SUSE SLES15 Security Update : xen (SUSE-SU-2022:3928-1)

high Nessus Plugin ID 167337



The remote SUSE host is missing one or more security updates.


The remote SUSE Linux SLES15 / SLES_SAP15 host has packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2022:3928-1 advisory.

- x86: Speculative vulnerabilities with bare (non-shim) 32-bit PV guests 32-bit x86 PV guest kernels run in ring 1. At the time when Xen was developed, this area of the i386 architecture was rarely used, which is why Xen was able to use it to implement paravirtualisation, Xen's novel approach to virtualization. In AMD64, Xen had to use a different implementation approach, so Xen does not use ring 1 to support 64-bit guests. With the focus now being on 64-bit systems, and the availability of explicit hardware support for virtualization, fixing speculation issues in ring 1 is not a priority for processor companies. Indirect Branch Restricted Speculation (IBRS) is an architectural x86 extension put together to combat speculative execution sidechannel attacks, including Spectre v2. It was retrofitted in microcode to existing CPUs. For more details on Spectre v2, see: However, IBRS does not architecturally protect ring 0 from predictions learnt in ring 1. For more details, see: speculation Similar situations may exist with other mitigations for other kinds of speculative execution attacks. The situation is quite likely to be similar for speculative execution attacks which have yet to be discovered, disclosed, or mitigated. (CVE-2021-28689)

- Linux disk/nic frontends data leaks T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Linux Block and Network PV device frontends don't zero memory regions before sharing them with the backend (CVE-2022-26365, CVE-2022-33740).
Additionally the granularity of the grant table doesn't allow sharing less than a 4K page, leading to unrelated data residing in the same 4K page as data shared with a backend being accessible by such backend (CVE-2022-33741, CVE-2022-33742). (CVE-2022-26365, CVE-2022-33740, CVE-2022-33741, CVE-2022-33742)

- P2M pool freeing may take excessively long The P2M pool backing second level address translation for guests may be of significant size. Therefore its freeing may take more time than is reasonable without intermediate preemption checks. Such checking for the need to preempt was so far missing. (CVE-2022-33746)

- lock order inversion in transitive grant copy handling As part of XSA-226 a missing cleanup call was inserted on an error handling path. While doing so, locking requirements were not paid attention to. As a result two cooperating guests granting each other transitive grants can cause locks to be acquired nested within one another, but in respectively opposite order. With suitable timing between the involved grant copy operations this may result in the locking up of a CPU. (CVE-2022-33748)

- Xenstore: Guests can crash xenstored Due to a bug in the fix of XSA-115 a malicious guest can cause xenstored to use a wrong pointer during node creation in an error path, resulting in a crash of xenstored or a memory corruption in xenstored causing further damage. Entering the error path can be controlled by the guest e.g. by exceeding the quota value of maximum nodes per domain. (CVE-2022-42309)

- Xenstore: Guests can create orphaned Xenstore nodes By creating multiple nodes inside a transaction resulting in an error, a malicious guest can create orphaned nodes in the Xenstore data base, as the cleanup after the error will not remove all nodes already created. When the transaction is committed after this situation, nodes without a valid parent can be made permanent in the data base. (CVE-2022-42310)

- Xenstore: guests can let run xenstored out of memory T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Malicious guests can cause xenstored to allocate vast amounts of memory, eventually resulting in a Denial of Service (DoS) of xenstored. There are multiple ways how guests can cause large memory allocations in xenstored: - - by issuing new requests to xenstored without reading the responses, causing the responses to be buffered in memory - - by causing large number of watch events to be generated via setting up multiple xenstore watches and then e.g. deleting many xenstore nodes below the watched path - - by creating as many nodes as allowed with the maximum allowed size and path length in as many transactions as possible - - by accessing many nodes inside a transaction (CVE-2022-42311, CVE-2022-42312, CVE-2022-42313, CVE-2022-42314, CVE-2022-42315, CVE-2022-42316, CVE-2022-42317, CVE-2022-42318)

