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.
5966 vulnerabilities reference this CWE, most recent first.
GHSA-X2G8-MG86-PMG4
Vulnerability from github – Published: 2023-10-02 21:30 – Updated: 2024-04-04 08:01File Upload vulnerability in mojoPortal v.2.7.0.0 allows a remote attacker to execute arbitrary code via the Skin Management function.
{
"affected": [],
"aliases": [
"CVE-2023-44009"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-10-02T21:15:34Z",
"severity": "CRITICAL"
},
"details": "File Upload vulnerability in mojoPortal v.2.7.0.0 allows a remote attacker to execute arbitrary code via the Skin Management function.",
"id": "GHSA-x2g8-mg86-pmg4",
"modified": "2024-04-04T08:01:16Z",
"published": "2023-10-02T21:30:17Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-44009"
},
{
"type": "WEB",
"url": "https://github.com/Vietsunshine-Electronic-Solution-JSC/Vulnerability-Disclosures/tree/main/2023/CVE-2023-44009"
},
{
"type": "WEB",
"url": "https://www.mojoportal.com"
}
],
"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"
}
]
}
GHSA-X2MH-PG9F-258M
Vulnerability from github – Published: 2022-06-03 00:01 – Updated: 2022-06-11 00:00In Wedding Management v1.0, there is an arbitrary file upload vulnerability in the picture upload point of "users_edit.php" file.
{
"affected": [],
"aliases": [
"CVE-2022-30820"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2022-06-02T14:15:00Z",
"severity": "HIGH"
},
"details": "In Wedding Management v1.0, there is an arbitrary file upload vulnerability in the picture upload point of \"users_edit.php\" file.",
"id": "GHSA-x2mh-pg9f-258m",
"modified": "2022-06-11T00:00:32Z",
"published": "2022-06-03T00:01:11Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-30820"
},
{
"type": "WEB",
"url": "https://github.com/k0xx11/bug_report/blob/main/vendors/codeastro.com/wedding-management-system/RCE-4.md"
}
],
"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-X2V2-MJ6C-WFP3
Vulnerability from github – Published: 2023-09-20 15:30 – Updated: 2024-04-04 07:46fake_upload.cgi on the Telstra Smart Modem Gen 2 (Arcadyan LH1000), firmware versions < 0.18.15r, allows unauthenticated attackers to upload firmware images and configuration backups, which could allow them to alter the firmware or the configuration on the device, ultimately leading to code execution as root.
{
"affected": [],
"aliases": [
"CVE-2023-43478"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-09-20T14:15:15Z",
"severity": "CRITICAL"
},
"details": "fake_upload.cgi on the Telstra Smart Modem Gen 2 (Arcadyan LH1000), firmware versions \u003c 0.18.15r, allows unauthenticated attackers to upload firmware images and configuration backups, which could allow them to alter the firmware or the configuration on the device, ultimately leading to code execution as root.\u00a0",
"id": "GHSA-x2v2-mj6c-wfp3",
"modified": "2024-04-04T07:46:11Z",
"published": "2023-09-20T15:30:52Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-43478"
},
{
"type": "WEB",
"url": "https://www.tenable.com/security/research/tra-2023-19"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-X2XC-MRMF-Q7PV
Vulnerability from github – Published: 2025-08-08 21:30 – Updated: 2025-08-08 21:30EGallery version 1.2 contains an unauthenticated arbitrary file upload vulnerability in the uploadify.php script. The application fails to validate file types or enforce authentication, allowing remote attackers to upload malicious PHP files directly into the web-accessible egallery/ directory. This results in full remote code execution under the web server context.
