CVE-2024-33881
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 · uneditedAn issue was discovered in VirtoSoftware Virto Bulk File Download 5.5.44 for SharePoint 2019. The Virto.SharePoint.FileDownloader/Api/Download.ashx isCompleted method allows an NTLMv2 hash leak via a UNC share pathname in the path parameter.
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 confidenceThe Download.ashx isCompleted method in Virto Bulk File Download 5.5.44 accepts a path parameter without proper validation, allowing attackers to supply a UNC share pathname (e.g., \\attacker-server\\share). When the SharePoint server processes this request, it attempts SMB authentication to the attacker-controlled UNC path, causing the NTLMv2 hash of the SharePoint service account to be transmitted to the attacker's server.
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= 5.5.44CVSS 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
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify if Virtosoftware SharePoint Bulk File Download is installedCheck the SharePoint farm solutions or farm features for the Virtosoftware Bulk File Download component. In SharePoint Management Shell, run: Get-SPSolution | Where-Object {$_.Name -like '*Virtosoftware*'} or check Add/Remove Programs on the server.Affected if The Virtosoftware SharePoint Bulk File Download solution is present in the SharePoint environment.
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Confirm the installed version is 5.5.44Retrieve the solution version. In SharePoint Management Shell, run: Get-SPSolution | Where-Object {$_.Name -like '*Virtosoftware*'} | Select-Object Name, Version. Compare the Version field to 5.5.44.Affected if The installed version is exactly 5.5.44.
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Locate the Download.ashx handlerCheck the virtual directories or ISAPI filters of the SharePoint web application for the Bulk File Download handler. The file typically exists under /_layouts/ or /_vti_bin/ directory. Use SharePoint Manager or check the web.config for handlers mapping to Download.ashx.Affected if The Download.ashx handler from the Bulk File Download component is registered and accessible.
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Verify the isCompleted method accepts path parameterInspect the deployed DLL (typically VirtoBulkFileDownload.dll) or the Download.ashx code if available. Check if the isCompleted method has a parameter that accepts a file or path value without validation.Affected if The isCompleted method processes a path parameter that could accept external input without validation.
The environment is affected if Virtosoftware SharePoint Bulk File Download version 5.5.44 is installed and the Download.ashx handler with the vulnerable isCompleted method is accessible.
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.
From vendor dataImplement strict input validation on the path parameter to reject UNC path formats (paths starting with '\\' or containing UNC-style patterns), or configure SMB signing and disable NTLM authentication at the domain level to prevent NTLM relay attacks.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2024-33881 — 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-2024-33881 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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- Version or environment caveats, and links to real fixes
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