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.
13049 vulnerabilities reference this CWE, most recent first.
GHSA-9MV7-3C64-MMQW
Vulnerability from github – Published: 2025-09-10 20:44 – Updated: 2025-09-29 14:03Impact
When generating PDF files, this vulnerability allows an attacker to read arbitrary files from the filesystem by injecting malicious link element into the prepped RFCXML.
Workarounds
Test untrusted input with link elements with rel="attachment" before processing.
References
This is related to GHSA-cfmv-h8fx-85m7.
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "xml2rfc"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "3.30.2"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2025-11059"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": true,
"github_reviewed_at": "2025-09-10T20:44:58Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"details": "### Impact\n\nWhen generating PDF files, this vulnerability allows an attacker to read arbitrary files from the filesystem by injecting malicious link element into the prepped RFCXML.\n\n### Workarounds\n\nTest untrusted input with `link` elements with `rel=\"attachment\"` before processing.\n\n### References\nThis is related to [GHSA-cfmv-h8fx-85m7](https://github.com/ietf-tools/xml2rfc/security/advisories/GHSA-cfmv-h8fx-85m7).",
"id": "GHSA-9mv7-3c64-mmqw",
"modified": "2025-09-29T14:03:39Z",
"published": "2025-09-10T20:44:58Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/ietf-tools/xml2rfc/security/advisories/GHSA-9mv7-3c64-mmqw"
},
{
"type": "WEB",
"url": "https://github.com/ietf-tools/xml2rfc/commit/73fb1c91fc62ac540bb6bd24f982f2becf84c1b0"
},
{
"type": "PACKAGE",
"url": "https://github.com/ietf-tools/xml2rfc"
},
{
"type": "WEB",
"url": "https://github.com/ietf-tools/xml2rfc/releases/tag/v3.30.2"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "xml2rfc is vulnerable to arbitrary file reads through prepped files"
}
GHSA-9MV8-JQQ2-5M57
Vulnerability from github – Published: 2024-08-02 12:31 – Updated: 2024-08-02 12:31Digiwin EasyFlow .NET lacks proper access control for specific functionality, and the functionality do not adequately filter user input. A remote attacker with regular privilege can exploit this vulnerability to download arbitrary files from the remote server .
{
"affected": [],
"aliases": [
"CVE-2024-7323"
],
"database_specific": {
"cwe_ids": [
"CWE-22",
"CWE-36"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-08-02T11:16:44Z",
"severity": "MODERATE"
},
"details": "Digiwin EasyFlow .NET lacks proper access control for specific functionality, and the functionality do not adequately filter user input. A remote attacker with regular privilege can exploit this vulnerability to download arbitrary files from the remote server .",
"id": "GHSA-9mv8-jqq2-5m57",
"modified": "2024-08-02T12:31:44Z",
"published": "2024-08-02T12:31:44Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-7323"
},
{
"type": "WEB",
"url": "https://www.twcert.org.tw/en/cp-139-7990-87183-2.html"
},
{
"type": "WEB",
"url": "https://www.twcert.org.tw/tw/cp-132-7989-9c4ea-1.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-9MVW-CQG2-V8J4
Vulnerability from github – Published: 2022-05-17 04:15 – Updated: 2022-05-17 04:15Directory traversal vulnerability in the Speed Root Explorer application before 3.2 for Android and the Speed Explorer application before 2.2 for Android allows remote attackers to write to arbitrary files via a crafted filename.
{
"affected": [],
"aliases": [
"CVE-2014-9282"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2015-02-24T20:59:00Z",
"severity": "MODERATE"
},
"details": "Directory traversal vulnerability in the Speed Root Explorer application before 3.2 for Android and the Speed Explorer application before 2.2 for Android allows remote attackers to write to arbitrary files via a crafted filename.",
"id": "GHSA-9mvw-cqg2-v8j4",
"modified": "2022-05-17T04:15:18Z",
"published": "2022-05-17T04:15:18Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2014-9282"
},
{
"type": "WEB",
"url": "http://jvn.jp/en/jp/JVN42768331/index.html"
},
{
"type": "WEB",
"url": "http://jvndb.jvn.jp/jvndb/JVNDB-2015-000023"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-9MWJ-265R-F2GR
Vulnerability from github – Published: 2022-05-17 03:46 – Updated: 2025-04-12 12:48Directory traversal vulnerability in UploadServlet in the Remote Management component in Novell ZENworks Configuration Management (ZCM) 10 before 10.3 allows remote attackers to execute arbitrary code via a zenworks-fileupload request with a crafted directory name in the type parameter, in conjunction with a WAR filename in the filename parameter and WAR content in the POST data, a different vulnerability than CVE-2010-5323.
