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.
13030 vulnerabilities reference this CWE, most recent first.
GHSA-WQJG-QMP7-8Q8X
Vulnerability from github – Published: 2022-05-17 04:00 – Updated: 2022-05-17 04:00Directory traversal vulnerability in IBM Security QRadar SIEM 7.2.x before 7.2.5 Patch 6 allows remote authenticated users to read arbitrary files via a crafted URL.
{
"affected": [],
"aliases": [
"CVE-2015-2007"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2016-01-03T00:59:00Z",
"severity": "MODERATE"
},
"details": "Directory traversal vulnerability in IBM Security QRadar SIEM 7.2.x before 7.2.5 Patch 6 allows remote authenticated users to read arbitrary files via a crafted URL.",
"id": "GHSA-wqjg-qmp7-8q8x",
"modified": "2022-05-17T04:00:02Z",
"published": "2022-05-17T04:00:02Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2015-2007"
},
{
"type": "WEB",
"url": "http://www-01.ibm.com/support/docview.wss?uid=swg21967647"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-WQMJ-6G5M-VV5W
Vulnerability from github – Published: 2021-12-23 00:01 – Updated: 2022-04-20 00:01A directory traversal vulnerability exists in the Web Manager FsBrowseClean functionality of Lantronix PremierWave 2050 8.9.0.0R4 (in QEMU). A specially crafted HTTP request can lead to arbitrary file deletion. An attacker can make an authenticated HTTP request to trigger this vulnerability.
{
"affected": [],
"aliases": [
"CVE-2021-21896"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-12-22T19:15:00Z",
"severity": "MODERATE"
},
"details": "A directory traversal vulnerability exists in the Web Manager FsBrowseClean functionality of Lantronix PremierWave 2050 8.9.0.0R4 (in QEMU). A specially crafted HTTP request can lead to arbitrary file deletion. An attacker can make an authenticated HTTP request to trigger this vulnerability.",
"id": "GHSA-wqmj-6g5m-vv5w",
"modified": "2022-04-20T00:01:59Z",
"published": "2021-12-23T00:01:11Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-21896"
},
{
"type": "WEB",
"url": "https://talosintelligence.com/vulnerability_reports/TALOS-2021-1338"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-WQP9-HQGQ-37F9
Vulnerability from github – Published: 2022-05-01 23:41 – Updated: 2022-05-01 23:41Directory traversal vulnerability in the embedded web server in Image Capture in Apple Mac OS X before 10.5 allows remote attackers to read arbitrary files via directory traversal sequences in the URI.
{
"affected": [],
"aliases": [
"CVE-2008-1571"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2008-06-02T21:30:00Z",
"severity": "MODERATE"
},
"details": "Directory traversal vulnerability in the embedded web server in Image Capture in Apple Mac OS X before 10.5 allows remote attackers to read arbitrary files via directory traversal sequences in the URI.",
"id": "GHSA-wqp9-hqgq-37f9",
"modified": "2022-05-01T23:41:24Z",
"published": "2022-05-01T23:41:24Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2008-1571"
},
{
"type": "WEB",
"url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/42718"
},
{
"type": "WEB",
"url": "http://lists.apple.com/archives/security-announce/2008//May/msg00001.html"
},
{
"type": "WEB",
"url": "http://secunia.com/advisories/30430"
},
{
"type": "WEB",
"url": "http://securitytracker.com/id?1020141"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/29412"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/29501"
},
{
"type": "WEB",
"url": "http://www.us-cert.gov/cas/techalerts/TA08-150A.html"
},
{
"type": "WEB",
"url": "http://www.vupen.com/english/advisories/2008/1697"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-WQPR-5JGG-VF8Q
Vulnerability from github – Published: 2022-05-13 01:28 – Updated: 2022-05-13 01:28Directory traversal vulnerability in opt/arkeia/wui/htdocs/index.php in the WD Arkeia virtual appliance (AVA) with firmware before 10.2.9 allows remote attackers to read arbitrary files and execute arbitrary PHP code via a ..././ (dot dot dot slash dot slash) in the lang Cookie parameter, as demonstrated by a request to login/doLogin.
