Security readout for executives and security teams
Plain-English summary
TwinCAT XAR 3.1 can be installed with weak permissions under C:\TwinCAT. A local low-privileged user could alter files that run automatically when another user logs in, potentially gaining that user’s privileges. This matters most on Beckhoff IPCs where extra non-admin local users were added.
Executive priority
Treat this as high priority for OT workstations or IPCs with multiple local users. It is not an internet-facing remote flaw, but successful abuse could give an insider or compromised local account full confidentiality, integrity, and availability impact on affected systems.
Technical view
CVE-2020-12510 is a CWE-276 improper default permissions issue in Beckhoff TwinCAT XAR 3.1. The default install path and subdirectories may be writable by every local user, while TcSysUI.exe is registered for automatic execution at login. Successful abuse requires local low-privileged access and a higher-privileged user login.
Likely exposure
Exposure is likely limited to systems running TwinCAT XAR 3.1, especially Beckhoff IPCs with additional less-privileged local users. The bundle states default Beckhoff IPCs ship with one local user, so the issue exists when further low-privileged users have been added.
Exploitation context
The CVE is not listed as CISA KEV in the provided bundle, and no source here reports active exploitation. Abuse requires local account access and user interaction: another user, potentially an administrator, must log in and trigger the modified autostart executable.
Researcher notes
The core issue is weak default ACLs combined with login autostart execution. CVSS 3.1 is 7.3 with AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H. Evidence in the bundle does not identify a patch version, exploit tooling, or active exploitation.
Mitigation direction
- Review Beckhoff/VDE advisory VDE-2020-037 for official remediation guidance.
- Inventory TwinCAT XAR 3.1 installations on Beckhoff IPCs and Windows hosts.
- Remove unnecessary low-privileged local accounts from affected IPCs.
- Review and restrict C:\TwinCAT permissions according to vendor guidance.
- Monitor for unexpected changes to TcSysUI.exe and TwinCAT installation files.
Validation and detection
- Confirm whether TwinCAT XAR 3.1 is installed under C:\TwinCAT.
- Check whether non-admin local users exist on each affected host.
- Verify whether C:\TwinCAT and subdirectories are writable by standard users.
- Confirm TcSysUI.exe is registered for automatic execution at user login.
- Review file integrity history for TcSysUI.exe and TwinCAT binaries.
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-2020-12510 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
- 7.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/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:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H1.35.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.3HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://cert.vde.com/en-us/advisories/vde-2020-037CVE 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.
Incorrect Default Permissions
Incorrect Default Permissions represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.