{"dataType": "CVE_RECORD", "dataVersion": "5.1", "cveMetadata": {"state": "PUBLISHED", "cveId": "CVE-2021-27854", "assignerOrgId": "37e5125f-f79b-445b-8fad-9564f167944b", "assignerShortName": "certcc", "datePublished": "2022-09-27T18:40:12.738763Z", "dateUpdated": "2024-09-17T02:06:05.625Z", "dateReserved": "2021-03-01T00:00:00"}, "containers": {"cna": {"title": "L2 network filtering bypass using stacked VLAN0, LLC/SNAP headers, and Ethernet to Wifi frame translation", "datePublic": "2022-09-27T00:00:00", "providerMetadata": {"orgId": "37e5125f-f79b-445b-8fad-9564f167944b", "shortName": "certcc", "dateUpdated": "2022-10-12T00:00:00"}, "descriptions": [{"lang": "en", "value": "Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using combinations of VLAN 0 headers, LLC/SNAP headers, and converting frames from Ethernet to Wifi and its reverse."}], "affected": [{"vendor": "IETF", "product": "P802.1Q", "versions": [{"version": "D1.0", "status": "affected", "lessThanOrEqual": "D1.0", "versionType": "custom"}]}, {"vendor": "IETF", "product": "draft-ietf-v6ops-ra-guard", "versions": [{"version": "08", "status": "affected", "lessThanOrEqual": "08", "versionType": "custom"}]}, {"vendor": "IEEE", "product": "802.2", "versions": [{"version": "802.2h-1997", "status": "affected", "lessThanOrEqual": "802.2h-1997", "versionType": "custom"}]}], "references": [{"url": "https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/"}, {"url": "https://standards.ieee.org/ieee/802.2/1048/"}, {"url": "https://standards.ieee.org/ieee/802.1Q/10323/"}, {"url": "https://kb.cert.org/vuls/id/855201"}, {"url": "https://blog.champtar.fr/VLAN0_LLC_SNAP/"}], "credits": [{"lang": "en", "value": "Etienne Champetier (@champtar) <champetier.etienne@gmail.com>"}], "problemTypes": [{"descriptions": [{"type": "CWE", "lang": "en", "description": "CWE-290: Authentication Bypass by Spoofing", "cweId": "CWE-290"}]}], "source": {"discovery": "EXTERNAL"}}, "adp": [{"providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-03T21:33:15.949Z"}, "title": "CVE Program Container", "references": [{"url": "https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/", "tags": ["x_transferred"]}, {"url": "https://standards.ieee.org/ieee/802.2/1048/", "tags": ["x_transferred"]}, {"url": "https://standards.ieee.org/ieee/802.1Q/10323/", "tags": ["x_transferred"]}, {"url": "https://kb.cert.org/vuls/id/855201", "tags": ["x_transferred"]}, {"url": "https://blog.champtar.fr/VLAN0_LLC_SNAP/", "tags": ["x_transferred"]}]}]}}

{}

{"configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:ieee:ieee_802.2:*:*:*:*:*:*:*:*", "matchCriteriaId": "D5B0DDC2-21C5-4682-9AA2-055BF7C722DA", "versionEndIncluding": "802.2h-1997", "vulnerable": true}], "negate": false, "operator": "OR"}]}, {"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:ietf:p802.1q:*:*:*:*:*:*:*:*", "matchCriteriaId": "94105D2E-950F-4290-8840-301FA908BC8C", "versionEndIncluding": "d1.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using combinations of VLAN 0 headers, LLC/SNAP headers, and converting frames from Ethernet to Wifi and its reverse."}, {"lang": "es", "value": "Las capacidades de filtrado de red de capa 2, como la protecci\u00f3n RA de IPv6, pueden omitirse usando combinaciones de encabezados VLAN 0, encabezados LLC/SNAP y convirtiendo tramas de Ethernet a Wifi y su inversa"}], "id": "CVE-2021-27854", "lastModified": "2022-10-12T13:15:10.407", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "ADJACENT_NETWORK", "availabilityImpact": "NONE", "baseScore": 4.7, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 1.4, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2022-09-27T19:15:09.240", "references": [{"source": "cret@cert.org", "url": "https://blog.champtar.fr/VLAN0_LLC_SNAP/"}, {"source": "cret@cert.org", "tags": ["Vendor Advisory"], "url": "https://datatracker.ietf.org/doc/draft-ietf-v6ops-ra-guard/08/"}, {"source": "cret@cert.org", "url": "https://kb.cert.org/vuls/id/855201"}, {"source": "cret@cert.org", "tags": ["Vendor Advisory"], "url": "https://standards.ieee.org/ieee/802.1Q/10323/"}, {"source": "cret@cert.org", "tags": ["Vendor Advisory"], "url": "https://standards.ieee.org/ieee/802.2/1048/"}], "sourceIdentifier": "cret@cert.org", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-290"}], "source": "nvd@nist.gov", "type": "Primary"}, {"description": [{"lang": "en", "value": "CWE-290"}], "source": "cret@cert.org", "type": "Secondary"}]}

{"acknowledgement": "Red Hat would like to thank Etienne Champetier for reporting this issue.", "bugzilla": {"description": "kernel: layer 2 network filtering capabilities bypass / wifi", "id": "2010816", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2010816"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.3", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N", "status": "draft"}, "details": ["Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using combinations of VLAN 0 headers, LLC/SNAP headers, and converting frames from Ethernet to Wifi and its reverse.", "Layer 2 network filtering capabilities such as IPv6 RA guard can be bypassed using combinations of VLAN 0 headers, LLC/SNAP headers and Ethernet to Wifi frame translation."], "name": "CVE-2021-27854", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2021-09-27T10:30:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2021-27854\nhttps://nvd.nist.gov/vuln/detail/CVE-2021-27854"], "statement": "Red Hat deems this to be a configuration issue. There is no vulnerability in the Linux kernel itself, there is a lot of ways to misuse the filtering facilities provided by the kernel and do insecure filtering rules, but you also have everything to actually set up secure rules.", "threat_severity": "Moderate"}