The remote Debian 11 host has packages installed that are affected by multiple vulnerabilities as referenced in the dsa-5272 advisory.

  - insufficient TLB flush for x86 PV guests in shadow mode For migration as well as to work around kernels     unaware of L1TF (see XSA-273), PV guests may be run in shadow paging mode. To address XSA-401, code was     moved inside a function in Xen. This code movement missed a variable changing meaning / value between old     and new code positions. The now wrong use of the variable did lead to a wrong TLB flush condition,     omitting flushes where such are necessary. (CVE-2022-33745)

  - 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)

  - Arm: unbounded memory consumption for 2nd-level page tables Certain actions require e.g. removing pages     from a guest's P2M (Physical-to-Machine) mapping. When large pages are in use to map guest pages in the     2nd-stage page tables, such a removal operation may incur a memory allocation (to replace a large mapping     with individual smaller ones). These memory allocations are taken from the global memory pool. A malicious     guest might be able to cause the global memory pool to be exhausted by manipulating its own P2M mappings.
    (CVE-2022-33747)

  - 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)

  - 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)

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

Detections

Analytics

Debian DSA-5272-1 : xen - security update

high Nessus Plugin ID 167052

Version 1.4