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Secure Firewall Management CenterApplication · Cisco

CVE-2017-12300

MEDIUM · 5.8 CVSS v3.0 Published 2017-11-16
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 SNORT detection engine of Cisco Firepower System Software could allow an unauthenticated, remote attacker to bypass a file policy that is configured to block the Server Message Block Version 2 (SMB2) protocol. The vulnerability is due to the incorrect detection of an SMB2 file when the detection is based on the length of the file. An attacker could exploit this vulnerability by sending a crafted SMB2 transfer request through the targeted device. A successful exploit could allow the attacker to bypass filters that are configured to block SMB2 traffic. Cisco Bug IDs: CSCve58398.

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 · moderate confidence

A vulnerability in the SNORT detection engine of Cisco Firepower System Software allows an unauthenticated remote attacker to bypass file policies that block SMB2 protocol. The flaw is in how SMB2 files are detected when detection relies on file length values - the detection logic incorrectly processes crafted SMB2 transfer requests, allowing the traffic to evade filters.

MitigationApply the Cisco patch for CSCve58398 to update the SNORT detection engine in Cisco Firepower System Software. Verify that file policies correctly block SMB2 traffic after the update.

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:= 2.9.9= 2.9.10= 2.9.11= 2.9.12

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 Cisco Secure Firewall Management Center version
    Log into the Firepower Management Center web interface and navigate to System > About > Updates, or run 'show version' via CLI to display the installed software version
    Affected if The installed version is 2.9.9, 2.9.10, 2.9.11, or 2.9.12
  2. Locate configured file policies
    In the Firepower Management Center, go to Policies > Access Control > File Policy to view all configured file policies
    Affected if At least one file policy exists that is set to block or detect SMB2 traffic
  3. Verify file policy is assigned to access control rule
    Navigate to Policies > Access Control > Access Control and examine the rule that uses the identified file policy; confirm the rule applies to the relevant traffic zones
    Affected if A file policy that blocks SMB2 is actively assigned to an access control rule applied to traffic
  4. Confirm SMB2 traffic inspection is enabled
    Check the access control rule settings to verify that File Policy is enabled and that the rule does not exclude SMB2 traffic from inspection
    Affected if SMB2 traffic is subject to the file policy but the SNORT engine may incorrectly process the file length values

You are affected if your Cisco Secure Firewall Management Center runs version 2.9.9-2.9.12 and you have an active file policy configured to block or inspect SMB2 traffic.

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 Cisco patch for CSCve58398 to update the SNORT detection engine in Cisco Firepower System Software. Verify that file policies correctly block SMB2 traffic after the update.

Fix this in Secure Firewall Management Center Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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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-2017-12300 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
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