CWE-22
Allowed-with-ReviewImproper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Abstraction: Base · Status: Stable
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
13064 vulnerabilities reference this CWE, most recent first.
GHSA-FCRF-87F5-3X6H
Vulnerability from github – Published: 2024-10-05 15:30 – Updated: 2026-04-01 18:31Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in Martin Greenwood WPSPX allows PHP Local File Inclusion.This issue affects WPSPX: from n/a through 1.0.2.
{
"affected": [],
"aliases": [
"CVE-2024-44034"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-10-05T13:15:13Z",
"severity": "HIGH"
},
"details": "Improper Limitation of a Pathname to a Restricted Directory (\u0027Path Traversal\u0027) vulnerability in Martin Greenwood WPSPX allows PHP Local File Inclusion.This issue affects WPSPX: from n/a through 1.0.2.",
"id": "GHSA-fcrf-87f5-3x6h",
"modified": "2026-04-01T18:31:55Z",
"published": "2024-10-05T15:30:26Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-44034"
},
{
"type": "WEB",
"url": "https://patchstack.com/database/Wordpress/Plugin/wpspx/vulnerability/wordpress-wpspx-plugin-1-0-2-local-file-inclusion-vulnerability?_s_id=cve"
},
{
"type": "WEB",
"url": "https://patchstack.com/database/vulnerability/wpspx/wordpress-wpspx-plugin-1-0-2-local-file-inclusion-vulnerability?_s_id=cve"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-FCV2-XGW5-PQXF
Vulnerability from github – Published: 2026-01-22 20:28 – Updated: 2026-02-27 21:37Summary
The legacy TUF client pkg/tuf/client.go, which supports caching target files to disk, constructs a filesystem path by joining a cache base directory with a target name sourced from signed target metadata, but it does not validate that the resulting path stays within the cache base directory.
Note that this should only affect clients that are directly using the TUF client in sigstore/sigstore or are using an older version of Cosign. As this TUF client implementation is deprecated, users should migrate to https://github.com/sigstore/sigstore-go/tree/main/pkg/tuf as soon as possible.
Note that this does not affect users of the public Sigstore deployment, where TUF metadata is validated by a quorum of trusted collaborators.
Impact
A malicious TUF repository can trigger arbitrary file overwriting, limited to the permissions that the calling process has.
Workarounds
Users can disable disk caching for the legacy client by setting SIGSTORE_NO_CACHE=true in the environment, migrate to https://github.com/sigstore/sigstore-go/tree/main/pkg/tuf, or upgrade to the latest sigstore/sigstore release.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 1.10.3"
},
"package": {
"ecosystem": "Go",
"name": "github.com/sigstore/sigstore"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.10.4"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-24137"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": true,
"github_reviewed_at": "2026-01-22T20:28:56Z",
"nvd_published_at": "2026-01-23T00:15:52Z",
"severity": "MODERATE"
},
"details": "## Summary\n\nThe legacy TUF client `pkg/tuf/client.go`, which supports caching target files to disk, constructs a filesystem path by joining a cache base directory with a target name sourced from signed target metadata, but it does not validate that the resulting path stays within the cache base directory.\n\nNote that this should only affect clients that are directly using the TUF client in sigstore/sigstore or are using an older version of Cosign. As this TUF client implementation is deprecated, users should migrate to https://github.com/sigstore/sigstore-go/tree/main/pkg/tuf as soon as possible.\n\nNote that this does not affect users of the public Sigstore deployment, where TUF metadata is validated by a quorum of trusted collaborators. \n\n## Impact\n\nA malicious TUF repository can trigger arbitrary file overwriting, limited to the permissions that the calling process has.\n\n## Workarounds\n\nUsers can disable disk caching for the legacy client by setting `SIGSTORE_NO_CACHE=true` in the environment, migrate to https://github.com/sigstore/sigstore-go/tree/main/pkg/tuf, or upgrade to the latest sigstore/sigstore release.",
"id": "GHSA-fcv2-xgw5-pqxf",
"modified": "2026-02-27T21:37:24Z",
"published": "2026-01-22T20:28:56Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/sigstore/sigstore/security/advisories/GHSA-fcv2-xgw5-pqxf"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-24137"
},
{
"type": "WEB",
"url": "https://github.com/sigstore/sigstore/commit/8ec410a2993ea78083aecf0e473a85453039496e"
},
{
"type": "PACKAGE",
"url": "https://github.com/sigstore/sigstore"
},
{
"type": "WEB",
"url": "https://github.com/sigstore/sigstore/releases/tag/v1.10.4"
},
{
"type": "WEB",
"url": "https://pkg.go.dev/vuln/GO-2026-4358"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:N/I:H/A:N",
"type": "CVSS_V3"
}
],
"summary": "sigstore legacy TUF client allows for arbitrary file writes with target cache path traversal"
}
GHSA-FCW4-WWQM-M8CF
Vulnerability from github – Published: 2026-06-19 20:51 – Updated: 2026-06-19 20:51We have released version 5.24.0 of the Grafana Operator. This patch includes a MODERATE severity security fix for a path traversal/privilege escalation vulnerability in the Grafana Operator.
