CVE-2021-20208
Description
A flaw was found in cifs-utils. A user when mounting a krb5 CIFS file system from within a container can use Kerberos credentials of the host. The highest threat from this vulnerability is to data confidentiality and integrity.
Statement
This flaw is rated as having Moderate impact because of the need to have elevated privileges and limited possibilities of the attack: an attacker will not get actual credentials cache accessed by themselves, but might cause an authentication attempt to an SMB server and may be succeed in file access.
Mitigation
DFS and multiuser mounts can be disabled in the container SMB mounts options i.e. adding 'nodfs' and removing 'multiuser' (if present).
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.1 | 6.1 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | Required | Required | N/A |
| Scope | Changed | Changed | N/A |
| Confidentiality | Low | Low | N/A |
| Integrity Impact | High | High | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:L/I:H/A:N
NVD: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:L/I:H/A:N
Understanding the Weakness (CWE)
Access Control
Technical Impact: Gain Privileges or Assume Identity
A user can access restricted functionality and/or sensitive information that may include administrative functionality and user accounts.
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