CVE-2020-15567

{"id": "CVE-2020-15567", "metrics": {"cvssMetricV2": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"version": "2.0", "baseScore": 4.4, "accessVector": "LOCAL", "vectorString": "AV:L/AC:M/Au:N/C:P/I:P/A:P", "authentication": "NONE", "integrityImpact": "PARTIAL", "accessComplexity": "MEDIUM", "availabilityImpact": "PARTIAL", "confidentialityImpact": "PARTIAL"}, "acInsufInfo": false, "impactScore": 6.4, "baseSeverity": "MEDIUM", "obtainAllPrivilege": false, "exploitabilityScore": 3.4, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}], "cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "CHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 6.0, "exploitabilityScore": 1.1}]}, "published": "2020-07-07T13:15:10.243", "references": [{"url": "http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00024.html", "tags": ["Mailing List", "Third Party Advisory"], "source": "cve@mitre.org"}, {"url": "http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00031.html", "tags": ["Mailing List", "Third Party Advisory"], "source": "cve@mitre.org"}, {"url": "http://www.openwall.com/lists/oss-security/2020/07/07/6", "tags": ["Mailing List", "Third Party Advisory"], "source": "cve@mitre.org"}, {"url": "http://xenbits.xen.org/xsa/advisory-328.html", "tags": ["Mitigation", "Patch", "Vendor Advisory"], "source": "cve@mitre.org"}, {"url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MXESCOVI7AVRNC7HEAMFM7PMEO6D3AUH/", "source": "cve@mitre.org"}, {"url": "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VB3QJJZV23Z2IDYEMIHELWYSQBUEW6JP/", "source": "cve@mitre.org"}, {"url": "https://security.gentoo.org/glsa/202007-02", "tags": ["Third Party Advisory"], "source": "cve@mitre.org"}, {"url": "https://www.debian.org/security/2020/dsa-4723", "tags": ["Third Party Advisory"], "source": "cve@mitre.org"}], "vulnStatus": "Modified", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-362"}]}], "descriptions": [{"lang": "en", "value": "An issue was discovered in Xen through 4.13.x, allowing Intel guest OS users to gain privileges or cause a denial of service because of non-atomic modification of a live EPT PTE. When mapping guest EPT (nested paging) tables, Xen would in some circumstances use a series of non-atomic bitfield writes. Depending on the compiler version and optimisation flags, Xen might expose a dangerous partially written PTE to the hardware, which an attacker might be able to race to exploit. A guest administrator or perhaps even an unprivileged guest user might be able to cause denial of service, data corruption, or privilege escalation. Only systems using Intel CPUs are vulnerable. Systems using AMD CPUs, and Arm systems, are not vulnerable. Only systems using nested paging (hap, aka nested paging, aka in this case Intel EPT) are vulnerable. Only HVM and PVH guests can exploit the vulnerability. The presence and scope of the vulnerability depends on the precise optimisations performed by the compiler used to build Xen. If the compiler generates (a) a single 64-bit write, or (b) a series of read-modify-write operations in the same order as the source code, the hypervisor is not vulnerable. For example, in one test build using GCC 8.3 with normal settings, the compiler generated multiple (unlocked) read-modify-write operations in source-code order, which did not constitute a vulnerability. We have not been able to survey compilers; consequently we cannot say which compiler(s) might produce vulnerable code (with which code-generation options). The source code clearly violates the C rules, and thus should be considered vulnerable."}, {"lang": "es", "value": "Se detect\u00f3 un problema en Xen versiones hasta 4.13.x, que permite a usuarios del Sistema Operativo invitado de Intel alcanzar privilegios o causar una denegaci\u00f3n de servicio debido a una modificaci\u00f3n no at\u00f3mica de un EPT PTE en vivo. Al mapear tablas EPT (paginaci\u00f3n anidada) invitadas, Xen en algunas circunstancias usa una serie de escrituras de campo de bits no at\u00f3micas. Dependiendo de la versi\u00f3n del compilador y los indicadores de optimizaci\u00f3n, Xen podr\u00eda exponer un PTE peligroso parcialmente escrito al hardware, a un atacante podr\u00eda ser capaz de una carrera para una explotaci\u00f3n. Un administrador invitado o tal vez incluso un usuario invitado no privilegiado podr\u00eda causar una denegaci\u00f3n de servicio, corrupci\u00f3n de datos o una escalada de privilegios. Solo los sistemas que utilizan los CPU Intel son vulnerables. Los sistemas que usan CPU AMD y sistemas Arm no son vulnerables. Solo los sistemas que usan paginaci\u00f3n anidada (hap, tambi\u00e9n se conoce como paginaci\u00f3n anidada, tambi\u00e9n se conoce en este caso como Intel EPT) son vulnerables. Solo los invitados HVM y PVH pueden explotar la vulnerabilidad. La presencia y el alcance de la vulnerabilidad dependen de las optimizaciones precisas llevadas a cabo por el compilador usado para construir Xen. Si el compilador genera (a) una sola escritura de 64 bits, o (b) una serie de operaciones de lectura-modificaci\u00f3n-escritura en el mismo orden que el c\u00f3digo fuente, el hipervisor no es vulnerable. Por ejemplo, en una compilaci\u00f3n de prueba usando GCC versi\u00f3n 8.3 con configuraciones normales, el compilador generaba m\u00faltiples operaciones de lectura-modificaci\u00f3n-escritura (desbloqueadas) seg\u00fan el c\u00f3digo fuente, lo que no constituy\u00f3 una vulnerabilidad. No hemos sido capaces de encuestar a los compiladores; en consecuencia, no podemos decir qu\u00e9 compilador(es) podr\u00edan producir c\u00f3digo vulnerable (con qu\u00e9 opciones de generaci\u00f3n de c\u00f3digo). El c\u00f3digo fuente viola claramente las reglas C y, por lo tanto, debe ser considerado vulnerable"}], "lastModified": "2023-11-07T03:17:41.213", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "16D16A83-7BD8-4FF1-BCBD-17EF7697D221", "versionEndIncluding": "4.13.1"}], "operator": "OR"}]}, {"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "07B237A9-69A3-4A9C-9DA0-4E06BD37AE73"}], "operator": "OR"}]}, {"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "B620311B-34A3-48A6-82DF-6F078D7A4493"}, {"criteria": "cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "B009C22E-30A4-4288-BCF6-C3E81DEAF45A"}], "operator": "OR"}]}, {"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "80F0FA5D-8D3B-4C0E-81E2-87998286AF33"}, {"criteria": "cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "36D96259-24BD-44E2-96D9-78CE1D41F956"}], "operator": "OR"}]}], "sourceIdentifier": "cve@mitre.org"}