- Xenstore: Guests can cause Xenstore to not free temporary memory When working on a request of a guest, xenstored might need to allocate quite large amounts of memory temporarily. This memory is freed only after the request has been finished completely. A request is regarded to be finished only after the guest has read the response message of the request from the ring page. Thus a guest not reading the response can cause xenstored to not free the temporary memory. This can result in memory shortages causing Denial of Service (DoS) of xenstored. (CVE-2022-42319)

- Xenstore: Guests can get access to Xenstore nodes of deleted domains Access rights of Xenstore nodes are per domid. When a domain is gone, there might be Xenstore nodes left with access rights containing the domid of the removed domain. This is normally no problem, as those access right entries will be corrected when such a node is written later. There is a small time window when a new domain is created, where the access rights of a past domain with the same domid as the new one will be regarded to be still valid, leading to the new domain being able to get access to a node which was meant to be accessible by the removed domain. For this to happen another domain needs to write the node before the newly created domain is being introduced to Xenstore by dom0. (CVE-2022-42320)

- Xenstore: Guests can crash xenstored via exhausting the stack Xenstored is using recursion for some Xenstore operations (e.g. for deleting a sub-tree of Xenstore nodes). With sufficiently deep nesting levels this can result in stack exhaustion on xenstored, leading to a crash of xenstored. (CVE-2022-42321)

- Xenstore: Cooperating guests can create arbitrary numbers of nodes T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Since the fix of XSA-322 any Xenstore node owned by a removed domain will be modified to be owned by Dom0. This will allow two malicious guests working together to create an arbitrary number of Xenstore nodes. This is possible by domain A letting domain B write into domain A's local Xenstore tree. Domain B can then create many nodes and reboot. The nodes created by domain B will now be owned by Dom0. By repeating this process over and over again an arbitrary number of nodes can be created, as Dom0's number of nodes isn't limited by Xenstore quota. (CVE-2022-42322, CVE-2022-42323)

- Xenstore: Guests can create arbitrary number of nodes via transactions T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] In case a node has been created in a transaction and it is later deleted in the same transaction, the transaction will be terminated with an error. As this error is encountered only when handling the deleted node at transaction finalization, the transaction will have been performed partially and without updating the accounting information. This will enable a malicious guest to create arbitrary number of nodes.
(CVE-2022-42325, CVE-2022-42326)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.


Update the affected packages.

See Also

Plugin Details

Severity: High

ID: 167337

File Name: suse_SU-2022-3928-1.nasl

Version: 1.6

Type: local

Agent: unix

Published: 11/13/2022

Updated: 9/8/2023

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment

Risk Information


Risk Factor: High

Score: 7.3


Risk Factor: Low

Base Score: 3.6

Temporal Score: 2.7

Vector: CVSS2#AV:L/AC:L/Au:N/C:P/I:N/A:P

CVSS Score Source: CVE-2022-33742


Risk Factor: High

Base Score: 8.8

Temporal Score: 7.7

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS Score Source: CVE-2022-42309

Vulnerability Information

CPE: p-cpe:/a:novell:suse_linux:xen, p-cpe:/a:novell:suse_linux:xen-libs, p-cpe:/a:novell:suse_linux:xen-tools, p-cpe:/a:novell:suse_linux:xen-tools-domu, p-cpe:/a:novell:suse_linux:xen-devel, cpe:/o:novell:suse_linux:15

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/SuSE/release, Host/SuSE/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 11/10/2022

Vulnerability Publication Date: 2/18/2021

Reference Information

CVE: CVE-2021-28689, CVE-2022-26365, CVE-2022-33740, CVE-2022-33741, CVE-2022-33742, CVE-2022-33746, CVE-2022-33748, CVE-2022-42309, CVE-2022-42310, CVE-2022-42311, CVE-2022-42312, CVE-2022-42313, CVE-2022-42314, CVE-2022-42315, CVE-2022-42316, CVE-2022-42317, CVE-2022-42318, CVE-2022-42319, CVE-2022-42320, CVE-2022-42321, CVE-2022-42322, CVE-2022-42323, CVE-2022-42325, CVE-2022-42326

IAVB: 2021-B-0011-S, 2022-B-0048-S

SuSE: SUSE-SU-2022:3928-1