CWE-434
AllowedUnrestricted Upload of File with Dangerous Type
Abstraction: Base · Status: Draft
The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.
6008 vulnerabilities reference this CWE, most recent first.
GHSA-7W9P-PR7X-MJW2
Vulnerability from github – Published: 2025-04-24 18:31 – Updated: 2025-10-22 00:33SAP NetWeaver Visual Composer Metadata Uploader is not protected with a proper authorization, allowing unauthenticated agent to upload potentially malicious executable binaries that could severely harm the host system. This could significantly affect the confidentiality, integrity, and availability of the targeted system.
{
"affected": [],
"aliases": [
"CVE-2025-31324"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-04-24T17:15:35Z",
"severity": "CRITICAL"
},
"details": "SAP NetWeaver Visual Composer Metadata Uploader is not protected with a proper authorization, allowing unauthenticated agent to upload potentially malicious executable binaries that could severely harm the host system. This could significantly affect the confidentiality, integrity, and availability of the targeted system.",
"id": "GHSA-7w9p-pr7x-mjw2",
"modified": "2025-10-22T00:33:17Z",
"published": "2025-04-24T18:31:08Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-31324"
},
{
"type": "WEB",
"url": "https://me.sap.com/notes/3594142"
},
{
"type": "WEB",
"url": "https://onapsis.com/blog/active-exploitation-of-sap-vulnerability-cve-2025-31324"
},
{
"type": "WEB",
"url": "https://url.sap/sapsecuritypatchday"
},
{
"type": "WEB",
"url": "https://www.bleepingcomputer.com/news/security/sap-fixes-suspected-netweaver-zero-day-exploited-in-attacks"
},
{
"type": "WEB",
"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-31324"
},
{
"type": "WEB",
"url": "https://www.theregister.com/2025/04/25/sap_netweaver_patch"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-7WCR-M737-MCHR
Vulnerability from github – Published: 2026-07-15 12:32 – Updated: 2026-07-15 12:32The Grav API plugin (getgrav/grav-plugin-api) before 1.0.3 contains a file upload extension bypass in the API media controller. HandlesMediaUploads::validateFileExtension() inspects only the final file extension via pathinfo($filename, PATHINFO_EXTENSION), so a user with api.media.write permission can upload a file with a double extension such as shell.php.jpg to bypass the dangerous extensions blocklist. The web server may then execute the file as PHP, resulting in remote code execution.
{
"affected": [],
"aliases": [
"CVE-2026-61457"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-15T12:18:20Z",
"severity": "MODERATE"
},
"details": "The Grav API plugin (getgrav/grav-plugin-api) before 1.0.3 contains a file upload extension bypass in the API media controller. HandlesMediaUploads::validateFileExtension() inspects only the final file extension via pathinfo($filename, PATHINFO_EXTENSION), so a user with api.media.write permission can upload a file with a double extension such as shell.php.jpg to bypass the dangerous extensions blocklist. The web server may then execute the file as PHP, resulting in remote code execution.",
"id": "GHSA-7wcr-m737-mchr",
"modified": "2026-07-15T12:32:04Z",
"published": "2026-07-15T12:32:04Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/getgrav/grav/security/advisories/GHSA-66v2-vxxf-xc3v"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-61457"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/grav-before-remote-code-execution-via-file-upload-extension-bypass"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/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-7WFW-GFCH-RF74
Vulnerability from github – Published: 2026-05-15 21:31 – Updated: 2026-05-15 21:31WordPress Plugin WP Super Edit 2.5.4 and earlier contains an unrestricted file upload vulnerability in the FCKeditor component that allows attackers to upload dangerous file types without validation. Attackers can upload arbitrary files through the filemanager upload endpoint to achieve remote code execution and complete system compromise.
