Resource management error in xen (Alpine package)

1) Resource management error

EUVDB-ID: #VU22538

Risk: Medium

CVSSv3.1: 5.4 [CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2019-18423

CWE-ID: CWE-399 - Resource Management Errors

Exploit availability: No

Description

The vulnerability allows a remote user to perform a denial of service (DoS) attack.

The vulnerability exists due to the p2m_get_root_pointer() function in Xen ignores the unused top bits of a guest physical frame. A remote administrator of a guest operating system can use a specially crafted hypercall XENMEM_add_to_physmap{, _batch} followed by an access to an address (via hypercall or direct access) that passes the sanity check but cause p2m_get_root_pointer() to return NULL. As a result, the attacker can crash the hypervisor from the guest operating system.

Mitigation

Install update from vendor's website.

Vulnerable software versions

xen (Alpine package): 4.8.2-r0 - 4.10.4-r0

External links

http://git.alpinelinux.org/aports/commit/?id=b56efe8db5679b569767cee09b45ce5cd04b942d
http://git.alpinelinux.org/aports/commit/?id=7704a01fec21129dc2f13feb032fb39d8b6a9cb2
http://git.alpinelinux.org/aports/commit/?id=168f974f4f9941c940b1b4a27d1167175018ad92
http://git.alpinelinux.org/aports/commit/?id=1a7ae75cb9ed94f62f9859f8a07a0bc1c5021604
http://git.alpinelinux.org/aports/commit/?id=d9cf7666f5f3aa90dbce9f04bdc7d975284cc530

Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

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