CWE-73
AllowedExternal Control of File Name or Path
Abstraction: Base · Status: Draft
The product allows user input to control or influence paths or file names that are used in filesystem operations.
1263 vulnerabilities reference this CWE, most recent first.
GHSA-JV6V-FVVX-4932
Vulnerability from github – Published: 2020-06-03 21:58 – Updated: 2021-03-04 18:28Impact
An attacker can exploit this vulnerability to delete arbitrary local files of an October CMS server. The vulnerability is only exploitable by an authenticated backend user with the cms.manage_assets permission.
Patches
Issue has been patched in Build 466 (v1.0.466).
Workarounds
Apply https://github.com/octobercms/october/commit/2b8939cc8b5b6fe81e093fe2c9f883ada4e3c8cc to your installation manually if unable to upgrade to Build 466.
References
Reported by Sivanesh Ashok
For more information
If you have any questions or comments about this advisory: * Email us at hello@octobercms.com
Threat assessment:
{
"affected": [
{
"package": {
"ecosystem": "Packagist",
"name": "october/cms"
},
"ranges": [
{
"events": [
{
"introduced": "1.0.319"
},
{
"fixed": "1.0.466"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2020-5296"
],
"database_specific": {
"cwe_ids": [
"CWE-610",
"CWE-73"
],
"github_reviewed": true,
"github_reviewed_at": "2020-06-03T21:26:30Z",
"nvd_published_at": "2020-06-03T22:15:00Z",
"severity": "MODERATE"
},
"details": "### Impact\nAn attacker can exploit this vulnerability to delete arbitrary local files of an October CMS server. The vulnerability is only exploitable by an authenticated backend user with the `cms.manage_assets` permission.\n\n### Patches\nIssue has been patched in Build 466 (v1.0.466).\n\n### Workarounds\nApply https://github.com/octobercms/october/commit/2b8939cc8b5b6fe81e093fe2c9f883ada4e3c8cc to your installation manually if unable to upgrade to Build 466.\n\n### References\nReported by [Sivanesh Ashok](https://stazot.com/)\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Email us at [hello@octobercms.com](mailto:hello@octobercms.com)\n\n### Threat assessment:\n\u003cimg width=\"1241\" alt=\"Screen Shot 2020-03-31 at 12 16 53 PM\" src=\"https://user-images.githubusercontent.com/7253840/78060872-89354d00-7349-11ea-8c2b-5881b0a50736.png\"\u003e",
"id": "GHSA-jv6v-fvvx-4932",
"modified": "2021-03-04T18:28:29Z",
"published": "2020-06-03T21:58:21Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/octobercms/october/security/advisories/GHSA-jv6v-fvvx-4932"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2020-5296"
},
{
"type": "WEB",
"url": "https://github.com/octobercms/october/commit/2b8939cc8b5b6fe81e093fe2c9f883ada4e3c8cc"
},
{
"type": "WEB",
"url": "http://packetstormsecurity.com/files/158730/October-CMS-Build-465-XSS-File-Read-File-Deletion-CSV-Injection.html"
},
{
"type": "WEB",
"url": "http://seclists.org/fulldisclosure/2020/Aug/2"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:N/I:H/A:N",
"type": "CVSS_V3"
}
],
"summary": "Arbitrary File Deletion vulnerability in OctoberCMS"
}
GHSA-JW66-5J32-J2M2
Vulnerability from github – Published: 2026-09-03 15:32 – Updated: 2026-09-03 15:32DbGate fails to validate jslid parameters in the jsldata controller, allowing authenticated users to read and write arbitrary files via file:// scheme resolution. Attackers can exploit getJslFileName() to bypass directory containment and access sensitive files including encrypted database credentials stored in connections configuration.
{
"affected": [],
"aliases": [
"CVE-2026-85176"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-03T15:17:38Z",
"severity": "HIGH"
},
"details": "DbGate fails to validate jslid parameters in the jsldata controller, allowing authenticated users to read and write arbitrary files via file:// scheme resolution. Attackers can exploit getJslFileName() to bypass directory containment and access sensitive files including encrypted database credentials stored in connections configuration.",
"id": "GHSA-jw66-5j32-j2m2",
"modified": "2026-09-03T15:32:24Z",
"published": "2026-09-03T15:32:24Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-85176"
},
{
"type": "WEB",
"url": "https://github.com/dbgate/dbgate/issues/1502"
},
{
"type": "WEB",
"url": "https://github.com/dbgate/dbgate"
},
{
"type": "WEB",
"url": "https://github.com/dbgate/dbgate/blob/v7.2.6/packages/api/src/controllers/jsldata.js"
},
{
"type": "WEB",
"url": "https://github.com/dbgate/dbgate/blob/v7.2.6/packages/api/src/utility/getJslFileName.js"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/dbgate-through-7.2.6-arbitrary-file-read-and-write-via-file-jslid"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-JW7M-FMFJ-94V7
Vulnerability from github – Published: 2025-01-04 06:30 – Updated: 2025-01-04 06:30A vulnerability was found in TCS BaNCS 10. It has been classified as problematic. This affects an unknown part of the file /REPORTS/REPORTS_SHOW_FILE.jsp. The manipulation of the argument FilePath leads to file inclusion.