{
"affected": [],
"aliases": [
"CVE-2010-5324"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2015-06-07T23:59:00Z",
"severity": "HIGH"
},
"details": "Directory traversal vulnerability in UploadServlet in the Remote Management component in Novell ZENworks Configuration Management (ZCM) 10 before 10.3 allows remote attackers to execute arbitrary code via a zenworks-fileupload request with a crafted directory name in the type parameter, in conjunction with a WAR filename in the filename parameter and WAR content in the POST data, a different vulnerability than CVE-2010-5323.",
"id": "GHSA-9mwj-265r-f2gr",
"modified": "2025-04-12T12:48:30Z",
"published": "2022-05-17T03:46:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2010-5324"
},
{
"type": "WEB",
"url": "https://bugzilla.novell.com/show_bug.cgi?id=578911"
},
{
"type": "WEB",
"url": "https://www.novell.com/support/kb/doc.php?id=7005573"
},
{
"type": "WEB",
"url": "http://tucanalamigo.blogspot.com/2010/04/pdc-de-zdi-10-078.html"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/39114"
},
{
"type": "WEB",
"url": "http://www.zerodayinitiative.com/advisories/ZDI-10-078"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-9MX9-XF85-M8V5
Vulnerability from github – Published: 2025-04-24 09:30 – Updated: 2026-04-08 21:33The WPMasterToolKit (WPMTK) – All in one plugin plugin for WordPress is vulnerable to Directory Traversal in all versions up to, and including, 2.5.2. This makes it possible for authenticated attackers, with Administrator-level access and above, to read and modify the contents of arbitrary files on the server, which can contain sensitive information.
{
"affected": [],
"aliases": [
"CVE-2025-3300"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-04-24T09:15:31Z",
"severity": "HIGH"
},
"details": "The WPMasterToolKit (WPMTK) \u2013 All in one plugin plugin for WordPress is vulnerable to Directory Traversal in all versions up to, and including, 2.5.2. This makes it possible for authenticated attackers, with Administrator-level access and above, to read and modify the contents of arbitrary files on the server, which can contain sensitive information.",
"id": "GHSA-9mx9-xf85-m8v5",
"modified": "2026-04-08T21:33:04Z",
"published": "2025-04-24T09:30:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-3300"
},
{
"type": "WEB",
"url": "https://plugins.trac.wordpress.org/changeset?sfp_email=\u0026sfph_mail=\u0026reponame=\u0026old=3281127%40wpmastertoolkit\u0026new=3281127%40wpmastertoolkit\u0026sfp_email=\u0026sfph_mail="
},
{
"type": "WEB",
"url": "https://wordpress.org/plugins/wpmastertoolkit"
},
{
"type": "WEB",
"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/c389ba1a-45c5-4fba-9b99-0713fe39da42?source=cve"
}
],
"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-9P22-639X-GHP4
Vulnerability from github – Published: 2026-07-10 06:31 – Updated: 2026-07-10 06:31A vulnerability was identified in halo-dev halo up to 2.24.2. This affects the function ThemeUtils.unzipThemeTo of the file ThemeUtils.java of the component Theme Installation. Such manipulation of the argument metadata.name leads to path traversal. The attack may be launched remotely. The exploit is publicly available and might be used. The project closed the issue as "duplicate" but did not reference any other issue, report, or CVE.
{
"affected": [],
"aliases": [
"CVE-2026-15326"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-10T04:17:48Z",
"severity": "LOW"
},
"details": "A vulnerability was identified in halo-dev halo up to 2.24.2. This affects the function ThemeUtils.unzipThemeTo of the file ThemeUtils.java of the component Theme Installation. Such manipulation of the argument metadata.name leads to path traversal. The attack may be launched remotely. The exploit is publicly available and might be used. The project closed the issue as \"duplicate\" but did not reference any other issue, report, or CVE.",
"id": "GHSA-9p22-639x-ghp4",
"modified": "2026-07-10T06:31:20Z",
"published": "2026-07-10T06:31:20Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-15326"
},
{
"type": "WEB",
"url": "https://github.com/halo-dev/halo/issues/10062"
},
{
"type": "WEB",
"url": "https://github.com/halo-dev/halo"
},
{
"type": "WEB",
"url": "https://vuldb.com/cve/CVE-2026-15326"
},
{
"type": "WEB",
"url": "https://vuldb.com/submit/853064"
},
{
"type": "WEB",
"url": "https://vuldb.com/vuln/377265"
},
{
"type": "WEB",
"url": "https://vuldb.com/vuln/377265/cti"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:L",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/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-9P2M-FGH4-J2HW
Vulnerability from github – Published: 2022-05-24 17:21 – Updated: 2023-01-27 18:30Zyxel Armor X1 WAP6806 1.00(ABAL.6)C0 devices allow Directory Traversal via the images/eaZy/ URI.