Summary
The Grafana Operator supports loading dashboards & library panels using the jsonnet data templating language. The jsonnet expression is evaluated in the context of the operator manager pod.
Impact
It is possible for a malicious user who can create Dashboard or LibraryPanel resources for a Grafana instance to obtain the Kubernetes service account token of the Grafana Operator manager.
Affected versions
All Grafana Operator versions <= 5.23
Solutions and mitigations
All installations should be upgraded as soon as possible.
As a workaround, the following ValidatingAdmissionPolicy prevent the creation or modification of jsonnet based resources:
apiVersion: admissionregistration.k8s.io/v1
kind: ValidatingAdmissionPolicy
metadata:
name: "prevent-jsonnet-dashboards"
spec:
failurePolicy: Fail
matchConstraints:
resourceRules:
- apiGroups: ["grafana.integreatly.org"]
apiVersions: ["v1beta1"]
operations: ["CREATE", "UPDATE"]
resources: ["grafanadashboards", "grafanalibrarypanels"]
validations:
- expression: "!has(object.spec.jsonnetLib)"
---
apiVersion: admissionregistration.k8s.io/v1
kind: ValidatingAdmissionPolicyBinding
metadata:
name: "prevent-jsonnet-dashboards-clusterwide"
spec:
policyName: "prevent-jsonnet-dashboards"
validationActions: [Deny]
Acknowledgement
We would like to thank Artem Cherezov for responsibly disclosing the vulnerability.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 5.23.0"
},
"package": {
"ecosystem": "Go",
"name": "github.com/grafana/grafana-operator/v5"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "5.24.0"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Go",
"name": "github.com/grafana/grafana-operator"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"last_affected": "2.0.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-11769"
],
"database_specific": {
"cwe_ids": [
"CWE-200",
"CWE-22"
],
"github_reviewed": true,
"github_reviewed_at": "2026-06-19T20:51:16Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "We have released version 5.24.0 of the Grafana Operator. This patch includes a MODERATE severity security fix for a path traversal/privilege escalation vulnerability in the Grafana Operator.\n\n\n### Summary\n\nThe Grafana Operator supports loading dashboards \u0026 library panels using the jsonnet data templating language. The jsonnet expression is evaluated in the context of the operator manager pod.\n### Impact\n\nIt is possible for a malicious user who can create `Dashboard` or `LibraryPanel` resources for a `Grafana` instance to obtain the Kubernetes service account token of the Grafana Operator manager.\n\n### Affected versions\n\nAll Grafana Operator versions \u003c= 5.23\n\n### Solutions and mitigations\n\nAll installations should be upgraded as soon as possible.\n\nAs a workaround, the following ValidatingAdmissionPolicy prevent the creation or modification of jsonnet based resources:\n```\napiVersion: admissionregistration.k8s.io/v1\nkind: ValidatingAdmissionPolicy\nmetadata:\n name: \"prevent-jsonnet-dashboards\"\nspec:\n failurePolicy: Fail\n matchConstraints:\n resourceRules:\n - apiGroups: [\"grafana.integreatly.org\"]\n apiVersions: [\"v1beta1\"]\n operations: [\"CREATE\", \"UPDATE\"]\n resources: [\"grafanadashboards\", \"grafanalibrarypanels\"]\n validations:\n - expression: \"!has(object.spec.jsonnetLib)\"\n---\napiVersion: admissionregistration.k8s.io/v1\nkind: ValidatingAdmissionPolicyBinding\nmetadata:\n name: \"prevent-jsonnet-dashboards-clusterwide\"\nspec:\n policyName: \"prevent-jsonnet-dashboards\"\n validationActions: [Deny]\n```\n\n\n### Acknowledgement\n\nWe would like to thank [Artem Cherezov](https://github.com/cherez0ff) for responsibly disclosing the vulnerability.",
