CVE-2018-10926

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Description

A flaw was found in RPC request using gfs3_mknod_req supported by glusterfs server. An authenticated attacker could use this flaw to write files to an arbitrary location via path traversal and execute arbitrary code on a glusterfs server node.

A flaw was found in RPC request using gfs3_mknod_req supported by glusterfs server. An authenticated attacker could use this flaw to write files to an arbitrary location via path traversal and execute arbitrary code on a glusterfs server node.

Statement

This issue did not affect Red Hat Enterprise Linux 6 and 7 as the flaw is present in glusterfs-server, which is not shipped there. This flaw affects glusterfs versions included in Red Hat Virtualization 4 Hypervisor. However, in recommended configurations, the vulnerability is only exposed to hypervisor administrators and can not be exploited from virtual machines or other hosts on the network. For Red Hat Virtualization, Product Security has rated this flaw as Moderate. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.

This issue did not affect Red Hat Enterprise Linux 6 and 7 as the flaw is present in glusterfs-server, which is not shipped there.

This flaw affects glusterfs versions included in Red Hat Virtualization 4 Hypervisor. However, in recommended configurations, the vulnerability is only exposed to hypervisor administrators and can not be exploited from virtual machines or other hosts on the network. For Red Hat Virtualization, Product Security has rated this flaw as Moderate. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.

Mitigation

To limit exposure of gluster server nodes :

1. gluster server should be on LAN and not reachable from public networks.
2. Use gluster auth.allow and auth.reject.
3. Use TLS certificates to authenticate gluster clients.

caveat: This does not protect from attacks by authenticated gluster clients.

Additional information

  • Bugzilla 1613143: glusterfs: Device files can be created in arbitrary locations
  • CWE-20: Improper Input Validation
  • FAQ: Frequently asked questions about CVE-2018-10926

Common Vulnerability Scoring System (CVSS) Score Details

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 HatNVD

CVSS v3 Base Score

8.1

8.8

Attack Vector

Network

Network

Attack Complexity

Low

Low

Privileges Required

Low

Low

User Interaction

None

None

Scope

Unchanged

Unchanged

Confidentiality Impact

High

High

Integrity Impact

High

High

Availability Impact

None

High

CVSS v3 Vector

Red Hat: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

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

Understanding the Weakness (CWE)

CWE-20

Availability

Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory)

An attacker could provide unexpected values and cause a program crash or excessive consumption of resources, such as memory and CPU.

Confidentiality

Technical Impact: Read Memory; Read Files or Directories

An attacker could read confidential data if they are able to control resource references.

Integrity,Confidentiality,Availability

Technical Impact: Modify Memory; Execute Unauthorized Code or Commands

An attacker could use malicious input to modify data or possibly alter control flow in unexpected ways, including arbitrary command execution.

Acknowledgements

Red Hat would like to thank Michael Hanselmann (hansmi.ch) for reporting this issue.

Frequently Asked Questions

Why is Red Hat's CVSS v3 score or Impact different from other vendors?

My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?

What can I do if my product is listed as "Will not fix"?

What can I do if my product is listed as "Fix deferred"?

What is a mitigation?

I have a Red Hat product but it is not in the above list, is it affected?

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