CVE Vulnerabilities

CVE-2018-10906

Improper Authorization

Published: Jul 24, 2018 | Modified: Nov 21, 2024
CVSS 3.x
7.8
HIGH
Source:
NVD
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
4.6 MEDIUM
AV:L/AC:L/Au:N/C:P/I:P/A:P
RedHat/V2
RedHat/V3
5.3 MODERATE
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
Ubuntu
LOW

In fuse before versions 2.9.8 and 3.x before 3.2.5, fusermount is vulnerable to a restriction bypass when SELinux is active. This allows non-root users to mount a FUSE file system with the allow_other mount option regardless of whether user_allow_other is set in the fuse configuration. An attacker may use this flaw to mount a FUSE file system, accessible by other users, and trick them into accessing files on that file system, possibly causing Denial of Service or other unspecified effects.

Weakness

The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.

Affected Software

Name Vendor Start Version End Version
Debian_linux Debian 8.0 (including) 8.0 (including)
Debian_linux Debian 9.0 (including) 9.0 (including)
Red Hat Enterprise Linux 7 RedHat fuse-0:2.9.2-11.el7 *
Fuse Ubuntu bionic *
Fuse Ubuntu cosmic *
Fuse Ubuntu disco *
Fuse Ubuntu eoan *
Fuse Ubuntu esm-infra/bionic *
Fuse Ubuntu esm-infra/xenial *
Fuse Ubuntu precise/esm *
Fuse Ubuntu trusty *
Fuse Ubuntu trusty/esm *
Fuse Ubuntu upstream *
Fuse Ubuntu xenial *
Fuse3 Ubuntu disco *
Fuse3 Ubuntu eoan *
Fuse3 Ubuntu upstream *

Extended Description

Assuming a user with a given identity, authorization is the process of determining whether that user can access a given resource, based on the user’s privileges and any permissions or other access-control specifications that apply to the resource. When access control checks are not applied consistently - or not at all - users are able to access data or perform actions that they should not be allowed to perform. This can lead to a wide range of problems, including information exposures, denial of service, and arbitrary code execution.

Potential Mitigations

  • Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries.
  • Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
  • Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
  • For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
  • For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page.
  • One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.

References