{
"affected": [],
"aliases": [
"CVE-2021-47965"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-05-15T19:16:56Z",
"severity": "CRITICAL"
},
"details": "WordPress Plugin WP Super Edit 2.5.4 and earlier contains an unrestricted file upload vulnerability in the FCKeditor component that allows attackers to upload dangerous file types without validation. Attackers can upload arbitrary files through the filemanager upload endpoint to achieve remote code execution and complete system compromise.",
"id": "GHSA-7wfw-gfch-rf74",
"modified": "2026-05-15T21:31:32Z",
"published": "2026-05-15T21:31:32Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-47965"
},
{
"type": "WEB",
"url": "https://wordpress.org"
},
{
"type": "WEB",
"url": "https://wordpress.org/plugins/wp-super-edit"
},
{
"type": "WEB",
"url": "https://www.exploit-db.com/exploits/49839"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/wordpress-plugin-wp-super-edit-unrestricted-file-upload"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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-7WG4-W577-22H4
Vulnerability from github – Published: 2025-08-20 09:30 – Updated: 2026-04-23 15:38Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Imran Emu TC Testimonials allows Stored XSS. This issue affects TC Testimonials: from n/a through 1.1.1.
{
"affected": [],
"aliases": [
"CVE-2025-49410"
],
"database_specific": {
"cwe_ids": [
"CWE-434",
"CWE-79"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-08-20T08:15:36Z",
"severity": "MODERATE"
},
"details": "Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027) vulnerability in Imran Emu TC Testimonials allows Stored XSS. This issue affects TC Testimonials: from n/a through 1.1.1.",
"id": "GHSA-7wg4-w577-22h4",
"modified": "2026-04-23T15:38:36Z",
"published": "2025-08-20T09:30:39Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-49410"
},
{
"type": "WEB",
"url": "https://patchstack.com/database/Wordpress/Plugin/otw-portfolio-manager/vulnerability/wordpress-portfolio-manager-pro-plugin-3-8-arbitrary-file-upload-vulnerability?_s_id=cve"
},
{
"type": "WEB",
"url": "https://patchstack.com/database/wordpress/plugin/tc-testimonial/vulnerability/wordpress-tc-testimonials-plugin-1-1-1-cross-site-scripting-xss-vulnerability?_s_id=cve"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:L",
"type": "CVSS_V3"
}
]
}
GHSA-7WHJ-W45H-CCJG
Vulnerability from github – Published: 2024-06-27 03:30 – Updated: 2024-06-27 03:30The Auto Featured Image plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the 'create_post_attachment_from_url' function in all versions up to, and including, 1.2. This makes it possible for authenticated attackers, with contributor-level and above permissions, to upload arbitrary files on the affected site's server which may make remote code execution possible.
{
"affected": [],
"aliases": [
"CVE-2024-6054"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-06-27T03:15:50Z",
"severity": "HIGH"
},
"details": "The Auto Featured Image plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the \u0027create_post_attachment_from_url\u0027 function in all versions up to, and including, 1.2. This makes it possible for authenticated attackers, with contributor-level and above permissions, to upload arbitrary files on the affected site\u0027s server which may make remote code execution possible.",
"id": "GHSA-7whj-w45h-ccjg",
"modified": "2024-06-27T03:30:56Z",
"published": "2024-06-27T03:30:56Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-6054"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/browser/auto-featured-image/tags/1.2/auto-featured-image.php#L167"
},
{
"type": "WEB",
"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/4d1512c2-75c1-405b-8bb4-f42ec69159a7?source=cve"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-7WQV-XJF3-X35V
Vulnerability from github – Published: 2026-06-19 19:35 – Updated: 2026-06-19 19:35Impact
The default file upload extension blocklist can be bypassed by appending a trailing dot to a filename whose extension would otherwise be blocked (e.g. poc.svg.). The trailing dot causes the extension parser to extract an empty string, which short-circuits the blocklist check, and the attacker-controlled Content-Type is forwarded to the storage adapter unchanged. Storage adapters that persist and serve the provided Content-Type (such as S3 or GCS) then serve the file with an active type such as image/svg+xml, enabling stored XSS when a victim opens the file URL. The default GridFS adapter is not affected because it sets X-Content-Type-Options: nosniff on responses.
