#VU85928 Permissions, Privileges, and Access Controls in Xen - CVE-2023-46840

Vulnerability identifier: #VU85928

Vulnerability risk: Medium

CVSSv4.0: [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:U/U:Green]

CVE-ID: CVE-2023-46840

CWE-ID: CWE-264

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Xen
Server applications / Virtualization software

Vendor: Xen Project

Description

The vulnerability allows a malicious guest to bypass implemented security restrictions.

The vulnerability exists due to incorrect placement of a preprocessor directive in source code, which results in a logic error when support for HVM guests is compiled out of Xen and CONFIG_HVM is disabled at Xen's build time. When a device is removed from a domain, it is not properly quarantined and retains its access to the domain to which it was previously assigned. An attacker with control over a malicious guest can retain access to the domain after it has been removed from it.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Xen: 4.17 - 4.18.0

---

External links
http://xenbits.xen.org/xsa/advisory-450.html

---

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.