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-22CP-HQ23-FV85
Vulnerability from github – Published: 2025-11-26 03:30 – Updated: 2025-12-03 18:30Unauthenticated Arbitrary File Upload (upgrade_contents.php) in DB Electronica Telecomunicazioni S.p.A. Mozart FM Transmitter versions 30, 50, 100, 300, 500, 1000, 2000, 3000, 3500, 6000, 7000 allows an attacker to perform Missing signature validation allows uploading malicious firmware packages.
The firmware upgrade endpoint in upgrade_contents.php accepts arbitrary file uploads without validating file headers, cryptographic signatures, or enforcing .tgz format requirements, allowing malicious firmware injection. This endpoint also subsequently provides ways for arbitrary file uploads and subsequent remote code execution
{
"affected": [],
"aliases": [
"CVE-2025-66255"
],
"database_specific": {
"cwe_ids": [
"CWE-345",
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-11-26T01:16:08Z",
"severity": "CRITICAL"
},
"details": "Unauthenticated Arbitrary File Upload (upgrade_contents.php) in DB Electronica Telecomunicazioni S.p.A. Mozart FM Transmitter versions 30, 50, 100, 300, 500, 1000, 2000, 3000, 3500, 6000, 7000 allows an attacker to perform Missing signature validation allows uploading malicious firmware packages.\u00a0\nThe firmware upgrade endpoint in `upgrade_contents.php` accepts arbitrary file uploads without validating file headers, cryptographic signatures, or enforcing .tgz format requirements, allowing malicious firmware injection. This endpoint also subsequently provides ways for arbitrary file uploads and subsequent remote code execution",
"id": "GHSA-22cp-hq23-fv85",
"modified": "2025-12-03T18:30:21Z",
"published": "2025-11-26T03:30:21Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-66255"
},
{
"type": "WEB",
"url": "https://www.abdulmhsblog.com/posts/webfmvulns"
}
],
"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:N/SC:H/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-22F5-Q5GP-64WX
Vulnerability from github – Published: 2024-08-12 15:30 – Updated: 2026-02-17 21:31ThreatSonar Anti-Ransomware from TeamT5 does not properly validate the content of uploaded files. Remote attackers with administrator privileges on the product platform can upload malicious files, which can be used to execute arbitrary system command on the server.
{
"affected": [],
"aliases": [
"CVE-2024-7694"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-08-12T13:38:58Z",
"severity": "HIGH"
},
"details": "ThreatSonar Anti-Ransomware from TeamT5 does not properly validate the content of uploaded files. Remote attackers with administrator privileges on the product platform can upload malicious files, which can be used to execute arbitrary system command on the server.",
"id": "GHSA-22f5-q5gp-64wx",
"modified": "2026-02-17T21:31:12Z",
"published": "2024-08-12T15:30:53Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-7694"
},
{
"type": "WEB",
"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-7694"
},
{
"type": "WEB",
"url": "https://www.twcert.org.tw/en/cp-139-8000-e5a5c-2.html"
},
{
"type": "WEB",
"url": "https://www.twcert.org.tw/tw/cp-132-7998-d76dd-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:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-22FP-MF44-F2MQ
Vulnerability from github – Published: 2025-04-18 20:24 – Updated: 2025-05-27 19:56Description
This advisory follows the security advisory GHSA-79w7-vh3h-8g4j published by the yt-dlp/yt-dlp project to aid remediation of the issue in the ytdl-org/youtube-dl project.
Vulnerability
youtube-dl does not limit the extensions of downloaded files, which could lead to arbitrary filenames being created in the download folder (and path traversal on Windows).
Impact
Since youtube-dl also reads config from the working directory (and, on Windows, executables will be executed from the youtube-dl directory by default) the vulnerability could allow the unwanted execution of local code, including downloads masquerading as, eg, subtitles.
Patches
The versions of youtube-dl listed as Patched remediate this vulnerability by disallowing path separators and whitelisting allowed extensions. As a result, some very uncommon extensions might not get downloaded.
Master code d42a222 or later and nightly builds tagged 2024-07-03 or later contain the remediation.