Patches
A filename ending in a dot is now treated as extensionless. When the parser produces an empty extension, the request handler falls back to validating the Content-Type subtype against the configured extension blocklist, matching the path that already catches truly extensionless uploads with a dangerous Content-Type. This is a follow-up to the previous fix GHSA-vr5f-2r24-w5hc.
Workarounds
Configure the storage adapter or CDN to derive Content-Type from the filename extension instead of using the stored Content-Type, or replace the default blocklist with an explicit allowlist of needed file extensions.
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "parse-server"
},
"ranges": [
{
"events": [
{
"introduced": "9.0.0"
},
{
"fixed": "9.9.1-alpha.4"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 8.6.78"
},
"package": {
"ecosystem": "npm",
"name": "parse-server"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "8.6.79"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-53724"
],
"database_specific": {
"cwe_ids": [
"CWE-434",
"CWE-79"
],
"github_reviewed": true,
"github_reviewed_at": "2026-06-19T19:35:11Z",
"nvd_published_at": "2026-06-12T19:16:30Z",
"severity": "LOW"
},
"details": "### Impact\n\nThe default file upload extension blocklist can be bypassed by appending a trailing dot to a filename whose extension would otherwise be blocked (e.g. `poc.svg.`). The trailing dot causes the extension parser to extract an empty string, which short-circuits the blocklist check, and the attacker-controlled Content-Type is forwarded to the storage adapter unchanged. Storage adapters that persist and serve the provided Content-Type (such as S3 or GCS) then serve the file with an active type such as `image/svg+xml`, enabling stored XSS when a victim opens the file URL. The default GridFS adapter is not affected because it sets `X-Content-Type-Options: nosniff` on responses.\n\n### Patches\n\nA filename ending in a dot is now treated as extensionless. When the parser produces an empty extension, the request handler falls back to validating the Content-Type subtype against the configured extension blocklist, matching the path that already catches truly extensionless uploads with a dangerous Content-Type. This is a follow-up to the previous fix [GHSA-vr5f-2r24-w5hc](https://github.com/parse-community/parse-server/security/advisories/GHSA-vr5f-2r24-w5hc).\n\n### Workarounds\n\nConfigure the storage adapter or CDN to derive Content-Type from the filename extension instead of using the stored Content-Type, or replace the default blocklist with an explicit allowlist of needed file extensions.",
"id": "GHSA-7wqv-xjf3-x35v",
"modified": "2026-06-19T19:35:11Z",
"published": "2026-06-19T19:35:11Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/parse-community/parse-server/security/advisories/GHSA-7wqv-xjf3-x35v"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53724"
},
{
"type": "WEB",
"url": "https://github.com/parse-community/parse-server/pull/10489"
},
{
"type": "WEB",
"url": "https://github.com/parse-community/parse-server/pull/10490"
},
{
"type": "PACKAGE",
"url": "https://github.com/parse-community/parse-server"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N",
"type": "CVSS_V4"
}
],
"summary": "parse-server: Stored XSS via trailing-dot filename bypassing file upload extension blocklist"
}
GHSA-7WX4-FJQ2-2HJG
Vulnerability from github – Published: 2023-11-30 15:30 – Updated: 2023-11-30 15:30An authenticated privileged attacker could upload a specially crafted zip to the EspoCRM server in version 7.2.5, via the extension deployment form, which could lead to arbitrary PHP code execution.