{
"affected": [],
"aliases": [
"CVE-2014-2846"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2014-04-28T14:09:00Z",
"severity": "HIGH"
},
"details": "Directory traversal vulnerability in opt/arkeia/wui/htdocs/index.php in the WD Arkeia virtual appliance (AVA) with firmware before 10.2.9 allows remote attackers to read arbitrary files and execute arbitrary PHP code via a ..././ (dot dot dot slash dot slash) in the lang Cookie parameter, as demonstrated by a request to login/doLogin.",
"id": "GHSA-wqpr-5jgg-vf8q",
"modified": "2022-05-13T01:28:15Z",
"published": "2022-05-13T01:28:15Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2014-2846"
},
{
"type": "WEB",
"url": "http://seclists.org/fulldisclosure/2014/Apr/257"
},
{
"type": "WEB",
"url": "http://wiki.arkeia.com/index.php/Path_Traversal_Remote_Code_Execution"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/archive/1/531910/100/0/threaded"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-WQR3-24XM-FXHQ
Vulnerability from github – Published: 2020-09-01 17:31 – Updated: 2023-09-11 16:37Affected versions of wffserve resolve relative file paths, resulting in a directory traversal vulnerability. A malicious actor can use this vulnerability to access files outside of the intended directory root, which may result in the disclosure of private files on the vulnerable system.
Example request:
GET /../../../../../../../../../../etc/passwd HTTP/1.1
host:foo
Recommendation
No patch is available for this vulnerability.
It is recommended that the package is only used for local development, and if the functionality is needed for production, a different package is used instead.
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "wffserve"
},
"ranges": [
{
"events": [
{
"introduced": "0.0.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2017-16168"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": true,
"github_reviewed_at": "2020-08-31T18:21:55Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"details": "Affected versions of `wffserve` resolve relative file paths, resulting in a directory traversal vulnerability. A malicious actor can use this vulnerability to access files outside of the intended directory root, which may result in the disclosure of private files on the vulnerable system.\n\n**Example request:**\n```http\nGET /../../../../../../../../../../etc/passwd HTTP/1.1\nhost:foo\n```\n\n\n## Recommendation\n\nNo patch is available for this vulnerability.\n\nIt is recommended that the package is only used for local development, and if the functionality is needed for production, a different package is used instead.",
"id": "GHSA-wqr3-24xm-fxhq",
"modified": "2023-09-11T16:37:49Z",
"published": "2020-09-01T17:31:22Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2017-16168"
},
{
"type": "WEB",
"url": "https://github.com/JacksonGL/NPM-Vuln-PoC/blob/master/directory-traversal/city-weather-abe"
},
{
"type": "WEB",
"url": "https://github.com/JacksonGL/NPM-Vuln-PoC/blob/master/directory-traversal/wffserve"
},
{
"type": "WEB",
"url": "https://www.npmjs.com/advisories/407"
}
],
"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": "Directory Traversal in wffserve"
}
GHSA-WQRX-PVQC-VP73
Vulnerability from github – Published: 2022-07-26 00:00 – Updated: 2022-08-03 00:00A vulnerability in the component process.php of QR Code Generator v5.2.7 allows attackers to perform directory traversal.