{
"affected": [],
"aliases": [
"CVE-2025-0202"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-01-04T05:15:07Z",
"severity": "MODERATE"
},
"details": "A vulnerability was found in TCS BaNCS 10. It has been classified as problematic. This affects an unknown part of the file /REPORTS/REPORTS_SHOW_FILE.jsp. The manipulation of the argument FilePath leads to file inclusion.",
"id": "GHSA-jw7m-fmfj-94v7",
"modified": "2025-01-04T06:30:32Z",
"published": "2025-01-04T06:30:32Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-0202"
},
{
"type": "WEB",
"url": "https://vuldb.com/?ctiid.290139"
},
{
"type": "WEB",
"url": "https://vuldb.com/?id.290139"
},
{
"type": "WEB",
"url": "https://vuldb.com/?submit.469455"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:A/AC:L/AT:N/PR:L/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"
}
]
}
GHSA-JWRC-3V3F-5CQ5
Vulnerability from github – Published: 2024-03-23 21:30 – Updated: 2025-01-24 20:18paddlepaddle/paddle 2.6.0 allows arbitrary file read via paddle.vision.ops.read_file.
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "paddlepaddle"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"last_affected": "2.6.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2024-1603"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": true,
"github_reviewed_at": "2024-03-25T19:37:34Z",
"nvd_published_at": "2024-03-23T19:15:07Z",
"severity": "HIGH"
},
"details": "paddlepaddle/paddle 2.6.0 allows arbitrary file read via paddle.vision.ops.read_file.",
"id": "GHSA-jwrc-3v3f-5cq5",
"modified": "2025-01-24T20:18:54Z",
"published": "2024-03-23T21:30:39Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-1603"
},
{
"type": "PACKAGE",
"url": "https://github.com/PaddlePaddle/Paddle"
},
{
"type": "WEB",
"url": "https://github.com/PaddlePaddle/Paddle/blob/release/2.6/python/paddle/vision/ops.py#L1262"
},
{
"type": "WEB",
"url": "https://github.com/PaddlePaddle/Paddle/blob/release/2.6/python/paddle/vision/ops.py#L1295-L1334"
},
{
"type": "WEB",
"url": "https://huntr.com/bounties/7739eced-73a3-4a96-afcd-9c753c55929e"
}
],
"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"
}
],
"summary": "PaddlePaddle allows arbitrary file read via paddle.vision.ops.read_file"
}
GHSA-JXCH-62JX-98VM
Vulnerability from github – Published: 2024-01-10 18:30 – Updated: 2025-11-04 21:31A local file inclusion vulnerability exists in the getLanguageFromBrowser functionality of WWBN AVideo dev master commit 15fed957fb. A specially crafted HTTP request can lead to arbitrary code execution. An attacker can send a series of HTTP requests to trigger this vulnerability.
{
"affected": [],
"aliases": [
"CVE-2023-47862"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-01-10T16:15:47Z",
"severity": "CRITICAL"
},
"details": "A local file inclusion vulnerability exists in the getLanguageFromBrowser functionality of WWBN AVideo dev master commit 15fed957fb. A specially crafted HTTP request can lead to arbitrary code execution. An attacker can send a series of HTTP requests to trigger this vulnerability.",
"id": "GHSA-jxch-62jx-98vm",
"modified": "2025-11-04T21:31:00Z",
"published": "2024-01-10T18:30:26Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-47862"
},
{
"type": "WEB",
"url": "https://talosintelligence.com/vulnerability_reports/TALOS-2023-1886"
},
{
"type": "WEB",
"url": "https://www.talosintelligence.com/vulnerability_reports/TALOS-2023-1886"
}
],
"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-JXCR-W9Q6-GMHX
Vulnerability from github – Published: 2026-06-30 15:30 – Updated: 2026-07-02 18:36Arbitrary File Read (Unauthenticated) in NetScaler ADC and NetScaler Gateway if the access to NSIP, Cluster Management IP or SNIP with management access is enabled
{
"affected": [],
"aliases": [
"CVE-2026-10816"
],
"database_specific": {
"cwe_ids": [
"CWE-610",
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-06-30T13:17:04Z",
"severity": "HIGH"
},
"details": "Arbitrary File Read (Unauthenticated) in\u00a0NetScaler ADC and NetScaler Gateway if the access to NSIP, Cluster Management IP or SNIP with management access is enabled",
"id": "GHSA-jxcr-w9q6-gmhx",
"modified": "2026-07-02T18:36:17Z",
"published": "2026-06-30T15:30:44Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-10816"
},
{
"type": "WEB",
"url": "https://support.citrix.com/support-home/kbsearch/article?articleNumber=CTX696604"
}
],
"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:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-M382-6JW4-FMP6
Vulnerability from github – Published: 2026-10-07 20:26 – Updated: 2026-10-07 20:26Impact
A vulnerability in how Ghost loads theme translation files allowed an authenticated Administrator to read JSON files outside of the active theme's directory, potentially exposing server configuration secrets.
