dbcve.org
Secure ClientApplication · Cisco

CVE-2024-20337

HIGH · 8.2 CVSS v3.1 Published 2024-03-06
Fix available
A fix is available. Upgrade to 4.10.08025 / 5.1.2.42 or later.
See remediation →
89/100
Remediation priority · High
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability in the SAML authentication process of Cisco Secure Client could allow an unauthenticated, remote attacker to conduct a carriage return line feed (CRLF) injection attack against a user. This vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by persuading a user to click a crafted link while establishing a VPN session. A successful exploit could allow the attacker to execute arbitrary script code in the browser or access sensitive, browser-based information, including a valid SAML token. The attacker could then use the token to establish a remote access VPN session with the privileges of the affected user. Individual hosts and services behind the VPN headend would still need additional credentials for successful access.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A CRLF injection vulnerability exists in the SAML authentication flow of Cisco Secure Client. Attackers craft malicious links that, when clicked by a user during VPN session establishment, inject arbitrary headers/scripts into the SAML response. This enables XSS execution in the user's browser and theft of valid SAML tokens, which attackers can then use to hijack the user's VPN session with full privileges.

MitigationApply the vendor-supplied patch from Cisco when released; until then, train users to avoid clicking untrusted links during VPN session establishment and consider additional session integrity controls.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Secure ClientApplication
Affected:>= 4.10.04065, < 4.10.08025>= 5.0.00529, < 5.1.2.42

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Determine Cisco Secure Client installed version
    Open Windows Settings > Apps & Features (or macOS Applications folder), find Cisco Secure Client, and note the version number. Alternatively, run 'ampdefenseservice --version' or check the program's properties in the installation directory.
    Affected if The installed version falls within 4.10.04065 to 4.10.08025, or 5.0.00529 to 5.1.2.41 (inclusive of the lower bounds, exclusive of the upper bounds).
  2. Identify SAML authentication configuration
    Examine the Cisco Secure Client profile or configuration files for SAML IdP (Identity Provider) settings. In the Windows client, access this via the profile editor or check registry keys under HKLM\Software\Cisco Systems, Inc.\Cisco Secure Client\SAML. On macOS, check /opt/cisco/secureclient/configuration/.
    Affected if A SAML IdP is configured and enabled as an authentication method for VPN connections.
  3. Check for vulnerable SAML component
    Inspect the Cisco Secure Client installation directory for the SAML authentication DLLs/modules, specifically samlauth.dll or similar SAML handler binaries in the bin or lib subdirectory of the installation path.
    Affected if The SAML authentication module exists and is present in the installation (this confirms the attack surface is present).
  4. Review browser/webview integration logs
    Access Cisco Secure Client logs in the system temp folder or /var/log/cisco/secureclient/ (macOS/Linux). Search for SAML response processing entries or any evidence of malformed HTTP headers in authentication flows.
    Affected if Logs show SAML authentication attempts occurring, confirming the vulnerable code path could be exercised.

A user is affected if Cisco Secure Client is installed with a version matching the affected ranges AND SAML authentication is enabled, exposing the SAML authentication flow to CRLF injection exploitation.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 4.10.08025 / 5.1.2.42 or later
Fixed in 4.10.080255.1.2.42
Interim mitigation

Apply the vendor-supplied patch from Cisco when released; until then, train users to avoid clicking untrusted links during VPN session establishment and consider additional session integrity controls.

Recommended fix High confidence

Secure Client 4.10.08025 or later (for 4.10.x users); Secure Client 5.1.2.42 or later (for 5.0.x and 5.1.x users)

  1. 1. Identify the currently installed Cisco Secure Client version by checking About or version information in the client
  2. 2. If running version 4.10.x (between 4.10.04065 and 4.10.08024 inclusive), plan upgrade to version 4.10.08025 or later
  3. 3. If running version 5.0.x (between 5.0.00529 and 5.1.2.41 inclusive), plan upgrade to version 5.1.2.42 or later
  4. 4. If running version 5.1.x below 5.1.2.42, upgrade to version 5.1.2.42 or later
  5. 5. Download the appropriate updated Cisco Secure Client installer from the Cisco Software Download center (software.cisco.com) or your authorized Cisco distribution channel
  6. 6. Test the upgrade in a non-production environment first to verify compatibility with your VPN infrastructure
  7. 7. Deploy the upgrade to production systems following your organization's change management process
  8. 8. After upgrade, verify the SAML authentication functionality works correctly and the client version reflects the patched release
Caveat Review Cisco release notes for version 4.10.08025 and 5.1.2.42 for any configuration or behavioral changes that may affect existing deployments

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Secure Client Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2024-20337 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-20337 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data