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.
13242 vulnerabilities reference this CWE, most recent first.
GHSA-6V3V-C95X-RPQ9
Vulnerability from github – Published: 2022-05-13 01:31 – Updated: 2022-05-13 01:31A vulnerability in the TFTP service of Cisco Network Convergence System 1000 Series software could allow an unauthenticated, remote attacker to retrieve arbitrary files from the targeted device, possibly resulting in information disclosure. The vulnerability is due to improper validation of user-supplied input within TFTP requests processed by the affected software. An attacker could exploit this vulnerability by using directory traversal techniques in malicious requests sent to the TFTP service on a targeted device. An exploit could allow the attacker to retrieve arbitrary files from the targeted device, resulting in the disclosure of sensitive information. This vulnerability affects Cisco IOS XR Software releases prior to Release 6.5.2 for Cisco Network Convergence System 1000 Series devices when the TFTP service is enabled.
{
"affected": [],
"aliases": [
"CVE-2019-1681"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2019-02-21T20:29:00Z",
"severity": "HIGH"
},
"details": "A vulnerability in the TFTP service of Cisco Network Convergence System 1000 Series software could allow an unauthenticated, remote attacker to retrieve arbitrary files from the targeted device, possibly resulting in information disclosure. The vulnerability is due to improper validation of user-supplied input within TFTP requests processed by the affected software. An attacker could exploit this vulnerability by using directory traversal techniques in malicious requests sent to the TFTP service on a targeted device. An exploit could allow the attacker to retrieve arbitrary files from the targeted device, resulting in the disclosure of sensitive information. This vulnerability affects Cisco IOS XR Software releases prior to Release 6.5.2 for Cisco Network Convergence System 1000 Series devices when the TFTP service is enabled.",
"id": "GHSA-6v3v-c95x-rpq9",
"modified": "2022-05-13T01:31:25Z",
"published": "2022-05-13T01:31:25Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-1681"
},
{
"type": "WEB",
"url": "https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190220-ncs"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/107107"
}
],
"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-6V48-FCQ6-FF23
Vulnerability from github – Published: 2026-02-24 21:43 – Updated: 2026-02-27 20:40The CreateNewDAG API endpoint (POST /api/v1/dags) does not validate the DAG name before passing it to the file store. While RenameDAG calls core.ValidateDAGName() to reject names containing path separators (line 273 in dags.go), CreateNewDAG skips this validation entirely and passes user input directly to dagStore.Create().
In internal/persis/filedag/store.go, the generateFilePath function (line 493) checks if the name contains a path separator, and if so, resolves it via filepath.Abs(name) — completely ignoring the baseDir. This means a name like ../../tmp/pwned will write a file to /tmp/pwned.yaml instead of the DAGs directory.
Affected code:
internal/service/frontend/api/v1/dags.go line 120-170 — CreateNewDAG handler, no call to ValidateDAGName
internal/persis/filedag/store.go line 493-498 — generateFilePath resolves absolute path when name contains separator
internal/persis/filedag/store.go line 213 — Create calls generateFilePath and writes attacker-controlled YAML content to the resolved path
PoC:
curl -X POST http://localhost:8080/api/v1/dags \
-H "Content-Type: application/json" \
-d '{
"name": "../../tmp/path-traversal-proof",
"spec": "steps:\n - command: id > /tmp/pwned\n"
}'
After this request, a file /tmp/path-traversal-proof.yaml will be created with the attacker-supplied content. The file will be written with the permissions of the dagu process.
An authenticated user with DAG write permissions can write arbitrary YAML files anywhere on the filesystem (limited by the process permissions). Since dagu executes DAG files as shell commands, writing a malicious DAG to the DAGs directory of another instance or overwriting config files can lead to remote code execution.
