CVE-2019-10161
Description
It was discovered that libvirtd would permit read-only clients to use the virDomainSaveImageGetXMLDesc() API, specifying an arbitrary path which would be accessed with the permissions of the libvirtd process. An attacker with access to the libvirtd socket could use this to probe the existence of arbitrary files, cause denial of service or cause libvirtd to execute arbitrary programs.
Statement
- This vulnerability requires access to the libvirt socket, normally in /var/run/libvirt/libvirt_sock_ro. Typically in hypervisor environments, local user accounts are not supported so no untrusted users should be able to access this socket.
- Red Hat Gluster Storage 3 is not affected by this vulnerability as libvirtd daemon is not shipped in Gluster.
- On Red Hat Enterprise Linux 6, the impact of this vulnerability is limited to denial of service or disclosing the existence of arbitrary files. Privilege escalation is not possible. For RHEL6, this CVE is rated as Moderate severity with 7.3/CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:H
Mitigation
The Unix permissions of libvirt's read-only socket can be made more restrictive than the default (0777) by editing `/etc/libvirt/libvirtd.conf`. The settings `unix_sock_group = libvirt` and `unix_sock_ro_perms = 0770` will restrict access to only members of `libvirt`, who already have management access to virtual machines.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.8 | 7.8 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Changed | Unchanged | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | High | High | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Other
Technical Impact: Varies by Context
Acknowledgements
Red Hat would like to thank Matthias Gerstner (SUSE) for reporting this issue.
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