{
"affected": [],
"aliases": [
"CVE-2020-14461"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2020-06-22T13:15:00Z",
"severity": "MODERATE"
},
"details": "Zyxel Armor X1 WAP6806 1.00(ABAL.6)C0 devices allow Directory Traversal via the images/eaZy/ URI.",
"id": "GHSA-9p2m-fgh4-j2hw",
"modified": "2023-01-27T18:30:33Z",
"published": "2022-05-24T17:21:24Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2020-14461"
},
{
"type": "WEB",
"url": "https://cxsecurity.com/issue/WLB-2020060088"
},
{
"type": "WEB",
"url": "http://packetstormsecurity.com/files/158428/Zyxel-Armor-X1-WAP6806-Directory-Traversal.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-9P3J-JG4G-2MX3
Vulnerability from github – Published: 2022-05-02 03:56 – Updated: 2022-05-02 03:56Directory traversal vulnerability in menu.php in phpNagios 1.2.0 allows remote attackers to include and execute arbitrary local files via directory traversal sequences in the conf[lang] parameter.
{
"affected": [],
"aliases": [
"CVE-2009-4626"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2010-01-18T20:30:00Z",
"severity": "HIGH"
},
"details": "Directory traversal vulnerability in menu.php in phpNagios 1.2.0 allows remote attackers to include and execute arbitrary local files via directory traversal sequences in the conf[lang] parameter.",
"id": "GHSA-9p3j-jg4g-2mx3",
"modified": "2022-05-02T03:56:34Z",
"published": "2022-05-02T03:56:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2009-4626"
},
{
"type": "WEB",
"url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/53119"
},
{
"type": "WEB",
"url": "http://www.exploit-db.com/exploits/9611"
},
{
"type": "WEB",
"url": "http://www.vupen.com/english/advisories/2009/2615"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-9P3P-W5JF-8XXG
Vulnerability from github – Published: 2025-05-13 20:02 – Updated: 2025-05-13 20:02TL;DR
This vulnerability affects all Kirby setups that use PHP's built-in server. Such setups are commonly only used during local development.
Sites that use other server software (such as Apache, nginx or Caddy) are not affected.
Introduction
For use with PHP's built-in web server, Kirby provides a router.php file. The router delegates requests to static files to PHP so that assets and other static files in the document root can be accessed by the browser.
This logic was vulnerable against path traversal attacks. By using special elements such as .. and / separators, attackers can escape outside of the restricted location to access files or directories that are elsewhere on the system. One of the most common special elements is the ../ sequence, which in most modern operating systems is interpreted as the parent directory of the current location.
Impact
The missing path traversal check allowed attackers to navigate all files on the server that were accessible to the PHP process, including files outside of the Kirby installation.
The vulnerable implementation delegated all existing files to PHP, including existing files outside of the document root. This leads to a different response that allows attackers to determine whether the requested file exists.
Because Kirby's router only delegates such requests to PHP and does not load or execute them, contents of the files were not exposed as PHP treats requests to files outside of the document root as invalid.
Patches
The problem has been patched in Kirby 3.9.8.3, Kirby 3.10.1.2 and Kirby 4.7.1. Please update to one of these or a later version to fix the vulnerability.
In all of the mentioned releases, we have updated the router to check if existing static files are within the document root. Requests to files outside the document root are treated as page requests of the error page and will no longer allow to determine whether the file exists or not.
