gsd-2021-29492
Vulnerability from gsd
Modified
2023-12-13 01:23
Details
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.
Aliases
Aliases
{ "GSD": { "alias": "CVE-2021-29492", "description": "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.", "id": "GSD-2021-29492", "references": [ "https://www.suse.com/security/cve/CVE-2021-29492.html", "https://access.redhat.com/errata/RHSA-2021:1540", "https://access.redhat.com/errata/RHSA-2021:1538", "https://security.archlinux.org/CVE-2021-29492" ] }, "gsd": { "metadata": { "exploitCode": "unknown", "remediation": "unknown", "reportConfidence": "confirmed", "type": "vulnerability" }, "osvSchema": { "aliases": [ "CVE-2021-29492" ], "details": "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.", "id": "GSD-2021-29492", "modified": "2023-12-13T01:23:37.098195Z", "schema_version": "1.4.0" } }, "namespaces": { "cve.org": { "CVE_data_meta": { "ASSIGNER": "security-advisories@github.com", "ID": "CVE-2021-29492", "STATE": "PUBLIC", "TITLE": "Bypass of path matching rules using escaped slash characters" }, "affects": { "vendor": { "vendor_data": [ { "product": { "product_data": [ { "product_name": "envoy", "version": { "version_data": [ { "version_value": "\u003c= 1.18.2" } ] } } ] }, "vendor_name": "envoyproxy" } ] } }, "data_format": "MITRE", "data_type": "CVE", "data_version": "4.0", "description": { "description_data": [ { "lang": "eng", "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." } ] }, "impact": { "cvss": { "attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.1, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1" } }, "problemtype": { "problemtype_data": [ { "description": [ { "lang": "eng", "value": "CWE-22: Improper Limitation of a Pathname to a Restricted Directory (\u0027Path Traversal\u0027)" } ] } ] }, "references": { "reference_data": [ { "name": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-4987-27fx-x6cf", "refsource": "CONFIRM", "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-4987-27fx-x6cf" } ] }, "source": { "advisory": "GHSA-4987-27fx-x6cf", "discovery": "UNKNOWN" } }, "nvd.nist.gov": { "configurations": { "CVE_data_version": "4.0", "nodes": [ { "children": [], "cpe_match": [ { "cpe23Uri": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*", "cpe_name": [], "versionEndExcluding": "1.15.5", "vulnerable": true }, { "cpe23Uri": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*", "cpe_name": [], "versionEndExcluding": "1.16.4", "versionStartIncluding": "1.16.0", "vulnerable": true }, { "cpe23Uri": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*", "cpe_name": [], "versionEndExcluding": "1.17.3", "versionStartIncluding": "1.17.0", "vulnerable": true }, { "cpe23Uri": "cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*", "cpe_name": [], "versionEndExcluding": "1.18.3", "versionStartIncluding": "1.18.0", "vulnerable": true } ], "operator": "OR" } ] }, "cve": { "CVE_data_meta": { "ASSIGNER": "security-advisories@github.com", "ID": "CVE-2021-29492" }, "data_format": "MITRE", "data_type": "CVE", "data_version": "4.0", "description": { "description_data": [ { "lang": "en", "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." } ] }, "problemtype": { "problemtype_data": [ { "description": [ { "lang": "en", "value": "CWE-22" } ] } ] }, "references": { "reference_data": [ { "name": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-4987-27fx-x6cf", "refsource": "CONFIRM", "tags": [ "Mitigation", "Third Party Advisory" ], "url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-4987-27fx-x6cf" } ] } }, "impact": { "baseMetricV2": { "acInsufInfo": false, "cvssV2": { "accessComplexity": "LOW", "accessVector": "NETWORK", "authentication": "NONE", "availabilityImpact": "PARTIAL", "baseScore": 7.5, "confidentialityImpact": "PARTIAL", "integrityImpact": "PARTIAL", "vectorString": "AV:N/AC:L/Au:N/C:P/I:P/A:P", "version": "2.0" }, "exploitabilityScore": 10.0, "impactScore": 6.4, "obtainAllPrivilege": false, "obtainOtherPrivilege": false, "obtainUserPrivilege": false, "severity": "HIGH", "userInteractionRequired": false }, "baseMetricV3": { "cvssV3": { "attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "LOW", "baseScore": 8.3, "baseSeverity": "HIGH", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "NONE", "scope": "CHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L", "version": "3.1" }, "exploitabilityScore": 3.9, "impactScore": 3.7 } }, "lastModifiedDate": "2021-12-10T18:10Z", "publishedDate": "2021-05-28T21:15Z" } } }
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Sightings
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Nomenclature
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