Workarounds
Any/all of the below considerations may limit exposure in case it is necessary to use a vulnerable version
* have .%(ext)s at the end of the output template
* download from websites that you trust
* do not download to a directory within the executable search PATH or other sensitive locations, such as your user directory or system directories
* in Windows versions that support it, set NoDefaultCurrentDirectoryInExePath to prevent the cmd shell's executable search adding the default directory before PATH
* consider that the path traversal vulnerability as a result of resolving non_existent_dir\..\..\target does not exist in Linux or macOS
* ensure the extension of the media to download is a common video/audio/... one (use --get-filename)
* omit any of the subtitle options (--write-subs/--write-srt, --write-auto-subs/--write-automatic-subs, --all-subs).
References
- GHSA-79w7-vh3h-8g4j
- https://github.com/ytdl-org/youtube-dl/pull/32830
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "youtube-dl"
},
"ranges": [
{
"events": [
{
"introduced": "2015.01.25"
},
{
"last_affected": "2021.12.17"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-434",
"CWE-669"
],
"github_reviewed": true,
"github_reviewed_at": "2025-04-18T20:24:07Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"details": "#### Description\nThis advisory follows the security advisory [GHSA-79w7-vh3h-8g4j published by the _yt-dlp/yt-dlp_ project](https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-79w7-vh3h-8g4j) to aid remediation of the issue in the _ytdl-org/youtube-dl_ project.\n\n### Vulnerability\n_youtube-dl_ does not limit the extensions of downloaded files, which could lead to arbitrary filenames being created in the download folder (and path traversal on Windows). \n\n### Impact\nSince _youtube-dl_ also reads config from the working directory (and, on Windows, executables will be executed from the _youtube-dl_ directory by default) the vulnerability could allow the unwanted execution of local code, including downloads masquerading as, eg, subtitles.\n\n### Patches\nThe versions of _youtube-dl_ listed as _Patched_ remediate this vulnerability by disallowing path separators and whitelisting allowed extensions. As a result, some very uncommon extensions might not get downloaded.\n\n**Master code d42a222 or later and nightly builds tagged 2024-07-03 or later** contain the remediation.\n\n### Workarounds\nAny/all of the below considerations may limit exposure in case it is necessary to use a vulnerable version\n* have `.%(ext)s` at the end of the output template\n* download from websites that you trust\n* do not download to a directory within the executable search `PATH` or other sensitive locations, such as your user directory or system directories\n* in Windows versions that support it, set [`NoDefaultCurrentDirectoryInExePath`](https://stackoverflow.com/a/50118548) to prevent the _cmd_ shell\u0027s executable search adding the default directory before `PATH`\n* consider that the path traversal vulnerability as a result of resolving `non_existent_dir\\..\\..\\target` does not exist in Linux or macOS\n* ensure the extension of the media to download is a common video/audio/... one (use `--get-filename`)\n* omit any of the subtitle options (`--write-subs`/` --write-srt`, `--write-auto-subs`/`--write-automatic-subs`, `--all-subs`).\n\n### References\n* [GHSA-79w7-vh3h-8g4j](https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-79w7-vh3h-8g4j)\n* https://github.com/ytdl-org/youtube-dl/pull/32830",
"id": "GHSA-22fp-mf44-f2mq",
"modified": "2025-05-27T19:56:40Z",
"published": "2025-04-18T20:24:07Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/dirkf/youtube-dl/security/advisories/GHSA-22fp-mf44-f2mq"
},
{
"type": "WEB",
"url": "https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-79w7-vh3h-8g4j"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-38519"
},
{
"type": "WEB",
"url": "https://github.com/ytdl-org/youtube-dl/pull/32830"
},
{
"type": "WEB",
"url": "https://github.com/ytdl-org/youtube-dl/commit/d42a222ed541b96649396ef00e19552aef0f09ec"
},
{
"type": "PACKAGE",
"url": "https://github.com/dirkf/youtube-dl"
},
{
"type": "ADVISORY",
"url": "https://securitylab.github.com/advisories/GHSL-2024-089_youtube-dl"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "youtube-dl vulnerable to file system modification and RCE through improper file-extension sanitization"
}
GHSA-22M6-QPWV-V2XP
Vulnerability from github – Published: 2026-07-16 09:32 – Updated: 2026-07-16 21:30The Customer Reviews for WooCommerce WordPress plugin before 5.113.0 does not perform authentication, capability, or nonce checks on one of its media upload AJAX actions when the review media attachment feature is enabled, allowing unauthenticated users to upload media files (bounded to an image and video allowlist) to the Media Library and create attachment posts, leading to media library pollution and disk space exhaustion.