{
"affected": [],
"aliases": [
"CVE-2022-24992"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2022-07-25T18:22:00Z",
"severity": "HIGH"
},
"details": "A vulnerability in the component process.php of QR Code Generator v5.2.7 allows attackers to perform directory traversal.",
"id": "GHSA-wqrx-pvqc-vp73",
"modified": "2022-08-03T00:00:55Z",
"published": "2022-07-26T00:00:29Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-24992"
},
{
"type": "WEB",
"url": "https://codecanyon.net/item/qrcdr-responsive-qr-code-generator/9226839"
},
{
"type": "WEB",
"url": "https://n0lsec.medium.com/qrcdr-path-traversal-vulnerability-bb89acc0c100"
},
{
"type": "WEB",
"url": "http://qrcdr.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"
}
]
}
GHSA-WQW6-P8W6-3G29
Vulnerability from github – Published: 2022-05-14 03:51 – Updated: 2022-05-14 03:51Absolute path traversal vulnerability in logShow.htm on the Quantum Scalar i500 tape library with firmware before i7.0.3 (604G.GS00100), also distributed as the Dell ML6000 tape library with firmware before A20-00 (590G.GS00100), allows remote attackers to read arbitrary files via a full pathname in the file parameter.
{
"affected": [],
"aliases": [
"CVE-2012-1841"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2012-03-22T10:17:00Z",
"severity": "MODERATE"
},
"details": "Absolute path traversal vulnerability in logShow.htm on the Quantum Scalar i500 tape library with firmware before i7.0.3 (604G.GS00100), also distributed as the Dell ML6000 tape library with firmware before A20-00 (590G.GS00100), allows remote attackers to read arbitrary files via a full pathname in the file parameter.",
"id": "GHSA-wqw6-p8w6-3g29",
"modified": "2022-05-14T03:51:32Z",
"published": "2022-05-14T03:51:32Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2012-1841"
},
{
"type": "WEB",
"url": "http://osvdb.org/80226"
},
{
"type": "WEB",
"url": "http://secunia.com/advisories/48403"
},
{
"type": "WEB",
"url": "http://secunia.com/advisories/48453"
},
{
"type": "WEB",
"url": "http://www.kb.cert.org/vuls/id/913483"
},
{
"type": "WEB",
"url": "http://www.kb.cert.org/vuls/id/MAPG-8NNKN8"
},
{
"type": "WEB",
"url": "http://www.kb.cert.org/vuls/id/MAPG-8NVRPY"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-WR24-C5P3-2HMR
Vulnerability from github – Published: 2022-05-13 01:34 – Updated: 2022-05-13 01:34The Quick Setup component of RSA Authentication Manager versions prior to 8.4 is vulnerable to a relative path traversal vulnerability. A local attacker could potentially provide an administrator with a crafted license that if used during the quick setup deployment of the initial RSA Authentication Manager system, could allow the attacker unauthorized access to that system.
{
"affected": [],
"aliases": [
"CVE-2018-15782"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2019-01-16T20:29:00Z",
"severity": "HIGH"
},
"details": "The Quick Setup component of RSA Authentication Manager versions prior to 8.4 is vulnerable to a relative path traversal vulnerability. A local attacker could potentially provide an administrator with a crafted license that if used during the quick setup deployment of the initial RSA Authentication Manager system, could allow the attacker unauthorized access to that system.",
"id": "GHSA-wr24-c5p3-2hmr",
"modified": "2022-05-13T01:34:06Z",
"published": "2022-05-13T01:34:06Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2018-15782"
},
{
"type": "WEB",
"url": "https://seclists.org/fulldisclosure/2019/Jan/18"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-WR27-CJ9H-MV7Q
Vulnerability from github – Published: 2022-05-24 19:18 – Updated: 2022-05-24 19:18Sky File v2.1.0 contains a directory traversal vulnerability in the FTP server which allows attackers to access sensitive data and files via 'null' path commands.
{
"affected": [],
"aliases": [
"CVE-2020-23040"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-10-22T20:15:00Z",
"severity": "HIGH"
},
"details": "Sky File v2.1.0 contains a directory traversal vulnerability in the FTP server which allows attackers to access sensitive data and files via \u0027null\u0027 path commands.",
"id": "GHSA-wr27-cj9h-mv7q",
"modified": "2022-05-24T19:18:36Z",
"published": "2022-05-24T19:18:36Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2020-23040"
},
{
"type": "WEB",
"url": "https://www.vulnerability-lab.com/get_content.php?id=2207"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-WR3J-PWJ9-HQQ6
Vulnerability from github – Published: 2024-03-21 18:59 – Updated: 2024-03-21 18:59Summary
The webpack-dev-middleware middleware does not validate the supplied URL address sufficiently before returning the local file. It is possible to access any file on the developer's machine.