"id": "GHSA-fcw4-wwqm-m8cf",
"modified": "2026-06-19T20:51:16Z",
"published": "2026-06-19T20:51:16Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/grafana/grafana-operator/security/advisories/GHSA-fcw4-wwqm-m8cf"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-11769"
},
{
"type": "PACKAGE",
"url": "https://github.com/grafana/grafana-operator"
},
{
"type": "WEB",
"url": "https://grafana.com/security/security-advisories/cve-2026-11769"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Grafana Operator: Privilege escalation from namespace admin to cluster admin via GrafanaDashboard jsonnetLib fileName"
}
GHSA-FF2W-M935-V55X
Vulnerability from github – Published: 2021-12-09 00:01 – Updated: 2021-12-10 00:01A relative path traversal [CWE-23] vulnerabiltiy in FortiOS versions 7.0.0 and 7.0.1 and FortiProxy verison 7.0.0 may allow an unauthenticated, unauthorized attacker to inject path traversal character sequences to disclose sensitive information of the server via the GET request of the login page.
{
"affected": [],
"aliases": [
"CVE-2021-41024"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-12-08T13:15:00Z",
"severity": "HIGH"
},
"details": "A relative path traversal [CWE-23] vulnerabiltiy in FortiOS versions 7.0.0 and 7.0.1 and FortiProxy verison 7.0.0 may allow an unauthenticated, unauthorized attacker to inject path traversal character sequences to disclose sensitive information of the server via the GET request of the login page.",
"id": "GHSA-ff2w-m935-v55x",
"modified": "2021-12-10T00:01:00Z",
"published": "2021-12-09T00:01:01Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-41024"
},
{
"type": "WEB",
"url": "https://fortiguard.com/advisory/FG-IR-21-181"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-FF4V-VG5P-42PF
Vulnerability from github – Published: 2026-04-27 18:32 – Updated: 2026-04-27 18:32A path traversal vulnerability in the UI/static component of leonvanzyl autocoder commit 79d02a allows attackers to read arbitrary files via sending crafted URL path containing traversal sequences.
{
"affected": [],
"aliases": [
"CVE-2026-30351"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-04-27T16:16:43Z",
"severity": "HIGH"
},
"details": "A path traversal vulnerability in the UI/static component of leonvanzyl autocoder commit 79d02a allows attackers to read arbitrary files via sending crafted URL path containing traversal sequences.",
"id": "GHSA-ff4v-vg5p-42pf",
"modified": "2026-04-27T18:32:06Z",
"published": "2026-04-27T18:32:06Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-30351"
},
{
"type": "WEB",
"url": "https://gist.github.com/syphonetic/0201da0fda7f700e0701d82d755d78a0"
},
{
"type": "WEB",
"url": "https://github.com/leonvanzyl/autocoder"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-FF5C-56M7-VC75
Vulnerability from github – Published: 2025-03-20 12:32 – Updated: 2025-03-21 21:24OpenWebUI version 0.3.0 contains a vulnerability in the audio API endpoint /audio/api/v1/transcriptions that allows for arbitrary file upload. The application performs insufficient validation on the file.content_type and allows user-controlled filenames, leading to a path traversal vulnerability. This can be exploited by an authenticated user to overwrite critical files within the Docker container, potentially leading to remote code execution as the root user.
