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.
15153 vulnerabilities reference this CWE, most recent first.
GHSA-J3Q3-9JVF-VRW4
Vulnerability from github – Published: 2022-05-02 03:47 – Updated: 2022-05-02 03:47Multiple absolute path traversal vulnerabilities in PHP-Calendar 1.1 allow remote attackers to include and execute arbitrary local files via a full pathname in the configfile parameter to (1) update08.php or (2) update10.php. NOTE: in some environments, this can be leveraged for remote file inclusion by using a UNC share pathname or an ftp, ftps, or ssh2.sftp URL.
{
"affected": [],
"aliases": [
"CVE-2009-3702"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2009-12-22T19:30:00Z",
"severity": "HIGH"
},
"details": "Multiple absolute path traversal vulnerabilities in PHP-Calendar 1.1 allow remote attackers to include and execute arbitrary local files via a full pathname in the configfile parameter to (1) update08.php or (2) update10.php. NOTE: in some environments, this can be leveraged for remote file inclusion by using a UNC share pathname or an ftp, ftps, or ssh2.sftp URL.",
"id": "GHSA-j3q3-9jvf-vrw4",
"modified": "2022-05-02T03:47:46Z",
"published": "2022-05-02T03:47:46Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2009-3702"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/archive/1/508548/100/0/threaded"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-J3R3-FQF7-GC2R
Vulnerability from github – Published: 2026-09-29 18:31 – Updated: 2026-10-06 18:31Joomla Extension - balbooa.com - Unauthenticated path traversal exfiltrates local files through auto-reply attachments in Balbooa Forms < 2.4.3.4 - Balbooa Forms accepts upload-field state as Guest-controlled JSON during public form submission. For every object whose id merely looks numeric, the component trusts the supplied filename, concatenates it below the configured upload directory, and adds the result to an array of local attachment paths. It does not load the referenced attachment row, verify ownership/session/form/field, require that the ID exists, canonicalize the path, or enforce containment. If the form's normal “auto reply” and “attach uploaded files” options are enabled, the component sends those local paths as email attachments to the address submitted in an email field. A Guest can therefore submit a nonexistent numeric ID plus a traversal filename such as ../../../../configuration.php and receive any file readable by the Joomla process.
{
"affected": [],
"aliases": [
"CVE-2026-102424"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-29T17:17:06Z",
"severity": "HIGH"
},
"details": "Joomla Extension - balbooa.com - Unauthenticated path traversal exfiltrates local files through auto-reply attachments in Balbooa Forms \u003c 2.4.3.4 - Balbooa Forms accepts upload-field state as Guest-controlled JSON during public form submission. For every object whose `id` merely looks numeric, the component trusts the supplied `filename`, concatenates it below the configured upload directory, and adds the result to an array of local attachment paths. It does not load the referenced attachment row, verify ownership/session/form/field, require that the ID exists, canonicalize the path, or enforce containment. If the form\u0027s normal \u201cauto reply\u201d and \u201cattach uploaded files\u201d options are enabled, the component sends those local paths as email attachments to the address submitted in an email field. A Guest can therefore submit a nonexistent numeric ID plus a traversal filename such as `../../../../configuration.php` and receive any file readable by the Joomla process.",
"id": "GHSA-j3r3-fqf7-gc2r",
"modified": "2026-10-06T18:31:21Z",
"published": "2026-09-29T18:31:48Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-102424"
},
{
"type": "WEB",
"url": "https://www.balbooa.com"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/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-J3VP-3P2J-8Q53
Vulnerability from github – Published: 2024-12-10 06:31 – Updated: 2024-12-10 18:31The System Dashboard WordPress plugin before 2.8.15 does not validate user input used in a path, which could allow high privilege users such as admin to perform path traversal attacks an read arbitrary files on the server
{
"affected": [],
"aliases": [
"CVE-2024-10708"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-12-10T06:15:20Z",
"severity": "MODERATE"
},
"details": "The System Dashboard WordPress plugin before 2.8.15 does not validate user input used in a path, which could allow high privilege users such as admin to perform path traversal attacks an read arbitrary files on the server",
"id": "GHSA-j3vp-3p2j-8q53",
"modified": "2024-12-10T18:31:06Z",
"published": "2024-12-10T06:31:40Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-10708"
},
{
"type": "WEB",
"url": "https://wpscan.com/vulnerability/61d750a5-8c2c-4c94-a1a9-6a254c2a0d03"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-J3VX-7XGH-Q759
Vulnerability from github – Published: 2026-07-10 15:31 – Updated: 2026-07-10 15:31phpMyFAQ before 4.1.5 contains a potential authenticated path traversal vulnerability in the concatenatePaths() function within src/phpMyFAQ/Export/Pdf/Wrapper.php. A user with FAQ editing privileges can store HTML containing crafted image paths that are processed during PDF generation. The path resolution logic locates the substring "content" within a user-controlled path using strpos(); when "content" is absent, strpos() returns false, which becomes 0 when cast to an integer, preserving the entire attacker-controlled path. This path is later passed to file_get_contents() without canonicalization or root-directory containment validation, which may allow reading of files outside the intended content directory.