{
"affected": [],
"aliases": [
"CVE-2023-5966"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-11-30T14:15:13Z",
"severity": "CRITICAL"
},
"details": "An authenticated privileged attacker could upload a specially crafted zip to the EspoCRM server in version 7.2.5, via the extension deployment form, which could lead to arbitrary PHP code execution.",
"id": "GHSA-7wx4-fjq2-2hjg",
"modified": "2023-11-30T15:30:24Z",
"published": "2023-11-30T15:30:24Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-5966"
},
{
"type": "WEB",
"url": "https://www.incibe.es/en/incibe-cert/notices/aviso/multiple-vulnerabilities-espocrm"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-7X75-92HX-VR86
Vulnerability from github – Published: 2026-04-20 21:31 – Updated: 2026-04-20 21:31Vvveb CMS 1.0.8 contains a remote code execution vulnerability in its media upload handler that allows authenticated attackers to execute arbitrary operating system commands by uploading a PHP webshell with a .phtml extension. Attackers can bypass the extension deny-list and upload malicious files to the publicly accessible media directory, then request the file over HTTP to achieve full server compromise.
{
"affected": [],
"aliases": [
"CVE-2026-6249"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-04-20T20:16:48Z",
"severity": "HIGH"
},
"details": "Vvveb CMS 1.0.8 contains a remote code execution vulnerability in its media upload handler that allows authenticated attackers to execute arbitrary operating system commands by uploading a PHP webshell with a .phtml extension. Attackers can bypass the extension deny-list and upload malicious files to the publicly accessible media directory, then request the file over HTTP to achieve full server compromise.",
"id": "GHSA-7x75-92hx-vr86",
"modified": "2026-04-20T21:31:45Z",
"published": "2026-04-20T21:31:45Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-6249"
},
{
"type": "WEB",
"url": "https://github.com/givanz/Vvveb/commit/23ac0e8c758d80f3c4d9224763c8b2359648270e"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/vvveb-cms-remote-code-execution-via-media-upload"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/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-7X7J-52GX-4H55
Vulnerability from github – Published: 2023-12-18 21:30 – Updated: 2023-12-21 21:30The Vrm 360 3D Model Viewer WordPress plugin through 1.2.1 is vulnerable to arbitrary file upload due to insufficient checks in a plugin shortcode.
{
"affected": [],
"aliases": [
"CVE-2023-4311"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-12-18T20:15:08Z",
"severity": "HIGH"
},
"details": "The Vrm 360 3D Model Viewer WordPress plugin through 1.2.1 is vulnerable to arbitrary file upload due to insufficient checks in a plugin shortcode.",
"id": "GHSA-7x7j-52gx-4h55",
"modified": "2023-12-21T21:30:29Z",
"published": "2023-12-18T21:30:27Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-4311"
},
{
"type": "WEB",
"url": "https://wpscan.com/vulnerability/21950116-1a69-4848-9da0-e912096c0fce"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-7X97-5M4C-4JVM
Vulnerability from github – Published: 2025-11-19 18:31 – Updated: 2025-11-19 18:31eGovFramework/egovframe-common-components versions up to and including 4.3.1 contain an unauthenticated file upload vulnerability via the /utl/wed/insertImage.do and /utl/wed/insertImageCk.do image upload endpoints. These controllers accept multipart requests without authentication, pass the uploaded content to a shared upload helper, and store the file on the server under a framework-controlled path. The framework then returns a download URL that can be used to retrieve the uploaded content, including an attacker-controlled Content-Type within the limits of the image upload functionality. While a filename extension whitelist is enforced, the attacker fully controls the file contents. The response MIME type used is also attacker-controlled when the file is served up to version < 4.1.2. Since version 4.1.2, it is possible to download any image uploaded with any whitelisted content type. But any file uploaded other than an image will be served with the application/octet-stream content type (the content type is no longer controlled by the attacker since version 4.1.2). This enables an unauthenticated attacker to use any affected application as a persistent file hosting service for arbitrary content under the application's origin. KISA/KrCERT has identified this unpatched vulnerability as "KVE-2023-5280."
