Security readout for executives and security teams
Plain-English summary
This flaw lets a logged-in user bypass directory permission checks in Synology Universal Search’s Highlight Preview feature. The main business risk is unauthorized viewing of restricted file content or metadata on affected Synology systems. It is not described as enabling data modification or service disruption.
Executive priority
Treat this as a moderate confidentiality issue. Prioritize patching where Synology devices store sensitive shared files or support many non-admin users. It is less urgent than unauthenticated remote code execution, but still important for internal data exposure risk.
Technical view
CVE-2017-16773 is a CWE-285 improper authorization issue in Synology Universal Search before 1.0.5-0135. Remote authenticated users can bypass permission checks for POSIX-mode directories through Highlight Preview. CVSS 3.0 is 6.5, with network access, low privileges, no user interaction, and high confidentiality impact.
Likely exposure
Exposure is likely limited to Synology systems running Universal Search versions before 1.0.5-0135 where authenticated users can access the service and restricted directories use POSIX mode.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. Exploitation requires authentication, but a low-privilege account may be enough to expose data the user should not be able to preview.
Researcher notes
Key conditions are Universal Search before 1.0.5-0135, authenticated remote access, Highlight Preview, and POSIX-mode directories. Evidence in the bundle supports confidentiality impact only. No public exploit status or detailed workaround is provided beyond vendor advisory and version boundary.
Mitigation direction
- Upgrade Synology Universal Search to 1.0.5-0135 or later.
- Review Synology advisory SA-18:27 for vendor-specific remediation details.
- Restrict access to Synology services to trusted users and networks.
- Review permissions on sensitive POSIX-mode directories.
Validation and detection
- Inventory Synology systems running Universal Search and record package versions.
- Confirm no affected system is running a version before 1.0.5-0135.
- Review restricted directories that rely on POSIX permissions.
- Verify low-privilege users cannot preview restricted directory content.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CWE-285: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2017-16773 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.5 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N2.83.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
6.5MediumVector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://www.synology.com/en-global/support/security/Synology_SA_18_27CVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Authorization
Improper Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.