CyberSecBulletin
CVE-2023-28724NVD status: Analyzed

NGINX Instance Manager: Incorrect Default Permissions

Published Updated By the CyberSecBulletin desk

CVE-2023-28724 is a high-severity incorrect default permissions vulnerability in NGINX Instance Manager from F5, 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. The record lists version 2.9.0 as the first without the flaw, so updating NGINX Instance Manager to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.17% 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 NGINX Instance Manager to 2.9.0 or a later version.
  2. Update NGINX API Connectivity Manager to 1.5.0 or a later version.
  3. Update NGINX Security Monitoring to 1.3.0 or a later version.
  4. Read the advisory on my.f5.com for workarounds and exact fixed builds.

Affected products and versions

VendorProductAffected versionsFixed in
F5NGINX Instance Manager2.0.0 up to, but not including, 2.9.0; 1.0.0 and later2.9.0
F5NGINX API Connectivity Manager1.0.0 up to, but not including, 1.5.01.5.0
F5NGINX Security Monitoring1.0.0 up to, but not including, 1.3.01.3.0

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
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.1HighCNA (f5.com)
CVSS 3.17.1HighNVD

Official description

NGINX Management Suite default file permissions are set such that an authenticated attacker may be able to modify sensitive files on NGINX Instance Manager and NGINX API Connectivity Manager. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

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

The underlying weakness: Incorrect Default Permissions

During installation, installed file permissions are set to allow anyone to modify those files.

How developers prevent this class of flaw

  • The architecture needs to access and modification attributes for files to only those users who actually require those actions.
  • Compartmentalize the system to have safe areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.

More Incorrect Default Permissions vulnerabilities (CWE-276)

Timeline

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

References

Third-party and government advisories

Other vulnerabilities in NGINX Instance Manager

All NGINX Instance Manager vulnerabilities

Recent Incorrect Default Permissions vulnerabilities

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