VMware Multiple Products Privilege Escalation
CVE-2020-3950 is a high-severity improper privilege management vulnerability in VMware Fusion, VMware Remote Console for Mac and Horizon Client for Mac, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. CISA added it to the Known Exploited Vulnerabilities catalogue on November 3, 2021, which means attacks have been observed in the wild.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Fusion to 11.5.2 or a later version.
- Update Horizon Client to 5.4.0 or a later version.
- Update Remote Console to 11.0.1 or a later version.
- CISA's required action: Apply updates per vendor instructions.
- Read the advisory on vmware.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| VMware Fusion, VMware Remote Console for Mac and Horizon Client for Mac | VMware Fusion, VMware Remote Console for Mac and Horizon Client for Mac | Not specified in the record | Not stated |
| VMware | Fusion | 11.0.0 up to, but not including, 11.5.2 | 11.5.2 |
| VMware | Horizon Client | 5.0.0 up to, but not including, 5.4.0 | 5.4.0 |
| VMware | Remote Console | 11.0.0 up to, but not including, 11.0.1 | 11.0.1 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | NVD |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
| CVSS 2.0 | 7.2 | High | NVD |
Official description
VMware Fusion (11.x before 11.5.2), VMware Remote Console for Mac (11.x and prior before 11.0.1) and Horizon Client for Mac (5.x and prior before 5.4.0) contain a privilege escalation vulnerability due to improper use of setuid binaries. Successful exploitation of this issue may allow attackers with normal user privileges to escalate their privileges to root on the system where Fusion, VMRC or Horizon Client is installed.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Privilege Management
The product does not properly assign, modify, track, or check privileges for an actor, creating an unintended sphere of control for that actor.
How developers prevent this class of flaw
- Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
- Follow the principle of least privilege when assigning access rights to entities in a software system.
- Consider following the principle of separation of privilege. Require multiple conditions to be met before permitting access to a system resource.
More Improper Privilege Management vulnerabilities (CWE-269)
Timeline
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-3950US Government Resource
Technical write-ups (may include proof of concept)
- packetstormsecurity.com/files/156843/VMware-Fusion-11.5.2-Privilege-Escalation.htmlExploit, Third Party Advisory, VDB Entry
- packetstormsecurity.com/files/157079/VMware-Fusion-USB-Arbitrator-Setuid-Privilege-Escalation.htmlExploit, Third Party Advisory, VDB Entry
Recent Improper Privilege Management vulnerabilities
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Microsoft Windows Privilege Escalation Exploited
- 9.8 Critical severity
- 7.8 High severity
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