{
"affected": [
{
"package": {
"ecosystem": "Go",
"name": "github.com/dagu-org/dagu"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"last_affected": "1.16.7"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-27598"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": true,
"github_reviewed_at": "2026-02-24T21:43:15Z",
"nvd_published_at": "2026-02-25T01:16:09Z",
"severity": "HIGH"
},
"details": "The `CreateNewDAG` API endpoint (`POST /api/v1/dags`) does not validate the DAG name before passing it to the file store. While `RenameDAG` calls `core.ValidateDAGName()` to reject names containing path separators (line 273 in `dags.go`), `CreateNewDAG` skips this validation entirely and passes user input directly to `dagStore.Create()`.\n\nIn `internal/persis/filedag/store.go`, the `generateFilePath` function (line 493) checks if the name contains a path separator, and if so, resolves it via `filepath.Abs(name)` \u2014 completely ignoring the `baseDir`. This means a name like `../../tmp/pwned` will write a file to `/tmp/pwned.yaml` instead of the DAGs directory.\n\n**Affected code:**\n\n`internal/service/frontend/api/v1/dags.go` line 120-170 \u2014 `CreateNewDAG` handler, no call to `ValidateDAGName`\n\n`internal/persis/filedag/store.go` line 493-498 \u2014 `generateFilePath` resolves absolute path when name contains separator\n\n`internal/persis/filedag/store.go` line 213 \u2014 `Create` calls `generateFilePath` and writes attacker-controlled YAML content to the resolved path\n\n**PoC:**\n\n```\ncurl -X POST http://localhost:8080/api/v1/dags \\\n -H \"Content-Type: application/json\" \\\n -d \u0027{\n \"name\": \"../../tmp/path-traversal-proof\",\n \"spec\": \"steps:\\n - command: id \u003e /tmp/pwned\\n\"\n }\u0027\n```\n\nAfter this request, a file `/tmp/path-traversal-proof.yaml` will be created with the attacker-supplied content. The file will be written with the permissions of the dagu process.\n\nAn authenticated user with DAG write permissions can write arbitrary YAML files anywhere on the filesystem (limited by the process permissions). Since dagu executes DAG files as shell commands, writing a malicious DAG to the DAGs directory of another instance or overwriting config files can lead to remote code execution.",
"id": "GHSA-6v48-fcq6-ff23",
"modified": "2026-02-27T20:40:23Z",
"published": "2026-02-24T21:43:15Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/dagu-org/dagu/security/advisories/GHSA-6v48-fcq6-ff23"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-27598"
},
{
"type": "WEB",
"url": "https://github.com/dagu-org/dagu/commit/e2ed589105d79273e4e6ac8eb31525f765bb3ce4"
},
{
"type": "PACKAGE",
"url": "https://github.com/dagu-org/dagu"
},
{
"type": "WEB",
"url": "https://pkg.go.dev/vuln/GO-2026-4542"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Dagu: Path traversal in DAG creation allows arbitrary YAML file write outside DAGs directory"
}
GHSA-6V5Q-HW53-JVH9
Vulnerability from github – Published: 2025-05-23 15:31 – Updated: 2026-04-01 18:35Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') vulnerability in wpjobportal WP Job Portal allows Path Traversal. This issue affects WP Job Portal: from n/a through 2.3.2.
{
"affected": [],
"aliases": [
"CVE-2025-48273"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-05-23T13:15:44Z",
"severity": "HIGH"
},
"details": "Improper Limitation of a Pathname to a Restricted Directory (\u0027Path Traversal\u0027) vulnerability in wpjobportal WP Job Portal allows Path Traversal. This issue affects WP Job Portal: from n/a through 2.3.2.",
"id": "GHSA-6v5q-hw53-jvh9",
"modified": "2026-04-01T18:35:16Z",
"published": "2025-05-23T15:31:16Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-48273"
},
{
"type": "WEB",
"url": "https://patchstack.com/database/wordpress/plugin/wp-job-portal/vulnerability/wordpress-wp-job-portal-2-3-2-arbitrary-file-download-vulnerability?_s_id=cve"
}
],
"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-6V6G-J5FQ-HPVW
Vulnerability from github – Published: 2024-06-06 18:30 – Updated: 2025-10-15 15:49A local file inclusion vulnerability exists in the JSON component of gradio-app/gradio and was discovered in version 4.25. The vulnerability arises from improper input validation in the postprocess() function within gradio/components/json_component.py, where a user-controlled string is parsed as JSON. If the parsed JSON object contains a path key, the specified file is moved to a temporary directory, making it possible to retrieve it later via the /file=.. endpoint. This issue is due to the processing_utils.move_files_to_cache() function traversing any object passed to it, looking for a dictionary with a path key, and then copying the specified file to a temporary directory. The vulnerability can be exploited by an attacker to read files on the remote system, posing a significant security risk.
