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Email Security ApplianceApplication · Cisco

CVE-2018-0419

HIGH · 7.5 CVSS v3.0 Published 2018-08-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
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 certain attachment detection mechanisms of Cisco Email Security Appliances (ESA) could allow an unauthenticated, remote attacker to bypass the filtering functionality of an affected system. The vulnerability is due to the improper detection of content within executable (EXE) files. An attacker could exploit this vulnerability by sending a customized EXE file that is not recognized and blocked by the ESA. A successful exploit could allow an attacker to send email messages that contain malicious executable files to unsuspecting users. Cisco Bug IDs: CSCvh03786.

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 Email Security Appliance's attachment detection mechanisms allows malicious executable (EXE) files to bypass content filtering. The ESA fails to properly detect and block certain EXE file content, enabling an unauthenticated remote attacker to deliver malicious attachments to end users via email.

MitigationApply the Cisco security patch for CSCvh03786 when available. As an interim workaround, consider implementing additional email filtering layers or restricting EXE attachments at the gateway until the patch can be deployed.

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
Email Security ApplianceApplication
Affected:all versions

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
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/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. Confirm Cisco ESA is deployed
    Identify if Cisco Email Security Appliance is in use in your environment. Check product model, GUI login page, or network documentation for 'Cisco Email Security Appliance' or 'ESA' branding.
    Affected if The product is confirmed as Cisco Email Security Appliance and all versions are vulnerable.
  2. Verify attachment scanning is enabled
    Access the ESA web interface or CLI. Navigate to Incoming Mail Policies > Attachment Filtering, or use the command: 'filters show' or check the 'attachment' settings in the mail policy configuration.
    Affected if Attachment scanning is enabled and the CVE allows EXE files to bypass this protection.
  3. Check EXE file type is included in blocked extensions
    In ESA GUI, go to Mail Policies > Incoming Mail Policy > Attachment Filtering tab. Verify if '.exe' extension is listed in the 'Blocked File Types' or check via CLI with: 'filters list' or 'attachmentconfig'.
    Affected if EXE files are not explicitly blocked or the file extension filtering is not configured.
  4. Test outbound mail for EXE attachment detection
    Send a test email with a .exe file attachment through the ESA to a test account and verify if the attachment is detected, blocked, or quarantined. Monitor the message tracking logs in ESA.
    Affected if The EXE attachment is delivered without being detected, blocked, or quarantined by the ESA content filters.
  5. Review message tracking for delivered EXE attachments
    In ESA, use Message Tracking or Centralized Logging to search for recently delivered emails with .exe attachments. Look for any entries where 'EXE' or 'executable' appears in attachment metadata.
    Affected if Emails with EXE attachments were delivered to end users without being flagged or blocked.

If Cisco ESA is deployed with attachment filtering enabled but EXE files are still being delivered to end users without detection, the environment is likely affected by this 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 Cisco security patch for CSCvh03786 when available. As an interim workaround, consider implementing additional email filtering layers or restricting EXE attachments at the gateway until the patch can be deployed.

Fix this in Email Security Appliance Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,440
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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-2018-0419 in production — separate from our analysis above.

No notes yet

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What this is

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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
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