CyberSecBulletin
CVE-2023-50916NVD status: Modified

Device Manager: Improper Limitation of a Pathname to a Restricted Directory

CVE-2023-50916 is a high-severity improper limitation of a pathname to a restricted directory vulnerability in Device Manager from Kyocera, with a CVSS 3.1 base score of 7.2 out of 10. It can be exploited remotely over the network by an attacker with administrator privileges, without any action from a user. The record lists version 3.1.1213.0 as the first without the flaw, so updating Device Manager to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 4.63% chance of exploitation within 30 days, which is in the top 8.14% of all scored CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Device Manager to 3.1.1213.0 or a later version.
  2. Read the advisory on kyoceradocumentsolutions.us for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
KyoceraDevice Managerbefore 3.1.1213.03.1.1213.0

Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
HighAdministrator-level access is required first.
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:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.2HighNVD
CVSS 3.17.2HighCISA (ADP)

Official description

Kyocera Device Manager before 3.1.1213.0 allows NTLM credential exposure during UNC path authentication via a crafted change from a local path to a UNC path. It allows administrators to configure the backup location of the database used by the application. Attempting to change this location to a UNC path via the GUI is rejected due to the use of a \ (backslash) character, which is supposed to be disallowed in a pathname. Intercepting and modifying this request via a proxy, or sending the request directly to the application endpoint, allows UNC paths to be set for the backup location. Once such a location is set, Kyocera Device Manager attempts to confirm access and will try to authenticate to the UNC path; depending on the configuration of the environment, this may authenticate to the UNC with Windows NTLM hashes. This could allow NTLM credential relaying or cracking attacks.

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

The underlying weakness: Improper Limitation of a Pathname to a Restricted Directory

The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

How developers prevent this class of flaw

  • 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.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
  • Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth.

More Improper Limitation of a Pathname to a Restricted Directory vulnerabilities (CWE-22)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Technical write-ups (may include proof of concept)

Recent Improper Limitation of a Pathname to a Restricted Directory vulnerabilities

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