{
"affected": [],
"aliases": [
"CVE-2026-12684"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-16T07:16:47Z",
"severity": "MODERATE"
},
"details": "The Customer Reviews for WooCommerce WordPress plugin before 5.113.0 does not perform authentication, capability, or nonce checks on one of its media upload AJAX actions when the review media attachment feature is enabled, allowing unauthenticated users to upload media files (bounded to an image and video allowlist) to the Media Library and create attachment posts, leading to media library pollution and disk space exhaustion.",
"id": "GHSA-22m6-qpwv-v2xp",
"modified": "2026-07-16T21:30:34Z",
"published": "2026-07-16T09:32:16Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-12684"
},
{
"type": "WEB",
"url": "https://wpscan.com/vulnerability/169d3455-dd98-4b0b-b6c1-6c9c28aa9707"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L",
"type": "CVSS_V3"
}
]
}
GHSA-22Q3-4V32-4M7C
Vulnerability from github – Published: 2024-07-15 18:31 – Updated: 2024-08-01 15:31Tmall_demo v2024.07.03 was discovered to contain an arbitrary file upload via the component uploadUserHeadImage.
{
"affected": [],
"aliases": [
"CVE-2024-40553"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-07-15T16:15:03Z",
"severity": "MODERATE"
},
"details": "Tmall_demo v2024.07.03 was discovered to contain an arbitrary file upload via the component uploadUserHeadImage.",
"id": "GHSA-22q3-4v32-4m7c",
"modified": "2024-08-01T15:31:59Z",
"published": "2024-07-15T18:31:15Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-40553"
},
{
"type": "WEB",
"url": "https://gitee.com/project_team/Tmall_demo/issues/IAANVC"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-22WM-VGH4-2J44
Vulnerability from github – Published: 2022-05-24 16:58 – Updated: 2024-04-04 02:09Yealink phones through 2019-08-04 do not properly check user roles in POST requests. Consequently, the default User account (with a password of user) can make admin requests via HTTP.
{
"affected": [],
"aliases": [
"CVE-2019-14656"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2019-10-08T13:15:00Z",
"severity": "HIGH"
},
"details": "Yealink phones through 2019-08-04 do not properly check user roles in POST requests. Consequently, the default User account (with a password of user) can make admin requests via HTTP.",
"id": "GHSA-22wm-vgh4-2j44",
"modified": "2024-04-04T02:09:49Z",
"published": "2022-05-24T16:58:01Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-14656"
},
{
"type": "WEB",
"url": "https://sway.office.com/3pCb559LYVuT0eig"
},
{
"type": "WEB",
"url": "http://cerebusforensics.com/yealink/exploit.html"
}
],
"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-234X-7QJ3-R3FJ
Vulnerability from github – Published: 2022-05-17 02:26 – Updated: 2022-05-17 02:26Arbitrary file upload vulnerability in com/dotmarketing/servlets/AjaxFileUploadServlet.class in dotCMS 4.1.1 allows remote authenticated administrators to upload .jsp files to arbitrary locations via directory traversal sequences in the fieldName parameter to servlets/ajax_file_upload. This results in arbitrary code execution by requesting the .jsp file at a /assets URI.
{
"affected": [],
"aliases": [
"CVE-2017-11466"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2017-07-20T00:29:00Z",
"severity": "HIGH"
},
"details": "Arbitrary file upload vulnerability in com/dotmarketing/servlets/AjaxFileUploadServlet.class in dotCMS 4.1.1 allows remote authenticated administrators to upload .jsp files to arbitrary locations via directory traversal sequences in the fieldName parameter to servlets/ajax_file_upload. This results in arbitrary code execution by requesting the .jsp file at a /assets URI.",
"id": "GHSA-234x-7qj3-r3fj",
"modified": "2022-05-17T02:26:22Z",
"published": "2022-05-17T02:26:22Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2017-11466"
},
{
"type": "WEB",
"url": "https://github.com/dotCMS/core/issues/12131"
},
{
"type": "WEB",
"url": "https://packetstormsecurity.com/files/143383/dotcms411-shell.txt"
},
{
"type": "WEB",
"url": "http://seclists.org/fulldisclosure/2017/Jul/33"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-2365-P872-CMM2
Vulnerability from github – Published: 2022-05-14 01:44 – Updated: 2022-05-14 01:44ClipperCMS 1.3.3 allows remote authenticated administrators to upload .htaccess files.