{
"affected": [],
"aliases": [
"CVE-2026-57961"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-10T15:16:47Z",
"severity": "MODERATE"
},
"details": "phpMyFAQ before 4.1.5 contains a potential authenticated path traversal vulnerability in the concatenatePaths() function within src/phpMyFAQ/Export/Pdf/Wrapper.php. A user with FAQ editing privileges can store HTML containing crafted image paths that are processed during PDF generation. The path resolution logic locates the substring \"content\" within a user-controlled path using strpos(); when \"content\" is absent, strpos() returns false, which becomes 0 when cast to an integer, preserving the entire attacker-controlled path. This path is later passed to file_get_contents() without canonicalization or root-directory containment validation, which may allow reading of files outside the intended content directory.",
"id": "GHSA-j3vx-7xgh-q759",
"modified": "2026-07-10T15:31:40Z",
"published": "2026-07-10T15:31:40Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/thorsten/phpMyFAQ/security/advisories/GHSA-88g4-74f3-63x9"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-57961"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/phpmyfaq-authenticated-path-traversal-in-pdf-export-via-concatenatepaths-function"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-J3W9-V397-F6WG
Vulnerability from github – Published: 2023-12-15 09:30 – Updated: 2023-12-15 09:30Multisuns EasyLog web+ has a path traversal vulnerability within its parameter in a specific URL. An unauthenticated remote attacker can exploit this vulnerability to bypass authentication and download arbitrary system files.
{
"affected": [],
"aliases": [
"CVE-2023-48389"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-12-15T09:15:08Z",
"severity": "HIGH"
},
"details": "Multisuns EasyLog web+ has a path traversal vulnerability within its parameter in a specific URL. An unauthenticated remote attacker can exploit this vulnerability to bypass authentication and download arbitrary system files.",
"id": "GHSA-j3w9-v397-f6wg",
"modified": "2023-12-15T09:30:18Z",
"published": "2023-12-15T09:30:18Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-48389"
},
{
"type": "WEB",
"url": "https://www.twcert.org.tw/tw/cp-132-7604-ab0fd-1.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-J3X3-RC9W-WF4M
Vulnerability from github – Published: 2026-04-14 18:30 – Updated: 2026-04-14 18:30A improper limitation of a pathname to a restricted directory ('path traversal') vulnerability in Fortinet FortiSandbox 5.0.0 through 5.0.5, FortiSandbox 4.4.0 through 4.4.8, FortiSandbox 4.2 all versions, FortiSandbox Cloud 5.0.4, FortiSandbox PaaS 5.0.4 may allow a privileged attacker with super-admin profile and CLI access to delete an arbitrary directory via HTTP crafted requests.
{
"affected": [],
"aliases": [
"CVE-2026-25691"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-04-14T16:16:37Z",
"severity": "MODERATE"
},
"details": "A improper limitation of a pathname to a restricted directory (\u0027path traversal\u0027) vulnerability in Fortinet FortiSandbox 5.0.0 through 5.0.5, FortiSandbox 4.4.0 through 4.4.8, FortiSandbox 4.2 all versions, FortiSandbox Cloud 5.0.4, FortiSandbox PaaS 5.0.4 may allow a privileged attacker with super-admin profile and CLI access to delete an arbitrary directory via HTTP crafted requests.",
"id": "GHSA-j3x3-rc9w-wf4m",
"modified": "2026-04-14T18:30:35Z",
"published": "2026-04-14T18:30:35Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-25691"
},
{
"type": "WEB",
"url": "https://fortiguard.fortinet.com/psirt/FG-IR-26-115"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-J3X6-F97G-2Q47
Vulnerability from github – Published: 2026-08-14 21:31 – Updated: 2026-08-14 21:31IBM Db2 Mirror for i 7.4, 7.5, and 7.6 could allow a remote attacker to write files to arbitrary locations due to path traversal.
