dbcve.org
Secure Firewall Management CenterApplication · Cisco

CVE-2018-15397

MEDIUM · 6.8 CVSS v3.1 Published 2018-10-05
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
77/100
Remediation priority · High
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 implementation of Traffic Flow Confidentiality (TFC) over IPsec functionality in Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to restart unexpectedly, resulting in a denial of service (DoS) condition. The vulnerability is due to an error that may occur if the affected software renegotiates the encryption key for an IPsec tunnel when certain TFC traffic is in flight. An attacker could exploit this vulnerability by sending a malicious stream of TFC traffic through an established IPsec tunnel on an affected device. A successful exploit could allow the attacker to cause a daemon process on the affected device to crash, which could cause the device to crash and result in a DoS condition.

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 denial of service vulnerability exists in Cisco ASA and FTD software's implementation of Traffic Flow Confidentiality (TFC) over IPsec. When the software renegotiates the encryption key for an IPsec tunnel while certain TFC traffic is in flight, an error occurs that causes a daemon process to crash, leading to an unexpected device restart.

MitigationApply the Cisco security update/patch for this vulnerability. Until patched, monitor for unexpected device restarts and consider restricting IPsec tunnel establishment to trusted peers.

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:= 6.2.2
Adaptive Security Appliance SoftwareOperating system
Affected:= 9.6.4= 9.8.2= 9.9.1= 9.9.1\(1\)

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
High
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/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 product and software version
    For ASA: run 'show version' or 'show version | include Version'. For FTD: access via FMC or run 'show version' on the FTD device.
    Affected if Version matches 9.6.4, 9.8.2, 9.9.1, or 9.9.1(1) for ASA, or 6.2.2 for Secure Firewall Management Center (FMC)
  2. Determine if IPsec tunnels with TFC are configured
    On ASA, run 'show crypto ipsec sa' to list active IPsec SAs and look for TFC-related parameters. Also check tunnel group and crypto map configurations for TFC enablement.
    Affected if Any IPsec tunnels are configured with TFC (Traffic Flow Confidentiality) enabled
  3. Check for crash logs or reload history
    Run 'show crashdump' to check for crash information. Run 'show reload' or check logging buffers for unexpected reload events.
    Affected if Device has experienced unexpected reloads or crashes that coincide with IPsec key renegotiation periods
  4. Monitor daemon health during key renegotiation
    Use 'show process cpu history' and 'show process memory' before and during IPsec tunnel activity. Check 'show logging' for error messages related to IPsec or TFC daemons.
    Affected if Daemon crashes occur specifically when IPsec tunnels renegotiate keys while TFC traffic is active

You are affected if your device runs an affected version (ASA 9.6.4, 9.8.2, 9.9.1, 9.9.1(1) or FMC 6.2.2) AND you have IPsec tunnels configured with TFC enabled, especially if you observe unexpected reloads during tunnel key renegotiation.

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 security update/patch for this vulnerability. Until patched, monitor for unexpected device restarts and consider restricting IPsec tunnel establishment to trusted peers.

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
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2018-15397 — 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-2018-15397 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