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "gradio"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "4.31.3"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2024-4941"
],
"database_specific": {
"cwe_ids": [
"CWE-20",
"CWE-22"
],
"github_reviewed": true,
"github_reviewed_at": "2024-06-06T22:13:47Z",
"nvd_published_at": "2024-06-06T18:15:18Z",
"severity": "HIGH"
},
"details": "A local file inclusion vulnerability exists in the JSON component of gradio-app/gradio and was discovered in version 4.25. The vulnerability arises from improper input validation in the `postprocess()` function within `gradio/components/json_component.py`, where a user-controlled string is parsed as JSON. If the parsed JSON object contains a `path` key, the specified file is moved to a temporary directory, making it possible to retrieve it later via the `/file=..` endpoint. This issue is due to the `processing_utils.move_files_to_cache()` function traversing any object passed to it, looking for a dictionary with a `path` key, and then copying the specified file to a temporary directory. The vulnerability can be exploited by an attacker to read files on the remote system, posing a significant security risk.",
"id": "GHSA-6v6g-j5fq-hpvw",
"modified": "2025-10-15T15:49:07Z",
"published": "2024-06-06T18:30:58Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-4941"
},
{
"type": "WEB",
"url": "https://github.com/gradio-app/gradio/commit/ee1e2942e0a1ae84a08a05464e41c8108a03fa9c"
},
{
"type": "PACKAGE",
"url": "https://github.com/gradio-app/gradio"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/gradio/PYSEC-2024-184.yaml"
},
{
"type": "WEB",
"url": "https://huntr.com/bounties/39889ce1-298d-4568-aecd-7ae40c2ca58e"
}
],
"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"
}
],
"summary": "Local file inclusion in gradio"
}
GHSA-6V8G-PM53-9XW3
Vulnerability from github – Published: 2023-11-14 21:31 – Updated: 2023-11-14 21:31Path transversal in some Intel(R) NUC P14E Laptop Element Audio Install Package software before version 156 for Windows may allow an authenticated user to potentially enable escalation of privilege via local access.
{
"affected": [],
"aliases": [
"CVE-2023-33878"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-11-14T19:15:27Z",
"severity": "MODERATE"
},
"details": "Path transversal in some Intel(R) NUC P14E Laptop Element Audio Install Package software before version 156 for Windows may allow an authenticated user to potentially enable escalation of privilege via local access.",
"id": "GHSA-6v8g-pm53-9xw3",
"modified": "2023-11-14T21:31:02Z",
"published": "2023-11-14T21:31:02Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-33878"
},
{
"type": "WEB",
"url": "https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00908.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-6VCC-V9VW-G2X5
Vulnerability from github – Published: 2022-06-08 22:34 – Updated: 2022-06-17 19:20Impact
The malicious user is able to craft HTTP requests to access unauthorized Git directories. All installations with are affected.
Patches
Path cleaning has accommodated for Git HTTP endpoints. Users should upgrade to 0.12.9 or the latest 0.13.0+dev.
Workarounds
N/A
References
https://huntr.dev/bounties/22f9c074-cf60-4c67-b5c4-72fdf312609d/
For more information
If you have any questions or comments about this advisory, please post on #7002.
{
"affected": [
{
"package": {
"ecosystem": "Go",
"name": "gogs.io/gogs"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.12.9"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2022-1993"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": true,
"github_reviewed_at": "2022-06-08T22:34:23Z",
"nvd_published_at": "2022-06-09T17:15:00Z",
"severity": "HIGH"
},
"details": "### Impact\n\nThe malicious user is able to craft HTTP requests to access unauthorized Git directories. All installations with are affected.\n\n### Patches\n\nPath cleaning has accommodated for Git HTTP endpoints. Users should upgrade to 0.12.9 or the latest 0.13.0+dev.\n\n### Workarounds\n\nN/A\n\n### References\n\nhttps://huntr.dev/bounties/22f9c074-cf60-4c67-b5c4-72fdf312609d/\n\n### For more information\n\nIf you have any questions or comments about this advisory, please post on #7002.\n",
"id": "GHSA-6vcc-v9vw-g2x5",
"modified": "2022-06-17T19:20:55Z",
"published": "2022-06-08T22:34:23Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/gogs/gogs/security/advisories/GHSA-6vcc-v9vw-g2x5"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-1993"
},
{
"type": "WEB",
"url": "https://github.com/gogs/gogs/issues/7002"
},
{
"type": "WEB",
"url": "https://github.com/gogs/gogs/commit/9bf748b6c4c9a17d3aa77f6b9abcfae65451febf"
},
{
"type": "PACKAGE",
"url": "https://github.com/gogs/gogs"
},
{
"type": "WEB",
"url": "https://huntr.dev/bounties/22f9c074-cf60-4c67-b5c4-72fdf312609d"
}
],
"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:N",
"type": "CVSS_V3"
}
],
"summary": "Path Traversal in Git HTTP endpoints in Gogs"
}
GHSA-6VFP-9JJ7-G4X4
Vulnerability from github – Published: 2022-05-14 02:37 – Updated: 2022-05-14 02:37Absolute path traversal vulnerability in the Disk Usage module (frontend/x/diskusage/index.html) in cPanel 11.18.3 allows remote attackers to list arbitrary directories via the showtree parameter.
