cve-2021-29492
Vulnerability from cvelistv5
Published
2021-05-28 21:00
Modified
2024-08-03 22:11
Severity
8.1 (High) - cvssV3_1 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
Bypass of path matching rules using escaped slash characters
References
SourceURLTags
security-advisories@github.comhttps://github.com/envoyproxy/envoy/security/advisories/GHSA-4987-27fx-x6cfMitigation, Third Party Advisory
Impacted products
VendorProduct
envoyproxyenvoy
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          "value": "Envoy is a cloud-native edge/middle/service proxy. Envoy does not decode escaped slash sequences `%2F` and `%5C` in HTTP URL paths in versions 1.18.2 and before. A remote attacker may craft a path with escaped slashes, e.g. `/something%2F..%2Fadmin`, to bypass access control, e.g. a block on `/admin`. A backend server could then decode slash sequences and normalize path and provide an attacker access beyond the scope provided for by the access control policy. ### Impact Escalation of Privileges when using RBAC or JWT filters with enforcement based on URL path. Users with back end servers that interpret `%2F` and `/` and `%5C` and `\\` interchangeably are impacted. ### Attack Vector URL paths containing escaped slash characters delivered by untrusted client. Patches in versions 1.18.3, 1.17.3, 1.16.4, 1.15.5 contain new path normalization option to decode escaped slash characters. As a workaround, if back end servers treat `%2F` and `/` and `%5C` and `\\` interchangeably and a URL path based access control is configured, one may reconfigure the back end server to not treat `%2F` and `/` and `%5C` and `\\` interchangeably."
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Como soluci\u00f3n, si los servidores finales tratan `%2F` y `/` y `%5C` y `\\\\` indistintamente y se configura un control de acceso basado en la ruta de la URL, se puede reconfigurar el servidor final para que no trate `%2F` y `/` y `%5C` y `\\\\` indistintamente\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"CHANGED\",\"confidentialityImpact\":\"LOW\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"LOW\",\"baseScore\":8.3,\"baseSeverity\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":3.7},{\"source\":\"security-advisories@github.com\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\",\"baseScore\":8.1,\"baseSeverity\":\"HIGH\"},\"exploitabilityScore\":2.2,\"impactScore\":5.9}],\"cvssMetricV2\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"2.0\",\"vectorString\":\"AV:N/AC:L/Au:N/C:P/I:P/A:P\",\"accessVector\":\"NETWORK\",\"accessComplexity\":\"LOW\",\"authentication\":\"NONE\",\"confidentialityImpact\":\"PARTIAL\",\"integrityImpact\":\"PARTIAL\",\"availabilityImpact\":\"PARTIAL\",\"baseScore\":7.5},\"baseSeverity\":\"HIGH\",\"exploitabilityScore\":10.0,\"impactScore\":6.4,\"acInsufInfo\":false,\"obtainAllPrivilege\":false,\"obtainUserPrivilege\":false,\"obtainOtherPrivilege\":false,\"userInteractionRequired\":false}]},\"weaknesses\":[{\"source\":\"security-advisories@github.com\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-22\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*\",\"versionEndExcluding\":\"1.15.5\",\"matchCriteriaId\":\"EE9E311E-85FF-42AA-B0A3-C138D436932D\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"1.16.0\",\"versionEndExcluding\":\"1.16.4\",\"matchCriteriaId\":\"D36D66BB-9C95-4E59-AA78-6824ACCB89D7\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"1.17.0\",\"versionEndExcluding\":\"1.17.3\",\"matchCriteriaId\":\"D502D5F9-38A7-46B1-890D-2A177B76AEBB\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"1.18.0\",\"versionEndExcluding\":\"1.18.3\",\"matchCriteriaId\":\"BA3D8EC7-7D60-41C5-9770-3521DB6F7650\"}]}]}],\"references\":[{\"url\":\"https://github.com/envoyproxy/envoy/security/advisories/GHSA-4987-27fx-x6cf\",\"source\":\"security-advisories@github.com\",\"tags\":[\"Mitigation\",\"Third Party Advisory\"]}]}}"
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}


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