Details
The middleware can either work with the physical filesystem when reading the files or it can use a virtualized in-memory memfs filesystem. If writeToDisk configuration option is set to true, the physical filesystem is used: https://github.com/webpack/webpack-dev-middleware/blob/7ed24e0b9f53ad1562343f9f517f0f0ad2a70377/src/utils/setupOutputFileSystem.js#L21
The getFilenameFromUrl method is used to parse URL and build the local file path. The public path prefix is stripped from the URL, and the unsecaped path suffix is appended to the outputPath: https://github.com/webpack/webpack-dev-middleware/blob/7ed24e0b9f53ad1562343f9f517f0f0ad2a70377/src/utils/getFilenameFromUrl.js#L82 As the URL is not unescaped and normalized automatically before calling the midlleware, it is possible to use %2e and %2f sequences to perform path traversal attack.
PoC
A blank project can be created containing the following configuration file webpack.config.js:
module.exports = {
devServer: {
devMiddleware: {
writeToDisk: true
}
}
};
When started, it is possible to access any local file, e.g. /etc/passwd:
$ curl localhost:8080/public/..%2f..%2f..%2f..%2f../etc/passwd
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin
bin:x:2:2:bin:/bin:/usr/sbin/nologin
sys:x:3:3:sys:/dev:/usr/sbin/nologin
sync:x:4:65534:sync:/bin:/bin/sync
games:x:5:60:games:/usr/games:/usr/sbin/nologin
Impact
The developers using webpack-dev-server or webpack-dev-middleware are affected by the issue. When the project is started, an attacker might access any file on the developer's machine and exfiltrate the content (e.g. password, configuration files, private source code, ...).
If the development server is listening on a public IP address (or 0.0.0.0), an attacker on the local network can access the local files without any interaction from the victim (direct connection to the port).
If the server allows access from third-party domains (CORS, Allow-Access-Origin: * ), an attacker can send a malicious link to the victim. When visited, the client side script can connect to the local server and exfiltrate the local files.
Recommendation
The URL should be unescaped and normalized before any further processing.
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "webpack-dev-middleware"
},
"ranges": [
{
"events": [
{
"introduced": "7.0.0"
},
{
"fixed": "7.1.0"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"package": {
"ecosystem": "npm",
"name": "webpack-dev-middleware"
},
"ranges": [
{
"events": [
{
"introduced": "6.0.0"
},
{
"fixed": "6.1.2"
}
],
"type": "ECOSYSTEM"
}
]
},
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 5.3.3"
},
"package": {
"ecosystem": "npm",
"name": "webpack-dev-middleware"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "5.3.4"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2024-29180"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": true,
"github_reviewed_at": "2024-03-21T18:59:28Z",
"nvd_published_at": "2024-03-21T17:15:09Z",
"severity": "HIGH"
},
"details": "### Summary\n_The **webpack-dev-middleware** middleware does not validate the supplied URL address sufficiently before returning the local file. It is possible to access any file on the developer\u0027s machine._\n\n### Details\nThe middleware can either work with the physical filesystem when reading the files or it can use a virtualized in-memory _memfs_ filesystem.\nIf _writeToDisk_ configuration option is set to **true**, the physical filesystem is used:\n[https://github.com/webpack/webpack-dev-middleware/blob/7ed24e0b9f53ad1562343f9f517f0f0ad2a70377/src/utils/setupOutputFileSystem.js#L21](https://github.com/webpack/webpack-dev-middleware/blob/7ed24e0b9f53ad1562343f9f517f0f0ad2a70377/src/utils/setupOutputFileSystem.js#L21)\n\nThe _**getFilenameFromUrl**_ method is used to parse URL and build the local file path.