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "open-webui"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.5.17"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2024-8060"
],
"database_specific": {
"cwe_ids": [
"CWE-22",
"CWE-434"
],
"github_reviewed": true,
"github_reviewed_at": "2025-03-21T21:24:09Z",
"nvd_published_at": "2025-03-20T10:15:40Z",
"severity": "HIGH"
},
"details": "OpenWebUI version 0.3.0 contains a vulnerability in the audio API endpoint `/audio/api/v1/transcriptions` that allows for arbitrary file upload. The application performs insufficient validation on the `file.content_type` and allows user-controlled filenames, leading to a path traversal vulnerability. This can be exploited by an authenticated user to overwrite critical files within the Docker container, potentially leading to remote code execution as the root user.",
"id": "GHSA-ff5c-56m7-vc75",
"modified": "2025-03-21T21:24:09Z",
"published": "2025-03-20T12:32:47Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-8060"
},
{
"type": "WEB",
"url": "https://github.com/open-webui/open-webui/commit/613a087387c094e71ee91d29c015195ef401e160"
},
{
"type": "PACKAGE",
"url": "https://github.com/open-webui/open-webui"
},
{
"type": "WEB",
"url": "https://huntr.com/bounties/a3b1a4b7-c723-496d-842c-844cc0988fe9"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "Open WebUI allows Remote Code Execution via Arbitrary File Upload to /audio/api/v1/transcriptions"
}
GHSA-FF64-FQRG-XH7J
Vulnerability from github – Published: 2026-06-12 12:31 – Updated: 2026-06-12 12:31The iVEC-IEI Virtualization Edge Computer developed by IEI Integration Corp has a Arbitrary File Read vulnerability, allowing privileged remote attackers to access files outside the intended directory scope.
{
"affected": [],
"aliases": [
"CVE-2026-11844"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-06-12T10:16:21Z",
"severity": "MODERATE"
},
"details": "The iVEC-IEI Virtualization Edge Computer developed by IEI Integration Corp has a Arbitrary File Read vulnerability, allowing privileged remote attackers to access files outside the intended directory scope.",
"id": "GHSA-ff64-fqrg-xh7j",
"modified": "2026-06-12T12:31:33Z",
"published": "2026-06-12T12:31:33Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-11844"
},
{
"type": "WEB",
"url": "https://www.twcert.org.tw/en/cp-139-10970-e4b21-2.html"
},
{
"type": "WEB",
"url": "https://www.twcert.org.tw/tw/cp-132-10969-4c4e2-1.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-FF6P-C229-3P2R
Vulnerability from github – Published: 2022-05-14 01:50 – Updated: 2022-05-14 01:50statics/ueditor/php/vendor/Local.class.php in YUNUCMS 1.1.5 allows arbitrary file deletion via the statics/ueditor/php/controller.php?action=remove key parameter, as demonstrated by using directory traversal to delete the install.lock file.
{
"affected": [],
"aliases": [
"CVE-2018-19181"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2018-11-11T17:29:00Z",
"severity": "HIGH"
},
"details": "statics/ueditor/php/vendor/Local.class.php in YUNUCMS 1.1.5 allows arbitrary file deletion via the statics/ueditor/php/controller.php?action=remove key parameter, as demonstrated by using directory traversal to delete the install.lock file.",
"id": "GHSA-ff6p-c229-3p2r",
"modified": "2022-05-14T01:50:05Z",
"published": "2022-05-14T01:50:05Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2018-19181"
},
{
"type": "WEB",
"url": "https://github.com/doublefast/yunucms/issues/1"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-FF76-QQWC-MJ6R
Vulnerability from github – Published: 2022-05-17 02:51 – Updated: 2022-05-17 02:51HTTP Exploit in eMLi Portal in AuroMeera Technometrix Pvt. Ltd. eMLi allows an Attacker to View Restricted Information or (even more seriously) execute powerful commands on the web server which can lead to a full compromise of the system via Directory Path Traversal, as demonstrated by reading core-emli/Storage. The affected versions are eMLi School Management 1.0, eMLi College Campus Management 1.0, and eMLi University Management 1.0.