{
"affected": [],
"aliases": [
"CVE-2008-7142"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2009-09-01T16:30:00Z",
"severity": "MODERATE"
},
"details": "Absolute path traversal vulnerability in the Disk Usage module (frontend/x/diskusage/index.html) in cPanel 11.18.3 allows remote attackers to list arbitrary directories via the showtree parameter.",
"id": "GHSA-6vfp-9jj7-g4x4",
"modified": "2022-05-14T02:37:40Z",
"published": "2022-05-14T02:37:40Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2008-7142"
},
{
"type": "WEB",
"url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/41266"
},
{
"type": "WEB",
"url": "http://osvdb.org/51582"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/archive/1/489747/100/0/threaded"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/28300"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/28300/exploit"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-6VGW-5PG2-W6JP
Vulnerability from github – Published: 2026-02-02 15:30 – Updated: 2026-02-02 22:08When pip is installing and extracting a maliciously crafted wheel archive, files may be extracted outside the installation directory. The path traversal is limited to prefixes of the installation directory, thus isn't able to inject or overwrite executable files in typical situations.
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "pip"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "26.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-1703"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": true,
"github_reviewed_at": "2026-02-02T22:08:51Z",
"nvd_published_at": "2026-02-02T15:16:30Z",
"severity": "LOW"
},
"details": "When pip is installing and extracting a maliciously crafted wheel archive, files may be extracted outside the installation directory. The path traversal is limited to prefixes of the installation directory, thus isn\u0027t able to inject or overwrite executable files in typical situations.",
"id": "GHSA-6vgw-5pg2-w6jp",
"modified": "2026-02-02T22:08:51Z",
"published": "2026-02-02T15:30:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-1703"
},
{
"type": "WEB",
"url": "https://github.com/pypa/pip/pull/13777"
},
{
"type": "WEB",
"url": "https://github.com/pypa/pip/commit/8e227a9be4faa9594e05d02ca05a413a2a4e7735"
},
{
"type": "PACKAGE",
"url": "https://github.com/pypa/pip"
},
{
"type": "WEB",
"url": "https://mail.python.org/archives/list/security-announce@python.org/thread/WIEA34D4TABF2UNQJAOMXKCICSPBE2DJ"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "pip Path Traversal vulnerability"
}
GHSA-6VHP-2XHP-9H5R
Vulnerability from github – Published: 2025-03-31 18:31 – Updated: 2025-03-31 18:31Xorcom CompletePBX is vulnerable to an authenticated path traversal, allowing for arbitrary file reads via the Backup and Restore functionality.This issue affects CompletePBX: through 5.2.35.
{
"affected": [],
"aliases": [
"CVE-2025-2292"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-03-31T17:15:40Z",
"severity": "MODERATE"
},
"details": "Xorcom CompletePBX is vulnerable to an authenticated path traversal, allowing for arbitrary file reads via the Backup and Restore functionality.This issue affects CompletePBX: through 5.2.35.",
"id": "GHSA-6vhp-2xhp-9h5r",
"modified": "2025-03-31T18:31:08Z",
"published": "2025-03-31T18:31:08Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-2292"
},
{
"type": "WEB",
"url": "https://vulncheck.com/advisories/completepbx-file-disclosure"
},
{
"type": "WEB",
"url": "https://www.xorcom.com/new-completepbx-release-5-2-36-1"
}
],
"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-6VJ6-PQRX-QCX6
Vulnerability from github – Published: 2022-05-17 05:05 – Updated: 2022-05-17 05:05Absolute path traversal vulnerability in the handleStartDataFile function in DigiDocSAXParser.c in libdigidoc 3.6.0.0, as used in ID-software before 3.7.2 and other products, allows remote attackers to overwrite arbitrary files via a filename beginning with / (slash) or \ (backslash) in a DDOC file.
{
"affected": [],
"aliases": [
"CVE-2013-5648"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2013-08-29T12:07:00Z",
"severity": "MODERATE"
},
"details": "Absolute path traversal vulnerability in the handleStartDataFile function in DigiDocSAXParser.c in libdigidoc 3.6.0.0, as used in ID-software before 3.7.2 and other products, allows remote attackers to overwrite arbitrary files via a filename beginning with / (slash) or \\ (backslash) in a DDOC file.",
"id": "GHSA-6vj6-pqrx-qcx6",
"modified": "2022-05-17T05:05:39Z",
"published": "2022-05-17T05:05:39Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2013-5648"
},
{
"type": "WEB",
"url": "https://bugs.mageia.org/show_bug.cgi?id=11100"
},
{
"type": "WEB",
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=1002299"
},
{
"type": "WEB",
"url": "http://svnweb.mageia.org/packages/updates/3/libdigidoc/current/SOURCES/libdigidoc-3.6.0.0-security-fix-DataFile-name-tag.patch?revision=472660\u0026view=markup"
},
{
"type": "WEB",
"url": "http://www.id.ee/?lang=en\u0026id=34283#3_7_2"
}
],
"schema_version": "1.4.0",
"severity": []
}
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.