CVE-2023-34322
Xen 3.2.0 – 4.15.0
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2023-34322 is a high-severity Improper Check for Dropped Privileges (CWE-273) vulnerability in Xen Xen. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Data Obfuscation (T1001); ranked at the 12th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-6 (Least Privilege) — see the control section below for these in your framework.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-38403
Vulnerability Data
For migration as well as to work around kernels unaware of L1TF (see XSA-273), PV guests may be run in shadow paging mode. Since Xen itself needs to be mapped when PV guests run, Xen and shadowed PV guests run…
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directly the respective shadow page tables. For 64-bit PV guests this means running on the shadow of the guest root page table. In the course of dealing with shortage of memory in the shadow pool associated with a domain, shadows of page tables may be torn down. This tearing down may include the shadow root page table that the CPU in question is presently running on. While a precaution exists to supposedly prevent the tearing down of the underlying live page table, the time window covered by that precaution isn't large enough.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Employing least privilege requires that privilege-dropping operations succeed and are verified before continuing.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Least-privilege policy and enforcement directly motivate privilege-dropping code, yet the control does not address implementation-level verification of the drop.
Secure SDLC activities (code review, static analysis, testing) catch missing or incorrect privilege-drop checks, but eliminating only this one flaw covers only a fraction of the control's broader intent.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
A.5.15 only requires defining policies, determining requirements, and referencing other controls for implementing access rules; it never mandates or performs the specific check for successful privilege drop that would remove CWE-273 from first-party code.
A.5.18 governs the provisioning, review, and revocation of access rights granted to identities; it does not remove or mandate the removal of a first-party code defect in which a privilege drop is attempted but never verified.
Control of privileged utility programs includes ensuring privilege-dropping operations are verified before use.
A.8.2 controls the allocation, review, expiry and use of privileged rights via authorization and policy; it does not remove the code-level defect in which a drop-privileges call is performed without checking its success