{
"affected": [],
"aliases": [
"CVE-2017-7258"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2017-03-29T20:59:00Z",
"severity": "HIGH"
},
"details": "HTTP Exploit in eMLi Portal in AuroMeera Technometrix Pvt. Ltd. eMLi allows an Attacker to View Restricted Information or (even more seriously) execute powerful commands on the web server which can lead to a full compromise of the system via Directory Path Traversal, as demonstrated by reading core-emli/Storage. The affected versions are eMLi School Management 1.0, eMLi College Campus Management 1.0, and eMLi University Management 1.0.",
"id": "GHSA-ff76-qqwc-mj6r",
"modified": "2022-05-17T02:51:03Z",
"published": "2022-05-17T02:51:03Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2017-7258"
},
{
"type": "WEB",
"url": "https://sudoat.blogspot.in/2017/03/path-traversal-vulnerability-in-emli.html"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/97255"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-FF9C-2V27-XQMF
Vulnerability from github – Published: 2022-05-17 02:43 – Updated: 2022-05-17 02:43Absolute path traversal vulnerability in the MDC YouTube Downloader plugin 2.1.0 for WordPress allows remote attackers to read arbitrary files via a full pathname in the file parameter to includes/download.php.
{
"affected": [],
"aliases": [
"CVE-2015-5469"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2017-05-23T04:29:00Z",
"severity": "HIGH"
},
"details": "Absolute path traversal vulnerability in the MDC YouTube Downloader plugin 2.1.0 for WordPress allows remote attackers to read arbitrary files via a full pathname in the file parameter to includes/download.php.",
"id": "GHSA-ff9c-2v27-xqmf",
"modified": "2022-05-17T02:43:14Z",
"published": "2022-05-17T02:43:14Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2015-5469"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2015/07/07/1"
},
{
"type": "WEB",
"url": "http://www.openwall.com/lists/oss-security/2015/07/10/5"
},
{
"type": "WEB",
"url": "http://www.vapid.dhs.org/advisory.php?v=133"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
Mitigation MIT-5.1
Strategy: Input Validation
- Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
- When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."
- Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
- When validating filenames, use stringent allowlists that limit the character set to be used. If feasible, only allow a single "." character in the filename to avoid weaknesses such as CWE-23, and exclude directory separators such as "/" to avoid CWE-36. Use a list of allowable file extensions, which will help to avoid CWE-434.
- Do not rely exclusively on a filtering mechanism that removes potentially dangerous characters. This is equivalent to a denylist, which may be incomplete (CWE-184). For example, filtering "/" is insufficient protection if the filesystem also supports the use of "\" as a directory separator. Another possible error could occur when the filtering is applied in a way that still produces dangerous data (CWE-182). For example, if "../" sequences are removed from the ".../...//" string in a sequential fashion, two instances of "../" would be removed from the original string, but the remaining characters would still form the "../" string.
Mitigation MIT-15
For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
Mitigation MIT-20.1
Strategy: Input Validation
- Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.
- Use a built-in path canonicalization function (such as realpath() in C) that produces the canonical version of the pathname, which effectively removes ".." sequences and symbolic links (CWE-23, CWE-59). This includes:
- realpath() in C
- getCanonicalPath() in Java
- GetFullPath() in ASP.NET
- realpath() or abs_path() in Perl
- realpath() in PHP
Mitigation MIT-4
Strategy: Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid [REF-1482].
Mitigation MIT-29
Strategy: Firewall
Use an application firewall that can detect attacks against this weakness. It can be beneficial in cases in which the code cannot be fixed (because it is controlled by a third party), as an emergency prevention measure while more comprehensive software assurance measures are applied, or to provide defense in depth [REF-1481].
Mitigation MIT-17
Strategy: Environment Hardening
Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.
Mitigation MIT-21.1
Strategy: Enforcement by Conversion
- When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
- For example, ID 1 could map to "inbox.txt" and ID 2 could map to "profile.txt". Features such as the ESAPI AccessReferenceMap [REF-185] provide this capability.
Mitigation MIT-22
Strategy: Sandbox or Jail
- Run the code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which files can be accessed in a particular directory or which commands can be executed by the software.
- OS-level examples include the Unix chroot jail, AppArmor, and SELinux. In general, managed code may provide some protection. For example, java.io.FilePermission in the Java SecurityManager allows the software to specify restrictions on file operations.
- This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise.
- Be careful to avoid CWE-243 and other weaknesses related to jails.
