#VU22997 Permissions, Privileges, and Access Controls in Xen - CVE-2019-19579

Vulnerability identifier: #VU22997

Vulnerability risk: Low

CVSSv4.0: 4.8 [CVSS:4.0/AV:A/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2019-19579

CWE-ID: CWE-264

Exploitation vector: Local network

Exploit availability: No

Vulnerable software:
Xen
Server applications / Virtualization software

Vendor: Xen Project

Description

The vulnerability allows a remote attacker to escalate privileges on the system.

The vulnerability exists due to an error within the PCI device assignment process that allows usage of alternative methods in Xen. A remote attacker with access to the guest OS and a physical device can gain write data into memory on the host operating system.

Successful exploitation of the vulnerability may allow a remote attacker to escalate privileges on the host operating system.

Mitigation

Apply the following patches:

xsa306.patch           xen-unstable
xsa306-4.12.patch      Xen 4.12.x
xsa306-4.11.patch      Xen 4.11.x, Xen 4.10.x
xsa306-4.9.patch       Xen 4.9.x, Xen 4.8.x

$ sha256sum xsa306*
07468dcdfbe34b794fd0618bce7d6d1edb6b10b234dccf1e5dd1f1120a0affe7  xsa306.meta
3534ec46f03bb8dac3011e0e3739fc75400559078e4361bbe5385d97b7892650  xsa306.patch
426e32bfa7d7787fe6778685e623966f8762857f7920443a0ca73347df9d6624  xsa306-4.9.patch
b00e58c9f96b0ff654dfd4904c675a54356148af718eb9b2adca0253b900dfc1  xsa306-4.11.patch
69857d08969903452fbf009905a145e06a5aef9966e969de9fbb22e62c557ffd  xsa306-4.12.patch

Vulnerable software versions

Xen: 4.8.0 - 4.12.1

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External links
https://xenbits.xen.org/xsa/advisory-306.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the local network (LAN).

Is there known malware, which exploits this vulnerability?

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