{
"affected": [],
"aliases": [
"CVE-2026-17181"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-14T20:16:50Z",
"severity": "CRITICAL"
},
"details": "IBM Db2 Mirror for i 7.4, 7.5, and 7.6 could allow a remote attacker to write files to arbitrary locations due to path traversal.",
"id": "GHSA-j3x6-f97g-2q47",
"modified": "2026-08-14T21:31:35Z",
"published": "2026-08-14T21:31:35Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-17181"
},
{
"type": "WEB",
"url": "https://www.ibm.com/support/pages/node/7283359"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:L",
"type": "CVSS_V3"
}
]
}
GHSA-J3XQ-FV5R-JFGV
Vulnerability from github – Published: 2022-05-14 01:45 – Updated: 2022-05-14 01:45app/plug/attachment/controller/admincontroller.php in SDCMS 1.6 allows reading arbitrary files via a /?m=plug&c=admin&a=index&p=attachment&root= directory traversal. The value of the root parameter must be base64 encoded (note that base64 encoding, instead of URL encoding, is very rare in a directory traversal attack vector).
{
"affected": [],
"aliases": [
"CVE-2018-19748"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2018-11-29T21:29:00Z",
"severity": "HIGH"
},
"details": "app/plug/attachment/controller/admincontroller.php in SDCMS 1.6 allows reading arbitrary files via a /?m=plug\u0026c=admin\u0026a=index\u0026p=attachment\u0026root= directory traversal. The value of the root parameter must be base64 encoded (note that base64 encoding, instead of URL encoding, is very rare in a directory traversal attack vector).",
"id": "GHSA-j3xq-fv5r-jfgv",
"modified": "2022-05-14T01:45:55Z",
"published": "2022-05-14T01:45:55Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2018-19748"
},
{
"type": "WEB",
"url": "https://blog.whiterabbitxyj.com/cve/SDCMS_1.6_directory_traversal.doc"
},
{
"type": "WEB",
"url": "https://github.com/WhiteRabbitc/WhiteRabbitc.github.io/blob/master/cve/SDCMS_1.6_directory_traversal.doc"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-J422-QMXP-HV94
Vulnerability from github – Published: 2025-12-02 00:38 – Updated: 2025-12-02 00:38Summary
A path traversal vulnerability has been identified in Grav CMS, versions 1.7.49.5 , allowing authenticated attackers
with administrative privileges to read arbitrary files on the underlying server filesystem. This vulnerability arises due
to insufficient input sanitization in the backup tool, where user-supplied paths are not properly restricted, enabling
access to files outside the intended webroot directory. The impact of this vulnerability depends on the privileges of
the user account running the application.
PoC
To accurately demonstrate the maximum potential impact of this vulnerability, the testing environment was configured in a specific way:
- Elevated Privileges: The application was run locally with the highest possible system privileges, operating under the **`root`** user account.
- Objective: This configuration was chosen to unequivocally show that the path traversal vulnerability is not just a theoretical issue but can lead to a complete compromise of the underlying host when combined with poor operational practices. The ability to read any file on the system is the ultimate test of the flaw's severity.
Proof of Concept Goal: Under these conditions, the subsequent PoC will exploit the vulnerability to read the SSH private key
of the `root` user (`/root/.ssh/id_rsa`). The successful exfiltration of this key represents a worst-case scenario, as it would provide
an attacker with persistent, undetectable, and complete administrative access to the host server. This highlights the critical intersection
of an application-layer vulnerability and a infrastructure-level misconfiguration.
