dbcve.org
AsyncosOperating system · Cisco

CVE-2024-20435

HIGH · 7.8 CVSS v3.1 Published 2024-07-17
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
Remediation priority · High
Zero-click

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 CLI of Cisco AsyncOS for Secure Web Appliance could allow an authenticated, local attacker to execute arbitrary commands and elevate privileges to root. This vulnerability is due to insufficient validation of user-supplied input for the CLI. An attacker could exploit this vulnerability by authenticating to the system and executing a crafted command on the affected device. A successful exploit could allow the attacker to execute arbitrary commands on the underlying operating system and elevate privileges to root. To successfully exploit this vulnerability, an attacker would need at least guest credentials.

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

This is a local privilege escalation vulnerability in Cisco AsyncOS for Secure Web Appliance's CLI. An authenticated attacker with guest-level credentials can inject arbitrary commands through insufficiently validated CLI input, achieving root-level access on the underlying operating system.

MitigationApply the vendor-provided security patch or firmware update from Cisco for AsyncOS for Secure Web Appliance. Restrict CLI access to trusted personnel until the patch is applied.

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
AsyncosOperating system
Affected:= 11.7.0-406= 11.7.0-418= 11.7.1-006= 11.7.1-020= 11.7.1-049= 11.7.2-011= 11.8.0-414= 11.8.1-023= 11.8.3-018= 11.8.3-021= 12.0.1-268= 12.0.3-007

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

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. Identify the device as Cisco Secure Web Appliance
    Access the appliance admin web interface or CLI and identify the device model. The product name should be 'Cisco Secure Web Appliance' or 'Cisco AsyncOS for Secure Web Appliance'. Use the 'systemsetup' or 'archiver' CLI commands to display system information.
    Affected if The device is not a Cisco Secure Web Appliance running AsyncOS, then this CVE does not apply.
  2. Determine the installed AsyncOS version
    In the CLI, run the command 'version' or 'systemsetup' to display the firmware version. Alternatively, log into the web interface and check the System Administration > System Overview page for the AsyncOS version string.
    Affected if The version displayed matches one of the exact builds: 11.7.0-406, 11.7.0-418, 11.7.1-006, 11.7.1-020, 11.7.1-049, 11.7.2-011, 11.8.0-414, 11.8.1-023, 11.8.3-018, 11.8.3-021, 12.0.1-268, or 12.0.3-007.
  3. Verify CLI access is enabled and accessible
    Attempt to access the CLI via SSH on port 22 or console connection. Confirm the CLI service is running by checking with the 'telnet' command to port 22 or by viewing the network listener configuration in the web interface under Network > TCP Services.
    Affected if CLI access is disabled or unreachable, the specific exploitation path may not be directly available though the vulnerability still exists in the software.
  4. Check for guest-level user accounts
    In the CLI, run the 'userlist' or 'localusers' command to list all configured accounts. In the web interface, go to System Administration > User Management to view user accounts and their privilege levels. Identify accounts with 'Guest' or 'Guest User' role.
    Affected if Guest-level accounts exist on the appliance, an attacker with credentials to any such account could attempt command injection via the CLI.

If the device is a Cisco Secure Web Appliance running an AsyncOS version matching one of the listed builds, and guest-level CLI accounts exist, the environment is potentially affected by this privilege escalation vulnerability.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the vendor-provided security patch or firmware update from Cisco for AsyncOS for Secure Web Appliance. Restrict CLI access to trusted personnel until the patch is applied.

Fix this in Asyncos Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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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-2024-20435 in production — separate from our analysis above.

No notes yet

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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