execute arbitrary code with SYSTEM privileges on an affected device.

CWE(s)
CWE-306

Related Threats

MITRE ATT&CK Enterprise Techniques

T1007 System Service Discovery Discovery
Adversaries may try to gather information about registered local system services.
attack.mitre.org →
T1010 Application Window Discovery Discovery
Adversaries may attempt to get a listing of open application windows.
attack.mitre.org →
T1016 System Network Configuration Discovery Discovery
Adversaries may look for details about the network configuration and settings, such as IP and/or MAC addresses, of systems they access or through information discovery of remote systems.
attack.mitre.org →
T1027.004 Compile After Delivery Stealth
Adversaries may attempt to make payloads difficult to discover and analyze by delivering files to victims as uncompiled code.
attack.mitre.org →
T1027.006 HTML Smuggling Stealth
Adversaries may smuggle data and files past content filters by hiding malicious payloads inside of seemingly benign HTML files.
attack.mitre.org →
T1027.007 Dynamic API Resolution Stealth
Adversaries may obfuscate then dynamically resolve API functions called by their malware in order to conceal malicious functionalities and impair defensive analysis.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-53378Same product: Microsoft Windows
CVE-2023-27497Same product: Microsoft Windows
CVE-2023-31132Same product: Microsoft Windows
CVE-2023-29485Same product: Microsoft Windows
CVE-2026-0247Same product: Microsoft Windows
CVE-2025-48814Same vendor: Microsoft
CVE-2024-43488Same vendor: Microsoft
CVE-2026-56164Same vendor: Microsoft
CVE-2023-20126Same vendor: Cisco
CVE-2026-64921Same vendor: Microsoft

Affected Assets

cisco
secure client
≤ 5.1.3.62

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 6 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V6.2.3
  • V6.4.4
  • V10.4.16
  • V12.1.3

Mitigating Controls (NIST 800-53 r5) AI

IA-2 Identification and Authentication (Organizational Users) good match

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

IA-8 Identification and Authentication (Non-organizational Users) good match

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

IA-9 Service Identification and Authentication good match

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

AC-14 Permitted Actions Without Identification or Authentication good match

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

AC-3 Access Enforcement partial match

Access enforcement requires prior authentication before any authorization decision for critical functions.

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-01 partial match
blocks

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

PR.AA-03 partial match
blocks

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

PR.AA-05 partial match
blocks

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

PR.IR-01 partial match
blocks

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.

A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.5.8 Information security in project management partial match
blocks

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.

A.8.10 Information deletion partial match
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 (2 rules)
  • V-248585 OL 8 must require reauthentication when using the "sudo" command. blocks CWE-306
  • V-248827 OL 8 must not have the rsh-server package installed. blocks CWE-306
RHEL 7 (2 rules)
  • V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. blocks CWE-306
  • V-237635 The Red Hat Enterprise Linux operating system must require re-authentication when using the "sudo" command. blocks CWE-306
RHEL 8 (2 rules)
  • V-230492 RHEL 8 must not have the rsh-server package installed. blocks CWE-306
  • V-237643 RHEL 8 must require re-authentication when using the "sudo" command. blocks CWE-306

References