Zoom for Windows Client: Improper Verification of Cryptographic Signature
CVE-2023-34120 is a high-severity improper verification of cryptographic signature vulnerability in Zoom for Windows Client from Zoom Video Communications, 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. Affected Zoom for Windows Client versions: before 5.14.0. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.13% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Virtual Desktop Infrastructure to 5.14.0 or a later version.
- Read the advisory on explore.zoom.us for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Zoom Video Communications | Zoom for Windows Client | before 5.14.0 | Not stated |
| Zoom Video Communications | Zoom Rooms Client for Windows | before 5.14.0 | Not stated |
| Zoom Video Communications | Zoom VDI for Windows Meeting Clients | before 5.14.0 | Not stated |
| Zoom | Virtual Desktop Infrastructure | before 5.14.0 | 5.14.0 |
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 | 8.7 | High | CNA (zoom.us) |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
Improper privilege management in Zoom for Windows, Zoom Rooms for Windows, and Zoom VDI for Windows clients before 5.14.0 may allow an authenticated user to potentially enable an escalation of privilege via local access. Users may potentially utilize higher level system privileges maintained by the Zoom client to spawn processes with escalated privileges.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Verification of Cryptographic Signature
The product does not verify, or incorrectly verifies, the cryptographic signature for data.
More Improper Verification of Cryptographic Signature vulnerabilities (CWE-347)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in Zoom for Windows Client
- 7.7 High severity
Recent Improper Verification of Cryptographic Signature vulnerabilities
- 8.8 High severity
- 9.1 Critical severity
- 7.8 High severity
- 7.5 High severity
- 9.8 Critical severity
- 7.8 High severity
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