{
"affected": [],
"aliases": [
"CVE-2012-10052"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-08-08T19:15:35Z",
"severity": "CRITICAL"
},
"details": "EGallery version 1.2 contains an unauthenticated arbitrary file upload vulnerability in the uploadify.php script. The application fails to validate file types or enforce authentication, allowing remote attackers to upload malicious PHP files directly into the web-accessible egallery/ directory. This results in full remote code execution under the web server context.",
"id": "GHSA-x2xc-mrmf-q7pv",
"modified": "2025-08-08T21:30:40Z",
"published": "2025-08-08T21:30:40Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2012-10052"
},
{
"type": "WEB",
"url": "https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/exploits/unix/webapp/egallery_upload_exec.rb"
},
{
"type": "WEB",
"url": "https://sourceforge.net/projects/e-gallery"
},
{
"type": "WEB",
"url": "https://www.exploit-db.com/exploits/20029"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/egallery-arbitrary-php-file-upload"
},
{
"type": "WEB",
"url": "http://web.archive.org/web/20170128123244/http://www.opensyscom.fr/Actualites/egallery-arbitrary-file-upload-vulnerability.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"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-X34X-F5FQ-583H
Vulnerability from github – Published: 2022-03-03 00:00 – Updated: 2022-03-17 00:04Home Owners Collection Management System v1.0 was discovered to contain an arbitrary file upload vulnerability via the component /student_attendance/index.php. This vulnerability allows attackers to execute arbitrary code via a crafted PHP file.
{
"affected": [],
"aliases": [
"CVE-2022-25016"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2022-03-02T17:15:00Z",
"severity": "CRITICAL"
},
"details": "Home Owners Collection Management System v1.0 was discovered to contain an arbitrary file upload vulnerability via the component /student_attendance/index.php. This vulnerability allows attackers to execute arbitrary code via a crafted PHP file.",
"id": "GHSA-x34x-f5fq-583h",
"modified": "2022-03-17T00:04:11Z",
"published": "2022-03-03T00:00:49Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-25016"
},
{
"type": "WEB",
"url": "https://github.com/lohyt/web-shell-via-file-upload-in-hocms"
}
],
"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"
}
]
}
GHSA-X3C9-P79C-QHQC
Vulnerability from github – Published: 2025-11-24 00:30 – Updated: 2025-11-24 00:30A weakness has been identified in code-projects Online Bidding System 1.0. This issue affects the function categoryadd of the file /administrator/addcategory.php. This manipulation of the argument catimage causes unrestricted upload. The attack is possible to be carried out remotely. The exploit has been made available to the public and could be exploited.
{
"affected": [],
"aliases": [
"CVE-2025-13574"
],
"database_specific": {
"cwe_ids": [
"CWE-284",
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-11-24T00:15:46Z",
"severity": "MODERATE"
},
"details": "A weakness has been identified in code-projects Online Bidding System 1.0. This issue affects the function categoryadd of the file /administrator/addcategory.php. This manipulation of the argument catimage causes unrestricted upload. The attack is possible to be carried out remotely. The exploit has been made available to the public and could be exploited.",
"id": "GHSA-x3c9-p79c-qhqc",
"modified": "2025-11-24T00:30:17Z",
"published": "2025-11-24T00:30:17Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-13574"
},
{
"type": "WEB",
"url": "https://code-projects.org"
},
{
"type": "WEB",
"url": "https://github.com/Yohane-Mashiro/cve/blob/main/upload%201.md"
},
{
"type": "WEB",
"url": "https://vuldb.com/?ctiid.333338"
},
{
"type": "WEB",
"url": "https://vuldb.com/?id.333338"
},
{
"type": "WEB",
"url": "https://vuldb.com/?submit.698717"
},
{
"type": "WEB",
"url": "https://vuldb.com/?submit.698718"
}
],
"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:P/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-X3CF-W64X-4CP2
Vulnerability from github – Published: 2022-05-14 01:04 – Updated: 2023-10-06 17:56An issue was discovered in Symfony 2.7.x before 2.7.50, 2.8.x before 2.8.49, 3.x before 3.4.20, 4.0.x before 4.0.15, 4.1.x before 4.1.9, and 4.2.x before 4.2.1. When using the scalar type hint string in a setter method (e.g. setName(string $name)) of a class that's the data_class of a form, and when a file upload is submitted to the corresponding field instead of a normal text input, then UploadedFile::__toString() is called which will then return and disclose the path of the uploaded file. If combined with a local file inclusion issue in certain circumstances this could escalate it to a Remote Code Execution.
