Quantum Secular Labs / Blog / Advisories

CVE-2017-2620: Qemu: Code execution

CVE-2017-2620 is rated critical with a CVSS v3.0 base score of 9.9 and affects Qemu, along with 9 other products in NVD’s configuration data. Per its scoring, it can be exploited over the network, without any user interaction. The scored impact on confidentiality, integrity and availability is the highest available.

Vulnerability description

Quick emulator (QEMU) before 2.8 built with the Cirrus CLGD 54xx VGA Emulator support is vulnerable to an out-of-bounds access issue. The issue could occur while copying VGA data in cirrus_bitblt_cputovideo. A privileged user inside guest could use this flaw to crash the QEMU process OR potentially execute arbitrary code on host with privileges of the QEMU process.

Severity breakdown

CVSS v3.0 9.9: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • 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-787: Out-of-bounds Write

The product writes data past the end, or before the beginning, of the intended buffer.

CWE-125: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

Affected products

  • Qemu: before 2.8.0
  • Citrix Xenserver: 6.0.2; 6.2.0 sp1; 6.5 sp1; 7.0; 7.1
  • Red Hat Openstack: 5.0; 6.0; 7.0; 8; 9; 10
  • Debian Linux: 7.0
  • Red Hat Enterprise Linux Desktop: 6.0; 7.0
  • Red Hat Enterprise Linux Server: 6.0; 7.0
  • Red Hat Enterprise Linux Server Aus: 7.3; 7.4
  • Red Hat Enterprise Linux Server Eus: 7.3; 7.4; 7.5
  • Red Hat Enterprise Linux Workstation: 6.0; 7.0
  • Xen: up to and including 4.7.1; 4.7.1 r1; 4.7.1 r2; 4.7.1 r3; 4.7.1 r4; 4.7.1 r5; 4.7.1 r6; 4.7.1 r7

References