{
"affected": [],
"aliases": [
"CVE-2025-34336"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-11-19T17:15:49Z",
"severity": "MODERATE"
},
"details": "eGovFramework/egovframe-common-components versions up to and including 4.3.1 contain an unauthenticated file upload vulnerability via the /utl/wed/insertImage.do and /utl/wed/insertImageCk.do image upload endpoints. These controllers accept multipart requests without authentication, pass the uploaded content to a shared upload helper, and store the file on the server under a framework-controlled path. The framework then returns a download URL that can be used to retrieve the uploaded content, including an attacker-controlled Content-Type within the limits of the image upload functionality. While a filename extension whitelist is enforced, the attacker fully controls the file contents. The response MIME type used is also attacker-controlled when the file is served up to version \u003c 4.1.2. Since version 4.1.2, it is possible to download any image uploaded with any whitelisted content type. But any file uploaded other than an image will be served with the `application/octet-stream` content type (the content type is no longer controlled by the attacker since version 4.1.2). This enables an unauthenticated attacker to use any affected application as a persistent file hosting service for arbitrary content under the application\u0027s origin. KISA/KrCERT has identified this unpatched vulnerability as \"KVE-2023-5280.\"",
"id": "GHSA-7x97-5m4c-4jvm",
"modified": "2025-11-19T18:31:21Z",
"published": "2025-11-19T18:31:21Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-34336"
},
{
"type": "WEB",
"url": "https://github.com/eGovFramework/egovframe-common-components"
},
{
"type": "WEB",
"url": "https://pierrekim.github.io/advisories/2025-egovframe.txt"
},
{
"type": "WEB",
"url": "https://pierrekim.github.io/blog/2025-11-20-egovframe-2-vulnerabilities.html"
},
{
"type": "WEB",
"url": "https://www.egovframe.go.kr/eng/sub.do?menuNo=2"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/egovframework-unauthenticated-file-upload-via-web-editor-image-upload-endpoints"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/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"
}
]
}
Mitigation
Generate a new, unique filename for an uploaded file instead of using the user-supplied filename, so that no external input is used at all.[REF-422] [REF-423]
Mitigation MIT-21
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.
Mitigation
Consider storing the uploaded files outside of the web document root entirely. Then, use other mechanisms to deliver the files dynamically. [REF-423]
Mitigation MIT-5
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.
- For example, limiting filenames to alphanumeric characters can help to restrict the introduction of unintended file extensions.
Mitigation
Define a very limited set of allowable extensions and only generate filenames that end in these extensions. Consider the possibility of XSS (CWE-79) before allowing .html or .htm file types.
Mitigation
Strategy: Input Validation
Ensure that only one extension is used in the filename. Some web servers, including some versions of Apache, may process files based on inner extensions so that "filename.php.gif" is fed to the PHP interpreter.[REF-422] [REF-423]
Mitigation
When running on a web server that supports case-insensitive filenames, perform case-insensitive evaluations of the extensions that are provided.
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
Do not rely exclusively on sanity checks of file contents to ensure that the file is of the expected type and size. It may be possible for an attacker to hide code in some file segments that will still be executed by the server. For example, GIF images may contain a free-form comments field.
Mitigation
Do not rely exclusively on the MIME content type or filename attribute when determining how to render a file. Validating the MIME content type and ensuring that it matches the extension is only a partial solution.
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-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.
CAPEC-1: Accessing Functionality Not Properly Constrained by ACLs
In applications, particularly web applications, access to functionality is mitigated by an authorization framework. This framework maps Access Control Lists (ACLs) to elements of the application's functionality; particularly URL's for web apps. In the case that the administrator failed to specify an ACL for a particular element, an attacker may be able to access it with impunity. An attacker with the ability to access functionality not properly constrained by ACLs can obtain sensitive information and possibly compromise the entire application. Such an attacker can access resources that must be available only to users at a higher privilege level, can access management sections of the application, or can run queries for data that they otherwise not supposed to.