Fedora 36 : xen (2022-07438e12df)

high Nessus Plugin ID 169223

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Synopsis

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

Description

The remote Fedora 36 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2022-07438e12df advisory.

- 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)

- Oxenstored 32->31 bit integer truncation issues Integers in Ocaml are 63 or 31 bits of signed precision.
The Ocaml Xenbus library takes a C uint32_t out of the ring and casts it directly to an Ocaml integer. In 64-bit Ocaml builds this is fine, but in 32-bit builds, it truncates off the most significant bit, and then creates unsigned/signed confusion in the remainder. This in turn can feed a negative value into logic not expecting a negative value, resulting in unexpected exceptions being thrown. The unexpected exception is not handled suitably, creating a busy-loop trying (and failing) to take the bad packet out of the xenstore ring. (CVE-2022-42324)

- 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)

- x86: unintended memory sharing between guests On Intel systems that support the virtualize APIC accesses feature, a guest can read and write the global shared xAPIC page by moving the local APIC out of xAPIC mode. Access to this shared page bypasses the expected isolation that should exist between two guests.
(CVE-2022-42327)

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

Solution

Update the affected xen package.

Plugin Details

Severity: High

ID: 169223

File Name: fedora_2022-07438e12df.nasl

Version: 1.1

Type: local

Agent: unix

Family: Fedora Local Security Checks

Published: 12/23/2022

Updated: 9/8/2023

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

Risk Information

VPR

Risk Factor: High

Score: 7.3

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

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

CVSS Score Source: CVE-2022-42309

CVSS v3

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

Vulnerability Information

CPE: cpe:/o:fedoraproject:fedora:36, p-cpe:/a:fedoraproject:fedora:xen

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

Exploit Ease: No known exploits are available

Patch Publication Date: 11/1/2022

Vulnerability Publication Date: 11/1/2022

Reference Information

CVE: 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-2022-42324, CVE-2022-42325, CVE-2022-42326, CVE-2022-42327

FEDORA: 2022-07438e12df

IAVB: 2022-B-0048-S

Detections

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