Security readout for executives and security teams
Plain-English summary
CVE-2021-40388 lets a low-privileged local attacker escalate to NT SYSTEM on a host running Advantech SQ Manager Server 1.0.6 by abusing unsafe file replacement behavior. Treat this as high urgency where the product is installed, because compromise of one local account could become full host control.
Executive priority
High priority for environments using Advantech SQ Manager Server 1.0.6. This is not a remote-entry vulnerability, but it can convert a limited local compromise into full system authority, increasing ransomware and lateral-movement risk on affected hosts.
Technical view
The vulnerability is a CWE-276 incorrect default permissions issue in Advantech SQ Manager Server 1.0.6. The CVSS 3.0 score is 8.8 with local attack vector, low complexity, low privileges required, no user interaction, changed scope, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure appears limited to systems running Advantech SQ Manager Server 1.0.6. The CVE source bundle does not provide CPEs or broader affected-version details, so asset validation should not assume other versions are affected without vendor confirmation.
Exploitation context
The source bundle describes local privilege escalation through replacement of a specially crafted file. It does not cite public active exploitation, and the CVE is not listed as KEV in the provided data. A prior local foothold or low-privileged account is required.
Researcher notes
Evidence is strong for vulnerability class, affected version, and impact, but incomplete for exploit maturity, fixed versions, and vendor remediation. Avoid assuming internet exposure; focus on local account paths, software inventory, Windows host hardening, and official advisory confirmation.
Mitigation direction
- Identify all systems running Advantech SQ Manager Server 1.0.6.
- Check Advantech and Talos guidance for fixed versions or vendor mitigations.
- Prioritize remediation on shared servers, operational hosts, and systems with untrusted local users.
- Restrict local interactive access to affected systems until remediation is confirmed.
- Monitor affected hosts for suspicious file replacement and privilege escalation activity.
Validation and detection
- Inventory installed SQ Manager Server versions across Windows endpoints and servers.
- Confirm whether any discovered instance is version 1.0.6.
- Review vendor and Talos references for official affected-version and fix details.
- Check endpoint logs for abnormal service-file changes or unexpected SYSTEM-level process activity.
- Document compensating controls if immediate vendor remediation is unavailable.
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-276: 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 lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-40388 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
- High
- CVSS
- 8.8 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
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:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H26Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
8.8HighVector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://talosintelligence.com/vulnerability_reports/TALOS-2021-1399CVE reference · x_refsource_MISC
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.
Incorrect Default Permissions
Incorrect Default Permissions represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.