CyberSecBulletin
CVE-2023-28603NVD status: Modified

Zoom VDI Windows Meeting Client: External Control of File Name or Path

CVE-2023-28603 is a high-severity external control of file name or path vulnerability in Zoom VDI Windows Meeting Client from Zoom Video Communications, with a CVSS 3.1 base score of 7.1 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 VDI Windows Meeting 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 0.16% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Virtual Desktop Infrastructure to 5.14.0 or a later version.
  2. Read the advisory on explore.zoom.us for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
Zoom Video CommunicationsZoom VDI Windows Meeting Clientbefore 5.14.0Not stated
ZoomVirtual Desktop Infrastructurebefore 5.14.05.14.0

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
NoneNo data is disclosed.
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:N/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.7HighCNA (zoom.us)
CVSS 3.17.1HighNVD

Official description

Zoom VDI client installer prior to 5.14.0 contains an improper access control vulnerability. A malicious user may potentially delete local files without proper permissions.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: External Control of File Name or Path

The product allows user input to control or influence paths or file names that are used in filesystem operations.

How developers prevent this class of flaw

  • When the set of filenames is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames, and reject all other inputs. For example, ID 1 could map to inbox.txt and ID 2 could map to profile.txt. Features such as the ESAPI AccessReferenceMap provide this capability.
  • Run your code in a jail or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict all access to files within a particular directory. Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection. This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise. Be careful to avoid CWE-243 and other weaknesses related to jails.
  • For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.

More External Control of File Name or Path vulnerabilities (CWE-73)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent External Control of File Name or Path vulnerabilities

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