CVE-2017-11157
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 · uneditedMultiple untrusted search path vulnerabilities in the installer in Synology Cloud Station Backup before 4.2.5-4396 on Windows allow local attackers to execute arbitrary code and conduct DLL hijacking attacks via a Trojan horse (1) shfolder.dll, (2) ntmarta.dll, (3) secur32.dll or (4) dwmapi.dll file in the current working directory.
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 Synology Cloud Station Backup installer for Windows versions prior to 4.2.5-4396 contains multiple untrusted search path vulnerabilities allowing DLL hijacking. The installer loads shfolder.dll, ntmarta.dll, secur32.dll, and dwmapi.dll from the current working directory without validating the DLL path, enabling local attackers to place Trojan horse DLLs to achieve arbitrary code execution.
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<= 4.2.4-4393CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/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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Confirm Synology Cloud Station Backup installation existsCheck for the presence of Synology Cloud Station Backup in the Windows registry under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall or look for the installation directory under C:\Program Files\Synology or C:\Program Files (x86)\SynologyAffected if The software is not found on the system at all, then the check does not apply
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Locate the installed version informationOpen the Windows registry key HKLM\SOFTWARE\Synology\CloudStation or check the version.rc file in the installation directory, or right-click the installed CloudStation.exe file and view Properties > Details for the File VersionAffected if Unable to locate any version information for the installed product
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Compare installed version against vulnerable rangeExtract the exact version number from step 2 and compare it numerically or textually to 4.2.4-4393. The vulnerable versions are any build numbers less than or equal to 4393Affected if The installed version is 4.2.4-4393 or any earlier version (such as 4.2.3-xxxx, 4.2.2-xxxx, etc.)
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Identify if the original installer file is still presentSearch for any CloudStation Backup installer files (CloudStationBackup.exe, CloudStationBackup-Setup.exe, or similar) in user-accessible locations such as Downloads folders, desktop, or temp directoriesAffected if The original installer executable exists on the system in a directory writable by other users (indicating potential for DLL hijacking if run)
If Synology Cloud Station Backup is installed with a version build number of 4393 or lower, the installer contains the DLL hijacking vulnerability.
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 dataUpgrade Synology Cloud Station Backup to version 4.2.5-4396 or later to eliminate the vulnerable code path. As a compensating control, ensure the installer is run from a directory where untrusted users cannot write files.
- Consultation2.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2017-11157 — 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-2017-11157 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
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