Mitigation MIT-34
Strategy: Attack Surface Reduction
- Store library, include, and utility files outside of the web document root, if possible. Otherwise, store them in a separate directory and use the web server's access control capabilities to prevent attackers from directly requesting them. One common practice is to define a fixed constant in each calling program, then check for the existence of the constant in the library/include file; if the constant does not exist, then the file was directly requested, and it can exit immediately.
- This significantly reduces the chance of an attacker being able to bypass any protection mechanisms that are in the base program but not in the include files. It will also reduce the attack surface.
Mitigation MIT-39
- Ensure that error messages only contain minimal details that are useful to the intended audience and no one else. The messages need to strike the balance between being too cryptic (which can confuse users) or being too detailed (which may reveal more than intended). The messages should not reveal the methods that were used to determine the error. Attackers can use detailed information to refine or optimize their original attack, thereby increasing their chances of success.
- If errors must be captured in some detail, record them in log messages, but consider what could occur if the log messages can be viewed by attackers. Highly sensitive information such as passwords should never be saved to log files.
- Avoid inconsistent messaging that might accidentally tip off an attacker about internal state, such as whether a user account exists or not.
- In the context of path traversal, error messages which disclose path information can help attackers craft the appropriate attack strings to move through the file system hierarchy.
Mitigation MIT-16
Strategy: Environment Hardening
When using PHP, configure the application so that it does not use register_globals. During implementation, develop the application so that it does not rely on this feature, but be wary of implementing a register_globals emulation that is subject to weaknesses such as CWE-95, CWE-621, and similar issues.
CAPEC-126: Path Traversal
An adversary uses path manipulation methods to exploit insufficient input validation of a target to obtain access to data that should be not be retrievable by ordinary well-formed requests. A typical variety of this attack involves specifying a path to a desired file together with dot-dot-slash characters, resulting in the file access API or function traversing out of the intended directory structure and into the root file system. By replacing or modifying the expected path information the access function or API retrieves the file desired by the attacker. These attacks either involve the attacker providing a complete path to a targeted file or using control characters (e.g. path separators (/ or \) and/or dots (.)) to reach desired directories or files.
CAPEC-64: Using Slashes and URL Encoding Combined to Bypass Validation Logic
This attack targets the encoding of the URL combined with the encoding of the slash characters. An attacker can take advantage of the multiple ways of encoding a URL and abuse the interpretation of the URL. A URL may contain special character that need special syntax handling in order to be interpreted. Special characters are represented using a percentage character followed by two digits representing the octet code of the original character (%HEX-CODE). For instance US-ASCII space character would be represented with %20. This is often referred as escaped ending or percent-encoding. Since the server decodes the URL from the requests, it may restrict the access to some URL paths by validating and filtering out the URL requests it received. An attacker will try to craft an URL with a sequence of special characters which once interpreted by the server will be equivalent to a forbidden URL. It can be difficult to protect against this attack since the URL can contain other format of encoding such as UTF-8 encoding, Unicode-encoding, etc.
CAPEC-76: Manipulating Web Input to File System Calls
An attacker manipulates inputs to the target software which the target software passes to file system calls in the OS. The goal is to gain access to, and perhaps modify, areas of the file system that the target software did not intend to be accessible.
CAPEC-78: Using Escaped Slashes in Alternate Encoding
This attack targets the use of the backslash in alternate encoding. An adversary can provide a backslash as a leading character and causes a parser to believe that the next character is special. This is called an escape. By using that trick, the adversary tries to exploit alternate ways to encode the same character which leads to filter problems and opens avenues to attack.
CAPEC-79: Using Slashes in Alternate Encoding
This attack targets the encoding of the Slash characters. An adversary would try to exploit common filtering problems related to the use of the slashes characters to gain access to resources on the target host. Directory-driven systems, such as file systems and databases, typically use the slash character to indicate traversal between directories or other container components. For murky historical reasons, PCs (and, as a result, Microsoft OSs) choose to use a backslash, whereas the UNIX world typically makes use of the forward slash. The schizophrenic result is that many MS-based systems are required to understand both forms of the slash. This gives the adversary many opportunities to discover and abuse a number of common filtering problems. The goal of this pattern is to discover server software that only applies filters to one version, but not the other.