CVE-2017-8540
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 · uneditedThe Microsoft Malware Protection Engine running on Microsoft Forefront and Microsoft Defender on Microsoft Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, 1607, and 1703, and Windows Server 2016, Microsoft Exchange Server 2013 and 2016, does not properly scan a specially crafted file leading to memory corruption. aka "Microsoft Malware Protection Engine Remote Code Execution Vulnerability", a different vulnerability than CVE-2017-8538 and CVE-2017-8541.
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 confidenceThe Microsoft Malware Protection Engine fails to properly scan specially crafted files, leading to memory corruption that can be exploited for remote code execution. The vulnerability exists in the scanning/parsing logic for malicious file types processed by Windows Defender and Forefront Client Security.
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>= 1.1.13701.0, < 1.1.13704.0all versions= 2013= 2016all versions= 2010all versionsall versionsall versionsall versionsCVSS 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
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/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 checksWork through these to decide whether this CVE applies to you.
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Check if Windows Defender or Security Essentials is installedOpen Settings > About or run 'Get-MpComputerStatus' in PowerShell to see if Microsoft antivirus is presentAffected if Either product is installed and the Malware Protection Engine version is 1.1.13701.0 through 1.1.13703.x
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Determine the Malware Protection Engine versionRun 'Get-MpComputerStatus' in PowerShell and look for the 'AntivirusSignatureVersion' or 'EngineVersion' field. Alternatively, check the version of mpengine.dll in the Windows Defender program folder (C:\ProgramData\Microsoft\Windows Defender\Definition Updates)Affected if The displayed engine version falls within 1.1.13701.0 to 1.1.13703.x
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Check if Exchange Server 2013 or 2016 is running malware scanningRun 'Get-TransportService | Get-MalwareFilteringServer' or check Exchange admin center to see if the Malware Agent is enabled. Verify via 'Get-ExchangeServer | Format-List Name, Edition, AdminDisplayVersion' to confirm Exchange versionAffected if Exchange Server 2013 or 2016 is running with the Malware Agent enabled and the built-in Malware Protection Engine is not patched
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Verify real-time protection is activeIn Windows Defender, go to Settings > Virus & threat protection > Virus & threat protection settings and confirm 'Real-time protection' is turned ON. In PowerShell, check 'Get-MpComputerStatus | Select-Object RealTimeProtectionEnabled'Affected if Real-time protection is enabled and the engine version is in the vulnerable range
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Check System Center Endpoint Protection or Microsoft Endpoint ProtectionOpen the SCEP/SEP client console or check registry key HKLM\SOFTWARE\Microsoft\Microsoft Security Client\Version for the engine versionAffected if Any version of these products is installed with the Malware Protection Engine in the vulnerable version range
A system is affected if any Microsoft antivirus product (Defender, Security Essentials, Exchange malware scanning, etc.) with a Malware Protection Engine version between 1.1.13701.0 and 1.1.13703.x is installed and the scanning engine is active.
Generated from the published advisory. Verify against your own configuration.
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.
dbcve · scoped1.1.13704.0
Apply the Microsoft security update to ensure the Malware Protection Engine is updated to the latest version via Windows Update or Microsoft Update. For Exchange servers, apply the relevant cumulative updates.
Malware Protection Engine version 1.1.13704.0 or later
- Verify the current Malware Protection Engine version by running: mpcmdrun.exe -GetEngineVersion -Date <date> (or check via the Windows Security app/Status page)
- Ensure automatic updates are enabled for Windows Defender/Microsoft Security Essentials
- For enterprise environments, manually update the Malware Protection Engine to version 1.1.13704.0 or later via your management console (SCCM, Intune, or Group Policy)
- Restart the Windows Defender/Microsoft Security Essentials service after the update: net stop winDefend && net start winDefend
- Confirm the update was successful by verifying the engine version is >= 1.1.13704.0
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing8.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,288.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-8540 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2017-8540 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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