CVE-2019-18422 Information

Description

An issue was discovered in Xen through 4.12.x allowing ARM guest OS users to cause a denial of service or gain privileges by leveraging the erroneous enabling of interrupts. Interrupts are unconditionally unmasked in exception handlers. When an exception occurs on an ARM system which is handled without changing processor level some interrupts are unconditionally enabled during exception entry. So exceptions which occur when interrupts are masked will effectively unmask the interrupts. A malicious guest might contrive to arrange for critical Xen code to run with interrupts erroneously enabled. This could lead to data corruption denial of service or possibly even privilege escalation. However a precise attack technique has not been identified.

CVSS Vector

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

Reference

http://www.openwall.com/lists/oss-security/2019/10/31/5 http://xenbits.xen.org/xsa/advisory-303.html https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2BQKX7M2RHCWDBKNPX4KEBI3MJIH6AYZ/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/I5WWPW4BSZDDW7VHU427XTVXV7ROOFFW/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/IZYATWNUGHRBG6I3TC24YHP5Y3J7I6KH/ https://seclists.org/bugtraq/2020/Jan/21 https://www.debian.org/security/2020/dsa-4602

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

8.8