{
"affected": [
{
"package": {
"ecosystem": "Packagist",
"name": "symfony/symfony"
},
"ranges": [
{
"events": [
{
"introduced": "2.7.0"
},
{
"fixed": "2.7.50"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "symfony/symfony"
},
"ranges": [
{
"events": [
{
"introduced": "2.8.0"
},
{
"fixed": "2.8.49"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "symfony/symfony"
},
"ranges": [
{
"events": [
{
"introduced": "3.0.0"
},
{
"fixed": "3.4.20"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "symfony/symfony"
},
"ranges": [
{
"events": [
{
"introduced": "4.0.0"
},
{
"fixed": "4.0.15"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "symfony/symfony"
},
"ranges": [
{
"events": [
{
"introduced": "4.1.0"
},
{
"fixed": "4.1.9"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "symfony/symfony"
},
"ranges": [
{
"events": [
{
"introduced": "4.2.0"
},
{
"fixed": "4.2.1"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "symfony/form"
},
"ranges": [
{
"events": [
{
"introduced": "2.7.0"
},
{
"fixed": "2.7.50"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "symfony/form"
},
"ranges": [
{
"events": [
{
"introduced": "2.8.0"
},
{
"fixed": "2.8.49"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "symfony/form"
},
"ranges": [
{
"events": [
{
"introduced": "3.0.0"
},
{
"fixed": "3.4.20"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "symfony/form"
},
"ranges": [
{
"events": [
{
"introduced": "4.0.0"
},
{
"fixed": "4.0.15"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "symfony/form"
},
"ranges": [
{
"events": [
{
"introduced": "4.1.0"
},
{
"fixed": "4.1.9"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "symfony/form"
},
"ranges": [
{
"events": [
{
"introduced": "4.2.0"
},
{
"fixed": "4.2.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2018-19789"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": true,
"github_reviewed_at": "2023-07-24T19:38:49Z",
"nvd_published_at": "2018-12-18T22:29:00Z",
"severity": "MODERATE"
},
"details": "An issue was discovered in Symfony 2.7.x before 2.7.50, 2.8.x before 2.8.49, 3.x before 3.4.20, 4.0.x before 4.0.15, 4.1.x before 4.1.9, and 4.2.x before 4.2.1. When using the scalar type hint `string` in a setter method (e.g. `setName(string $name)`) of a class that\u0027s the `data_class` of a form, and when a file upload is submitted to the corresponding field instead of a normal text input, then `UploadedFile::__toString()` is called which will then return and disclose the path of the uploaded file. If combined with a local file inclusion issue in certain circumstances this could escalate it to a Remote Code Execution.",
"id": "GHSA-x3cf-w64x-4cp2",
"modified": "2023-10-06T17:56:17Z",
"published": "2022-05-14T01:04:20Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2018-19789"
},
{
"type": "WEB",
"url": "https://github.com/symfony/symfony/commit/b65e6f1a47b68f2713b60cdac9cc3a4af62a2d1c"
},
{
"type": "WEB",
"url": "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/form/CVE-2018-19789.yaml"
},
{
"type": "WEB",
"url": "https://github.com/FriendsOfPHP/security-advisories/blob/master/symfony/symfony/CVE-2018-19789.yaml"
},
{
"type": "PACKAGE",
"url": "https://github.com/symfony/symfony"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2019/03/msg00009.html"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4TD3E7FZIXLVFG3SMFJPDEKPZ26TJOW7"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/JZMRJ7VTHCY5AZK24G4QGX36RLUDTDKE"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/OA4WVFN5FYPIXAPLWZI6N425JHHDSWAZ"
},
{
"type": "WEB",
"url": "https://seclists.org/bugtraq/2019/May/21"
},
{
"type": "WEB",
"url": "https://symfony.com/blog/cve-2018-19789-disclosure-of-uploaded-files-full-path"
},
{
"type": "WEB",
"url": "https://symfony.com/cve-2018-19789"
},
{
"type": "WEB",
"url": "https://web.archive.org/web/20210124224817/http://www.securityfocus.com/bid/106249"
},
{
"type": "WEB",
"url": "https://www.debian.org/security/2019/dsa-4441"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
"type": "CVSS_V3"
}
],
"summary": "Symfony Path Disclosure"
}
GHSA-X3FJ-VM97-72X4
Vulnerability from github – Published: 2023-06-02 15:30 – Updated: 2023-06-02 15:30A vulnerability was found in code-projects Agro-School Management System 1.0 and classified as critical. This issue affects some unknown processing of the file btn_functions.php of the component Attachment Image Handler. The manipulation leads to unrestricted upload. The attack may be initiated remotely. The associated identifier of this vulnerability is VDB-230567.