{
"affected": [],
"aliases": [
"CVE-2018-19424"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2018-11-21T21:29:00Z",
"severity": "HIGH"
},
"details": "ClipperCMS 1.3.3 allows remote authenticated administrators to upload .htaccess files.",
"id": "GHSA-2365-p872-cmm2",
"modified": "2022-05-14T01:44:59Z",
"published": "2022-05-14T01:44:59Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2018-19424"
},
{
"type": "WEB",
"url": "https://github.com/ClipperCMS/ClipperCMS/issues/495"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-2374-6CVW-QMX6
Vulnerability from github – Published: 2025-10-29 21:44 – Updated: 2025-10-29 21:44Summary
The out-of-box experience for HTML editing allows unauthenticated users to upload files. This opens a potential vector to other security issues and is not needed on most implementations.
Details
The new out-of-box experience blocks that endpoint to unauthenticated users. If there is a real need for the implementation to allow unauthenticated uploads, then the web.config can be edited by the implementer to remove that block and open the endpoint to the public.
{
"affected": [
{
"package": {
"ecosystem": "NuGet",
"name": "Dnn.Platform"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "10.1.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2025-62802"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": true,
"github_reviewed_at": "2025-10-29T21:44:28Z",
"nvd_published_at": "2025-10-28T22:15:38Z",
"severity": "MODERATE"
},
"details": "### Summary\nThe out-of-box experience for HTML editing allows unauthenticated users to upload files. This opens a potential vector to other security issues and is not needed on most implementations.\n\n### Details\nThe new out-of-box experience blocks that endpoint to unauthenticated users. If there is a real need for the implementation to allow unauthenticated uploads, then the web.config can be edited by the implementer to remove that block and open the endpoint to the public.",
"id": "GHSA-2374-6cvw-qmx6",
"modified": "2025-10-29T21:44:28Z",
"published": "2025-10-29T21:44:28Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/dnnsoftware/Dnn.Platform/security/advisories/GHSA-2374-6cvw-qmx6"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-62802"
},
{
"type": "WEB",
"url": "https://github.com/dnnsoftware/Dnn.Platform/commit/6497d3c35217e6e62e50d3ed7c8809eb69e3d06b"
},
{
"type": "PACKAGE",
"url": "https://github.com/dnnsoftware/Dnn.Platform"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N",
"type": "CVSS_V3"
}
],
"summary": "DNN CKEditor Provider allows unauthenticated upload out-of-the-box"
}
GHSA-2377-G2H8-5F9C
Vulnerability from github – Published: 2025-01-27 00:31 – Updated: 2025-01-27 00:31A vulnerability classified as critical was found in needyamin image_gallery 1.0. This vulnerability affects unknown code of the file /admin/gallery.php of the component Cover Image Handler. The manipulation of the argument image leads to unrestricted upload. The attack can be initiated remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.
{
"affected": [],
"aliases": [
"CVE-2025-0722"
],
"database_specific": {
"cwe_ids": [
"CWE-284",
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-01-27T00:15:26Z",
"severity": "MODERATE"
},
"details": "A vulnerability classified as critical was found in needyamin image_gallery 1.0. This vulnerability affects unknown code of the file /admin/gallery.php of the component Cover Image Handler. The manipulation of the argument image leads to unrestricted upload. The attack can be initiated remotely. The exploit has been disclosed to the public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.",
"id": "GHSA-2377-g2h8-5f9c",
"modified": "2025-01-27T00:31:33Z",
"published": "2025-01-27T00:31:33Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-0722"
},
{
"type": "WEB",
"url": "https://vuldb.com/?ctiid.293482"
},
{
"type": "WEB",
"url": "https://vuldb.com/?id.293482"
},
{
"type": "WEB",
"url": "https://vuldb.com/?submit.482822"
},
{
"type": "WEB",
"url": "https://www.websecurityinsights.my.id/2025/01/imagegallery-add-gallery.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:L",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:L/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"
}
]
}
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.