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CVE-2017-7471: Qemu: Incorrect Permission Assignment for Critical Resource

CVE-2017-7471 is rated critical with a CVSS v3.1 base score of 9.0 and affects Qemu. Per its scoring, it can be exploited without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available.

Vulnerability description

Quick Emulator (Qemu) built with the VirtFS, host directory sharing via Plan 9 File System (9pfs) support, is vulnerable to an improper access control issue. It could occur while accessing files on a shared host directory. A privileged user inside guest could use this flaw to access host file system beyond the shared folder and potentially escalating their privileges on a host.

Severity breakdown

CVSS v3.1 9.0: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

  • Attack vector: Adjacent. The attacker must be on the same shared network segment.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: Low. A basic user account is enough.
  • User interaction: None. No action from any user is needed.
  • Scope: Changed. Impact reaches beyond the vulnerable component to other resources.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-732: Incorrect Permission Assignment for Critical Resource

The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.

Affected products

  • Qemu: up to and including 2.8.1.1; 2.9.0 rc0; 2.9.0 rc1; 2.9.0 rc2; 2.9.0 rc3; 2.9.0 rc4

References