RCE in Xen
CVE-2019-18424
An issue was discovered in Xen through 4.12.x allowing attackers to gain host OS privileges via DMA in a situation where an untrusted domain has access to a physical device. This occurs because passed through PCI devices may corrupt host memory after deassignment. When a PCI device is assigned to an untrusted domain, it is possible for that domain to program the device to DMA to an arbitrary address. The IOMMU is used to protect the host from malicious DMA by making sure that the device addresses can only target memory assigned to the guest. However, when the guest domain is torn down, or the device is deassigned, the device is assigned back to dom0, thus allowing any in-flight DMA to potentially target critical host data. An untrusted domain with access to a physical device can DMA into host memory, leading to privilege escalation. Only systems where guests are given direct access to physical devices capable of DMA (PCI pass-through) are vulnerable. Systems which do not use PCI pass-through are not vulnerable.
Vulnerability class: Command Injection (OS Command Injection)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.8 (Medium). Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.005 (40.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 40th percentile — 40.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000
Affected products
- Xen
- Debian Linux — versions 9.0, 10.0
- Fedoraproject Fedora — versions 29, 30, 31
- openSUSE Leap — versions 15.0
Weakness classification (CWE)
References
- xenbits.xen.org/xsa/advisory-302.html (Patch, Mitigation, Vendor Advisory)
- www.openwall.com/lists/oss-security/2019/10/31/6 (mailing-list, Mailing List, Third Party Advisory, Mitigation)
- lists.opensuse.org/opensuse-security-announce/2019-11/msg00037.html (vendor-advisory, Mailing List, Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- www.debian.org/security/2020/dsa-4602 (vendor-advisory, Third Party Advisory)
- seclists.org/bugtraq/2020/Jan/21 (mailing-list, Mailing List, Third Party Advisory)
- security.gentoo.org/glsa/202003-56 (vendor-advisory, Third Party Advisory)
Frequently asked questions
- What is CVE-2019-18424?
- CVE-2019-18424 is a medium-severity vulnerability in Xen, classified under OS Command Injection. CVSS score: 6.8/10. Published 2019-10-31.
- How severe is CVE-2019-18424?
- Medium severity. CVSS v3 base score is 6.8 out of 10.