CVE Vulnerabilities

CVE-2021-35938

Improper Link Resolution Before File Access ('Link Following')

Published: Aug 25, 2022 | Modified: Nov 29, 2022
CVSS 3.x
6.7
MEDIUM
Source:
NVD
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
RedHat/V2
RedHat/V3
6.5 MODERATE
CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H
Ubuntu
MEDIUM

A symbolic link issue was found in rpm. It occurs when rpm sets the desired permissions and credentials after installing a file. A local unprivileged user could use this flaw to exchange the original file with a symbolic link to a security-critical file and escalate their privileges on the system. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Weakness

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Affected Software

Name Vendor Start Version End Version
Rpm Rpm * 4.18.0 (excluding)
Rpm Ubuntu bionic *
Rpm Ubuntu groovy *
Rpm Ubuntu hirsute *
Rpm Ubuntu impish *
Rpm Ubuntu kinetic *
Rpm Ubuntu lunar *
Rpm Ubuntu mantic *
Rpm Ubuntu trusty *
Rpm Ubuntu trusty/esm *
Rpm Ubuntu xenial *
Red Hat Enterprise Linux 8 RedHat rpm-0:4.14.3-28.el8_9 *
Red Hat Enterprise Linux 8 RedHat rpm-0:4.14.3-28.el8_9 *
Red Hat Enterprise Linux 8.6 Extended Update Support RedHat rpm-0:4.14.3-26.el8_6 *
Red Hat Enterprise Linux 8.8 Extended Update Support RedHat rpm-0:4.14.3-28.el8_8 *
Red Hat Enterprise Linux 9 RedHat rpm-0:4.16.1.3-27.el9_3 *
Red Hat Enterprise Linux 9 RedHat rpm-0:4.16.1.3-27.el9_3 *
Red Hat Enterprise Linux 9.0 Extended Update Support RedHat rpm-0:4.16.1.3-14.el9_0.1 *
Red Hat Enterprise Linux 9.2 Extended Update Support RedHat rpm-0:4.16.1.3-24.el9_2 *
Red Hat OpenShift Container Platform 4.13 RedHat openshift4-wincw/windows-machine-config-operator-bundle:v8.1.2-13 *
Red Hat OpenShift Container Platform 4.13 RedHat openshift4-wincw/windows-machine-config-rhel9-operator:8.1.2-13 *
RHODF-4.15-RHEL-9 RedHat odf4/cephcsi-rhel9:v4.15.0-37 *
RHODF-4.15-RHEL-9 RedHat odf4/mcg-core-rhel9:v4.15.0-68 *
RHODF-4.15-RHEL-9 RedHat odf4/mcg-operator-bundle:v4.15.0-158 *
RHODF-4.15-RHEL-9 RedHat odf4/mcg-rhel9-operator:v4.15.0-39 *
RHODF-4.15-RHEL-9 RedHat odf4/ocs-client-console-rhel9:v4.15.0-58 *
RHODF-4.15-RHEL-9 RedHat odf4/ocs-client-operator-bundle:v4.15.0-158 *
RHODF-4.15-RHEL-9 RedHat odf4/ocs-client-rhel9-operator:v4.15.0-13 *
RHODF-4.15-RHEL-9 RedHat odf4/ocs-metrics-exporter-rhel9:v4.15.0-81 *
RHODF-4.15-RHEL-9 RedHat odf4/ocs-operator-bundle:v4.15.0-158 *
RHODF-4.15-RHEL-9 RedHat odf4/ocs-rhel9-operator:v4.15.0-79 *
RHODF-4.15-RHEL-9 RedHat odf4/odf-cli-rhel9:v4.15.0-22 *
RHODF-4.15-RHEL-9 RedHat odf4/odf-console-rhel9:v4.15.0-57 *
RHODF-4.15-RHEL-9 RedHat odf4/odf-cosi-sidecar-rhel9:v4.15.0-6 *
RHODF-4.15-RHEL-9 RedHat odf4/odf-csi-addons-operator-bundle:v4.15.0-158 *
RHODF-4.15-RHEL-9 RedHat odf4/odf-csi-addons-rhel9-operator:v4.15.0-15 *
RHODF-4.15-RHEL-9 RedHat odf4/odf-csi-addons-sidecar-rhel9:v4.15.0-15 *
RHODF-4.15-RHEL-9 RedHat odf4/odf-multicluster-console-rhel9:v4.15.0-54 *
RHODF-4.15-RHEL-9 RedHat odf4/odf-multicluster-operator-bundle:v4.15.0-158 *
RHODF-4.15-RHEL-9 RedHat odf4/odf-multicluster-rhel9-operator:v4.15.0-10 *
RHODF-4.15-RHEL-9 RedHat odf4/odf-must-gather-rhel9:v4.15.0-26 *
RHODF-4.15-RHEL-9 RedHat odf4/odf-operator-bundle:v4.15.0-158 *
RHODF-4.15-RHEL-9 RedHat odf4/odf-rhel9-operator:v4.15.0-19 *
RHODF-4.15-RHEL-9 RedHat odf4/odr-cluster-operator-bundle:v4.15.0-158 *
RHODF-4.15-RHEL-9 RedHat odf4/odr-hub-operator-bundle:v4.15.0-158 *
RHODF-4.15-RHEL-9 RedHat odf4/odr-rhel9-operator:v4.15.0-21 *
RHODF-4.15-RHEL-9 RedHat odf4/rook-ceph-rhel9-operator:v4.15.0-103 *

Potential Mitigations

  • Follow the principle of least privilege when assigning access rights to entities in a software system.
  • Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

References