Vulnerable versions
This vulnerability is present in Ghost from v1.20.0 up to v6.64.0.
Patches
v6.64.0 contains a fix for this issue.
How to update
For self-hosters using Docker, find Docker's official Ghost image here. Updating a Docker-based Ghost instance is documented here.
If your Ghost is a Ghost-CLI install see our documentation on updating it to the latest version here.
References
Ghost thanks Miguel Segovia Gil of KPMG and Nguyễn Quốc Đồng for disclosing this vulnerability responsibly.
For more information
If you have any questions or comments about this advisory, email us at security@ghost.org.
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "ghost"
},
"ranges": [
{
"events": [
{
"introduced": "1.20.0"
},
{
"fixed": "6.64.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-105676"
],
"database_specific": {
"cwe_ids": [
"CWE-22",
"CWE-73"
],
"github_reviewed": true,
"github_reviewed_at": "2026-10-07T20:26:14Z",
"nvd_published_at": "2026-10-05T20:17:14Z",
"severity": "MODERATE"
},
"details": "### Impact\n\nA vulnerability in how Ghost loads theme translation files allowed an authenticated Administrator to read JSON files outside of the active theme\u0027s directory, potentially exposing server configuration secrets.\n\n### Vulnerable versions\n\nThis vulnerability is present in Ghost from v1.20.0 up to v6.64.0.\n\n### Patches\n\nv6.64.0 contains a fix for this issue.\n\n### How to update\n\nFor self-hosters using Docker, find [Docker\u0027s official Ghost image here](https://hub.docker.com/_/ghost). Updating a Docker-based Ghost instance [is documented here](https://docs.ghost.org/install/docker#updating-ghost).\n\nIf your Ghost is a Ghost-CLI install see our documentation on [updating it to the latest version here](https://docs.ghost.org/update).\n\n### References\n\nGhost thanks Miguel Segovia Gil of KPMG and [Nguy\u1ec5n Qu\u1ed1c \u0110\u1ed3ng](https://github.com/DONG2209) for disclosing this vulnerability responsibly.\n\n### For more information\n\nIf you have any questions or comments about this advisory, email us at [security@ghost.org](mailto:security@ghost.org).",
"id": "GHSA-m382-6jw4-fmp6",
"modified": "2026-10-07T20:26:14Z",
"published": "2026-10-07T20:26:14Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/TryGhost/Ghost/security/advisories/GHSA-m382-6jw4-fmp6"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-105676"
},
{
"type": "WEB",
"url": "https://github.com/TryGhost/Ghost/issues/30635"
},
{
"type": "WEB",
"url": "https://github.com/TryGhost/Ghost/pull/30635"
},
{
"type": "WEB",
"url": "https://github.com/TryGhost/Ghost/commit/d2f498694be549074dd5817fd0e8a1371b65df02"
},
{
"type": "PACKAGE",
"url": "https://github.com/TryGhost/Ghost"
},
{
"type": "WEB",
"url": "https://github.com/TryGhost/Ghost/releases/tag/v6.64.0"
}
],
"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"
}
],
"summary": "Ghost: Path Traversal via Locale Setting"
}
GHSA-M3X4-5JFW-2MQC
Vulnerability from github – Published: 2026-08-13 12:31 – Updated: 2026-08-13 12:31GitPython before 3.1.57 contains an incomplete denylist in the unsafe_git_archive_options guard that omits --add-file and --add-virtual-file options. Attackers can supply these options to Repo.archive() to read arbitrary files from the filesystem and include them in the returned archive.
{
"affected": [],
"aliases": [
"CVE-2026-73619"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-13T12:17:26Z",
"severity": "HIGH"
},
"details": "GitPython before 3.1.57 contains an incomplete denylist in the unsafe_git_archive_options guard that omits --add-file and --add-virtual-file options. Attackers can supply these options to Repo.archive() to read arbitrary files from the filesystem and include them in the returned archive.",
"id": "GHSA-m3x4-5jfw-2mqc",
"modified": "2026-08-13T12:31:11Z",
"published": "2026-08-13T12:31:11Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/gitpython-developers/GitPython/security/advisories/GHSA-539m-9xh6-q6rr"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-73619"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/gitpython-before-arbitrary-file-read-via-repo-archive"
}
],
"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"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/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"
}
]
}
GHSA-M493-43X7-H3MJ
Vulnerability from github – Published: 2026-05-12 18:30 – Updated: 2026-05-12 18:30External control of file name or path in Microsoft Office Word allows an unauthorized attacker to disclose information over a network.
