CVE-2020-12510
If the directory does not exist it and further subdirectories are created with permissions which allow every local user to modify the content.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.88%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
The default installation path of the TwinCAT XAR 3.1 software in all versions is underneath C:\TwinCAT. If the directory does not exist it and further subdirectories are created with permissions which allow every local user to modify the content. The default installation registers TcSysUI.exe for automatic execution upon log in of a user. If a less privileged user has a local account he or she can replace TcSysUI.exe. It will be executed automatically by another user during login. This is also true for users with administrative access. Consequently, a less privileged user can trick a higher privileged user into executing code he or she modified this way. By default Beckhoff’s IPCs are shipped with TwinCAT software installed this way and with just a single local user configured. Thus the vulnerability exists if further less privileged users have been added.
- CVSS 3.1
- 7.3 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
- EPSS
- 0.88% probability · 57th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-276
- Affected
- beckhoff/twincat extended automation runtime
- Source
- info@cert.vde.com
References
- https://cert.vde.com/en-us/advisories/vde-2020-037Third Party Advisory
- https://cert.vde.com/en-us/advisories/vde-2020-037Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.