{
"affected": [
{
"package": {
"ecosystem": "Packagist",
"name": "getkirby/cms"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "3.9.8.3"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "getkirby/cms"
},
"ranges": [
{
"events": [
{
"introduced": "3.10.0"
},
{
"fixed": "3.10.1.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "Packagist",
"name": "getkirby/cms"
},
"ranges": [
{
"events": [
{
"introduced": "4.0.0"
},
{
"fixed": "4.7.1"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2025-30207"
],
"database_specific": {
"cwe_ids": [
"CWE-22",
"CWE-23"
],
"github_reviewed": true,
"github_reviewed_at": "2025-05-13T20:02:20Z",
"nvd_published_at": "2025-05-13T16:15:29Z",
"severity": "LOW"
},
"details": "### TL;DR\n\nThis vulnerability affects all Kirby setups that use PHP\u0027s built-in server. Such setups are commonly only used during local development.\n\nSites that use other server software (such as Apache, nginx or Caddy) are *not* affected.\n\n----\n\n### Introduction\n\nFor use with PHP\u0027s built-in web server, Kirby provides a `router.php` file. The router delegates requests to static files to PHP so that assets and other static files in the document root can be accessed by the browser.\n\nThis logic was vulnerable against path traversal attacks. By using special elements such as `..` and `/` separators, attackers can escape outside of the restricted location to access files or directories that are elsewhere on the system. One of the most common special elements is the `../` sequence, which in most modern operating systems is interpreted as the parent directory of the current location.\n\n### Impact\n\nThe missing path traversal check allowed attackers to navigate all files on the server that were accessible to the PHP process, including files outside of the Kirby installation.\n\nThe vulnerable implementation delegated all existing files to PHP, including existing files outside of the document root. This leads to a different response that allows attackers to determine whether the requested file exists.\n\nBecause Kirby\u0027s router only delegates such requests to PHP and does not load or execute them, contents of the files were not exposed as PHP treats requests to files outside of the document root as invalid.\n\n### Patches\n\nThe problem has been patched in [Kirby 3.9.8.3](https://github.com/getkirby/kirby/releases/tag/3.9.8.3), [Kirby 3.10.1.2](https://github.com/getkirby/kirby/releases/tag/3.10.1.2) and [Kirby 4.7.1](https://github.com/getkirby/kirby/releases/tag/4.7.1). Please update to one of these or a [later version](https://github.com/getkirby/kirby/releases) to fix the vulnerability.\n\nIn all of the mentioned releases, we have updated the router to check if existing static files are within the document root. Requests to files outside the document root are treated as page requests of the error page and will no longer allow to determine whether the file exists or not.",
"id": "GHSA-9p3p-w5jf-8xxg",
"modified": "2025-05-13T20:02:20Z",
"published": "2025-05-13T20:02:20Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/getkirby/kirby/security/advisories/GHSA-9p3p-w5jf-8xxg"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-30207"
},
{
"type": "WEB",
"url": "https://github.com/getkirby/kirby/commit/3ebc9ad3f5adcbd4838ce60219f1c9a561231235"
},
{
"type": "PACKAGE",
"url": "https://github.com/getkirby/kirby"
},
{
"type": "WEB",
"url": "https://github.com/getkirby/kirby/releases/tag/3.10.1.2"
},
{
"type": "WEB",
"url": "https://github.com/getkirby/kirby/releases/tag/3.9.8.3"
},
{
"type": "WEB",
"url": "https://github.com/getkirby/kirby/releases/tag/4.7.1"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Kirby vulnerable to path traversal in the router for PHP\u0027s built-in server"
}
GHSA-9P3W-RM2Q-9GXC
Vulnerability from github – Published: 2026-03-26 21:31 – Updated: 2026-05-19 15:31A malicious SCP server can send unexpected paths that could make the client application override local files outside of working directory. This could be misused to create malicious executable or configuration files and make the user execute them under specific consequences.
This is the same issue as in OpenSSH, tracked as CVE-2019-6111.
{
"affected": [],
"aliases": [
"CVE-2026-0964"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-03-26T21:17:00Z",
"severity": "MODERATE"
},
"details": "A malicious SCP server can send unexpected paths that could make the\nclient application override local files outside of working directory.\nThis could be misused to create malicious executable or configuration\nfiles and make the user execute them under specific consequences.\n\nThis is the same issue as in OpenSSH, tracked as CVE-2019-6111.",
"id": "GHSA-9p3w-rm2q-9gxc",
"modified": "2026-05-19T15:31:19Z",
"published": "2026-03-26T21:31:27Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-0964"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:18160"
},
{
"type": "WEB",
"url": "https://access.redhat.com/errata/RHSA-2026:18683"
},
{
"type": "WEB",
"url": "https://access.redhat.com/security/cve/CVE-2026-0964"
},
{
"type": "WEB",
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2436979"
},
{
"type": "WEB",
"url": "https://www.libssh.org/2026/02/10/libssh-0-12-0-and-0-11-4-security-releases"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L",
"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.