1- LOGIN AS ADMIN AND GO TO : http://127.0.0.1/admin/tools/backups
2- Change 'Root Folder' to backup directory /../../../../../../../root/.ssh/
3- CLICK : 'SAVE'
4- CLICK : 'Backup Now'
5- Extract Backup :
{
"affected": [
{
"package": {
"ecosystem": "Packagist",
"name": "getgrav/grav"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.8.0-beta.27"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2025-66302"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": true,
"github_reviewed_at": "2025-12-02T00:38:41Z",
"nvd_published_at": "2025-12-01T22:15:49Z",
"severity": "MODERATE"
},
"details": "### Summary\n```\nA path traversal vulnerability has been identified in Grav CMS, versions 1.7.49.5 , allowing authenticated attackers\n with administrative privileges to read arbitrary files on the underlying server filesystem. This vulnerability arises due\n to insufficient input sanitization in the backup tool, where user-supplied paths are not properly restricted, enabling\n access to files outside the intended webroot directory. The impact of this vulnerability depends on the privileges of \nthe user account running the application.\n```\n\n### PoC\n```\nTo accurately demonstrate the maximum potential impact of this vulnerability, the testing environment was configured in a specific way:\n\n- Elevated Privileges: The application was run locally with the highest possible system privileges, operating under the **`root`** user account.\n \n- Objective: This configuration was chosen to unequivocally show that the path traversal vulnerability is not just a theoretical issue but can lead to a complete compromise of the underlying host when combined with poor operational practices. The ability to read any file on the system is the ultimate test of the flaw\u0027s severity.\n \n\nProof of Concept Goal: Under these conditions, the subsequent PoC will exploit the vulnerability to read the SSH private key\n of the `root` user (`/root/.ssh/id_rsa`). The successful exfiltration of this key represents a worst-case scenario, as it would provide \nan attacker with persistent, undetectable, and complete administrative access to the host server. This highlights the critical intersection\n of an application-layer vulnerability and a infrastructure-level misconfiguration.\n\n```\n\n\n\n\n```\n1- LOGIN AS ADMIN AND GO TO : http://127.0.0.1/admin/tools/backups\n2- Change \u0027Root Folder\u0027 to backup directory /../../../../../../../root/.ssh/ \n\n```\n\u003cimg width=\"1902\" height=\"492\" alt=\"Screenshot 2025-09-11 161519\" src=\"https://github.com/user-attachments/assets/23a60dc3-7758-4e24-b910-e66a1dd1f5e2\" /\u003e\n\n\n\n```\n3- CLICK : \u0027SAVE\u0027\n4- CLICK : \u0027Backup Now\u0027\n```\n\n\u003cimg width=\"1916\" height=\"512\" alt=\"Screenshot 2025-09-11 154151\" src=\"https://github.com/user-attachments/assets/88a63ff2-777e-467e-857b-0644ef698499\" /\u003e\n\n```\n5- Extract Backup :\n```\n\n\n\u003cimg width=\"704\" height=\"101\" alt=\"Screenshot 2025-09-11 160114\" src=\"https://github.com/user-attachments/assets/b91ce4db-9843-4280-b8f0-32c73aa12d4d\" /\u003e\n\u003cimg width=\"567\" height=\"101\" alt=\"Screenshot 2025-09-11 160135\" src=\"https://github.com/user-attachments/assets/155ce7d8-c2fc-4b54-b054-f7c7550bec82\" /\u003e",
"id": "GHSA-j422-qmxp-hv94",
"modified": "2025-12-02T00:38:41Z",
"published": "2025-12-02T00:38:41Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/getgrav/grav/security/advisories/GHSA-j422-qmxp-hv94"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-66302"
},
{
"type": "WEB",
"url": "https://github.com/getgrav/grav/commit/ed640a13143c4177af013cf001969ed2c5e197ee"
},
{
"type": "PACKAGE",
"url": "https://github.com/getgrav/grav"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N",
"type": "CVSS_V3"
}
],
"summary": "Grav vulnerable to Path Traversal allowing server files backup"
}
GHSA-J42Q-G27M-825X
Vulnerability from github – Published: 2026-02-05 15:31 – Updated: 2026-02-05 15:31Path Traversal vulnerability in Digitek ADT1100 and Digitek DT950 from PRIMION DIGITEK, S.L.U (Azkoyen Group). This vulnerability allows an attacker to access arbitrary files in the server's file system, thet is, 'http:///..%2F..% 2F..%2F..%2F..%2F..%2F..%2F..%2F..%2Fetc%2Fpasswd'. By manipulating the input to include URL encoded directory traversal sequences (e.g., %2F representing /), an attacker can bypass the input validation mechanisms ans retrieve sensitive files outside the intended directory, which could lead to information disclosure or further system compromise.
{
"affected": [],
"aliases": [
"CVE-2026-1523"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-02-05T14:16:04Z",
"severity": "HIGH"
},
"details": "Path Traversal vulnerability in Digitek ADT1100 and Digitek DT950 from PRIMION DIGITEK, S.L.U (Azkoyen Group). This vulnerability allows an attacker to access arbitrary files in the server\u0027s file system, thet is, \u0027http://\u003chost\u003e/..%2F..% 2F..%2F..%2F..%2F..%2F..%2F..%2F..%2Fetc%2Fpasswd\u0027. By manipulating the input to include URL encoded directory traversal sequences (e.g., %2F representing /), an attacker can bypass the input validation mechanisms ans retrieve sensitive files outside the intended directory, which could lead to information disclosure or further system compromise.",
"id": "GHSA-j42q-g27m-825x",
"modified": "2026-02-05T15:31:14Z",
"published": "2026-02-05T15:31:14Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-1523"
},
{
"type": "WEB",
"url": "https://www.incibe.es/en/incibe-cert/notices/aviso/path-traversal-digitek-grupo-azkoyen"
}
],
"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/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 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.