{
"affected": [],
"aliases": [
"CVE-2026-40421"
],
"database_specific": {
"cwe_ids": [
"CWE-73"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-05-12T18:17:20Z",
"severity": "MODERATE"
},
"details": "External control of file name or path in Microsoft Office Word allows an unauthorized attacker to disclose information over a network.",
"id": "GHSA-m493-43x7-h3mj",
"modified": "2026-05-12T18:30:46Z",
"published": "2026-05-12T18:30:45Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-40421"
},
{
"type": "WEB",
"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40421"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-M54H-VHF9-3W3M
Vulnerability from github – Published: 2026-06-18 15:03 – Updated: 2026-06-18 15:03The postman_download module uses the workspace name field from the Postman API to construct the local directory path without sanitization. If a malicious workspace has a name containing path traversal characters, pathlib resolves the path outside the intended output directory, allowing an attacker to write arbitrary files to the user's system.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 2.8.5"
},
"package": {
"ecosystem": "PyPI",
"name": "bbot"
},
"ranges": [
{
"events": [
{
"introduced": "2.1.0"
},
{
"fixed": "2.8.6"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-12568"
],
"database_specific": {
"cwe_ids": [
"CWE-125",
"CWE-22",
"CWE-73"
],
"github_reviewed": true,
"github_reviewed_at": "2026-06-18T15:03:38Z",
"nvd_published_at": "2026-06-17T23:17:03Z",
"severity": "MODERATE"
},
"details": "The `postman_download` module uses the workspace `name` field from the Postman API to construct the local directory path without sanitization. If a malicious workspace has a name containing path traversal characters, pathlib resolves the path outside the intended output directory, allowing an attacker to write arbitrary files to the user\u0027s system.",
"id": "GHSA-m54h-vhf9-3w3m",
"modified": "2026-06-18T15:03:38Z",
"published": "2026-06-18T15:03:38Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/blacklanternsecurity/bbot/security/advisories/GHSA-m54h-vhf9-3w3m"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-12568"
},
{
"type": "WEB",
"url": "https://github.com/blacklanternsecurity/bbot/commit/36bc20818"
},
{
"type": "PACKAGE",
"url": "https://github.com/blacklanternsecurity/bbot"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N",
"type": "CVSS_V3"
}
],
"summary": "BBOT: Arbitrary File Write in postman_download Module"
}
Mitigation
When the set of filenames is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames, 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 provide this capability.
Mitigation
- Run your code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict all access to files within a particular directory.
- Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection.
- This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise.
- Be careful to avoid CWE-243 and other weaknesses related to jails.
Mitigation
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-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
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).
Mitigation
Use OS-level permissions and run as a low-privileged user to limit the scope of any successful attack.
Mitigation
If you are using PHP, configure your application so that it does not use register_globals. During implementation, develop your 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.
Mitigation
Use tools and techniques that require manual (human) analysis, such as penetration testing, threat modeling, and interactive tools that allow the tester to record and modify an active session. These may be more effective than strictly automated techniques. This is especially the case with weaknesses that are related to design and business rules.
CAPEC-13: Subverting Environment Variable Values
The adversary directly or indirectly modifies environment variables used by or controlling the target software. The adversary's goal is to cause the target software to deviate from its expected operation in a manner that benefits the adversary.
CAPEC-267: Leverage Alternate Encoding
An adversary leverages the possibility to encode potentially harmful input or content used by applications such that the applications are ineffective at validating this encoding standard.
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-72: URL Encoding
This attack targets the encoding of the URL. An adversary can take advantage of the multiple way of encoding an URL and abuse the interpretation of the URL.
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.
CAPEC-80: Using UTF-8 Encoding to Bypass Validation Logic
This attack is a specific variation on leveraging alternate encodings to bypass validation logic. This attack leverages the possibility to encode potentially harmful input in UTF-8 and submit it to applications not expecting or effective at validating this encoding standard making input filtering difficult. UTF-8 (8-bit UCS/Unicode Transformation Format) is a variable-length character encoding for Unicode. Legal UTF-8 characters are one to four bytes long. However, early version of the UTF-8 specification got some entries wrong (in some cases it permitted overlong characters). UTF-8 encoders are supposed to use the "shortest possible" encoding, but naive decoders may accept encodings that are longer than necessary. According to the RFC 3629, a particularly subtle form of this attack can be carried out against a parser which performs security-critical validity checks against the UTF-8 encoded form of its input, but interprets certain illegal octet sequences as characters.