{
"affected": [],
"aliases": [
"CVE-2023-3061"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-06-02T14:15:09Z",
"severity": "MODERATE"
},
"details": "A vulnerability was found in code-projects Agro-School Management System 1.0 and classified as critical. This issue affects some unknown processing of the file btn_functions.php of the component Attachment Image Handler. The manipulation leads to unrestricted upload. The attack may be initiated remotely. The associated identifier of this vulnerability is VDB-230567.",
"id": "GHSA-x3fj-vm97-72x4",
"modified": "2023-06-02T15:30:17Z",
"published": "2023-06-02T15:30:17Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-3061"
},
{
"type": "WEB",
"url": "https://github.com/hotencode/CveHub/blob/main/Agro-School%20Management%20System%20has%20a%20file%20upload%20(RCE)%20vulnerability.pdf"
},
{
"type": "WEB",
"url": "https://vuldb.com/?ctiid.230567"
},
{
"type": "WEB",
"url": "https://vuldb.com/?id.230567"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L",
"type": "CVSS_V3"
}
]
}
GHSA-X3H8-2MVF-VV78
Vulnerability from github – Published: 2025-11-05 17:48 – Updated: 2025-11-05 17:48A vulnerability in the web UI of Cisco Unified CCX could allow an authenticated, remote attacker to upload and execute arbitrary files.
This vulnerability is due to an insufficient input validation associated to file upload mechanisms. An attacker could exploit this vulnerability by uploading a malicious file to the web UI and executing it. A successful exploit could allow the attacker to execute arbitrary commands on the underlying system and elevate privileges to root. To exploit this vulnerability, the attacker must have valid administrative credentials.
{
"affected": [],
"aliases": [
"CVE-2025-20376"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-11-05T17:15:38Z",
"severity": "MODERATE"
},
"details": "A vulnerability in the web UI of Cisco Unified CCX could allow an authenticated, remote attacker to upload and execute arbitrary files.\n\nThis vulnerability is due to an insufficient input validation associated to file upload mechanisms. An attacker could exploit this vulnerability by uploading a malicious file to the web UI and executing it. A successful exploit could allow the attacker to execute arbitrary commands on the underlying system and elevate privileges to root. To exploit this vulnerability, the attacker must have valid administrative credentials.",
"id": "GHSA-x3h8-2mvf-vv78",
"modified": "2025-11-05T17:48:29Z",
"published": "2025-11-05T17:48:29Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-20376"
},
{
"type": "WEB",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cc-mult-vuln-gK4TFXSn"
}
],
"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:N",
"type": "CVSS_V3"
}
]
}
GHSA-X3J2-WMXH-24C7
Vulnerability from github – Published: 2022-07-16 00:00 – Updated: 2022-07-23 00:00A vulnerability was found in URVE Web Manager. It has been rated as critical. This issue affects some unknown processing of the file _internal/uploader.php. The manipulation leads to unrestricted upload. The attack needs to be approached within the local network. The exploit has been disclosed to the public and may be used.
{
"affected": [],
"aliases": [
"CVE-2022-2420"
],
"database_specific": {
"cwe_ids": [
"CWE-434"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2022-07-15T06:15:00Z",
"severity": "HIGH"
},
"details": "A vulnerability was found in URVE Web Manager. It has been rated as critical. This issue affects some unknown processing of the file _internal/uploader.php. The manipulation leads to unrestricted upload. The attack needs to be approached within the local network. The exploit has been disclosed to the public and may be used.",
"id": "GHSA-x3j2-wmxh-24c7",
"modified": "2022-07-23T00:00:21Z",
"published": "2022-07-16T00:00:31Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-2420"
},
{
"type": "WEB",
"url": "https://github.com/joinia/webray.com.cn/blob/main/URVE/URVE%20Web%20Manager%20uploader.php%20%20File%20upload%20vulnerability.md"
},
{
"type": "WEB",
"url": "https://vuldb.com/?id.203903"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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.