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Secure Firewall Management CenterApplication · Cisco

CVE-2018-0384

MEDIUM · 5.8 CVSS v3.0 Published 2018-07-16
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
67/100
Remediation priority · Elevated
Remotely reachable No privileges 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 detection engine of Cisco FireSIGHT System Software could allow an unauthenticated, remote attacker to bypass a URL-based access control policy that is configured to block traffic for an affected system. The vulnerability exists because the affected software incorrectly handles TCP packets that are received out of order when a TCP SYN retransmission is issued. An attacker could exploit this vulnerability by sending a maliciously crafted connection through an affected device. A successful exploit could allow the attacker to bypass a URL-based access control policy that is configured to block traffic for the affected system. Cisco Bug IDs: CSCvh84511.

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 vulnerability in Cisco FireSIGHT System Software's detection engine allows unauthenticated remote attackers to bypass URL-based access control policies. The flaw occurs when the system incorrectly processes TCP packets received out of order during a TCP SYN retransmission, causing the detection engine to fail in properly evaluating and blocking malicious traffic that should be filtered.

MitigationApply the vendor patch from Cisco for CSCvh84511. Until patched, implement additional network-layer filtering or monitoring as a compensating control to detect anomalous TCP behaviors.

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 Firewall Management CenterApplication
Affected:= 6.0.0= 6.1.0= 6.2.0= 6.2.1= 6.2.2

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
None
Scope
Changed
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/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. Identify the installed Cisco Secure Firewall Management Center version
    Log into the FMC web interface and navigate to System > About, or run 'show version' via CLI on the management center. Record the exact version number displayed.
    Affected if The installed version is exactly 6.0.0, 6.1.0, 6.2.0, 6.2.1, or 6.2.2.
  2. Confirm URL-based access control policies are configured
    In the FMC web interface, navigate to Policies > Access Control. Verify if any access control policies exist and are enabled. Check if any of these policies have URL filtering rules or URL-based conditions configured.
    Affected if Access control policies with URL filtering are active and the system is protecting traffic.
  3. Verify the detection engine is enabled for traffic inspection
    In the FMC, go to Policies > Access Control and select the active policy. Confirm the policy is set to inspect traffic (not set to 'trust' or 'block all'). Check that the Intrusion Policy attached to the access control rule is not set to 'disable'.
    Affected if The detection engine is actively inspecting traffic and evaluating access control rules.
  4. Check for out-of-order TCP packet handling in network configuration
    Review any network tap, span port, or inline tap configurations that feed traffic to the FireSIGHT/FMC. There is no direct CLI command to verify this vulnerability exists; it manifests during live traffic when TCP SYN retransmissions occur out of order.
    Affected if The system is receiving live traffic flows that could trigger the out-of-order TCP processing behavior.

You are affected if your FMC version matches exactly 6.0.0, 6.1.0, 6.2.0, 6.2.1, or 6.2.2 AND you have active URL-based access control policies with the detection engine enabled for traffic inspection.

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 patch from Cisco for CSCvh84511. Until patched, implement additional network-layer filtering or monitoring as a compensating control to detect anomalous TCP behaviors.

Fix this in Secure Firewall Management Center Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,480
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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-2018-0384 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
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  • Version or environment caveats, and links to real fixes
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