\nThe public path prefix is stripped from the URL, and the **unsecaped** path suffix is appended to the _outputPath_:\n[https://github.com/webpack/webpack-dev-middleware/blob/7ed24e0b9f53ad1562343f9f517f0f0ad2a70377/src/utils/getFilenameFromUrl.js#L82](https://github.com/webpack/webpack-dev-middleware/blob/7ed24e0b9f53ad1562343f9f517f0f0ad2a70377/src/utils/getFilenameFromUrl.js#L82)\nAs the URL is not unescaped and normalized automatically before calling the midlleware, it is possible to use _%2e_ and _%2f_ sequences to perform path traversal attack.\n\n### PoC\n_A blank project can be created containing the following configuration file **webpack.config.js**:_\n`module.exports = {\n devServer: {\n devMiddleware: {\n writeToDisk: true\n }\n }\n};\n`\n\nWhen started, it is possible to access any local file, e.g. _/etc/passwd_:\n`$ curl localhost:8080/public/..%2f..%2f..%2f..%2f../etc/passwd`\n```\nroot:x:0:0:root:/root:/bin/bash\ndaemon:x:1:1:daemon:/usr/sbin:/usr/sbin/nologin\nbin:x:2:2:bin:/bin:/usr/sbin/nologin\nsys:x:3:3:sys:/dev:/usr/sbin/nologin\nsync:x:4:65534:sync:/bin:/bin/sync\ngames:x:5:60:games:/usr/games:/usr/sbin/nologin\n```\n\n### Impact\nThe developers using _webpack-dev-server_ or _webpack-dev-middleware_ are affected by the issue. When the project is started, an attacker might access any file on the developer\u0027s machine and exfiltrate the content (e.g. password, configuration files, private source code, ...).\n\nIf the development server is listening on a public IP address (or **0.0.0.0**), an attacker on the local network can access the local files without any interaction from the victim (direct connection to the port).\n\nIf the server allows access from third-party domains (CORS, **_Allow-Access-Origin: *_** ), an attacker can send a malicious link to the victim. When visited, the client side script can connect to the local server and exfiltrate the local files.\n\n### Recommendation\nThe URL should be unescaped and normalized before any further processing.",
"id": "GHSA-wr3j-pwj9-hqq6",
"modified": "2024-03-21T18:59:28Z",
"published": "2024-03-21T18:59:28Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/webpack/webpack-dev-middleware/security/advisories/GHSA-wr3j-pwj9-hqq6"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-29180"
},
{
"type": "WEB",
"url": "https://github.com/webpack/webpack-dev-middleware/commit/189c4ac7d2344ec132a4689e74dc837ec5be0132"
},
{
"type": "WEB",
"url": "https://github.com/webpack/webpack-dev-middleware/commit/9670b3495da518fe667ff3428c5e4cb9f2f3d353"
},
{
"type": "WEB",
"url": "https://github.com/webpack/webpack-dev-middleware/commit/e10008c762e4d5821ed6990348dabf0d4d93a10e"
},
{
"type": "PACKAGE",
"url": "https://github.com/webpack/webpack-dev-middleware"
},
{
"type": "WEB",
"url": "https://github.com/webpack/webpack-dev-middleware/blob/7ed24e0b9f53ad1562343f9f517f0f0ad2a70377/src/utils/getFilenameFromUrl.js#L82"
},
{
"type": "WEB",
"url": "https://github.com/webpack/webpack-dev-middleware/blob/7ed24e0b9f53ad1562343f9f517f0f0ad2a70377/src/utils/setupOutputFileSystem.js#L21"
},
{
"type": "WEB",
"url": "https://github.com/webpack/webpack-dev-middleware/releases/tag/v5.3.4"
},
{
"type": "WEB",
"url": "https://github.com/webpack/webpack-dev-middleware/releases/tag/v6.1.2"
},
{
"type": "WEB",
"url": "https://github.com/webpack/webpack-dev-middleware/releases/tag/v7.1.0"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N",
"type": "CVSS_V3"
}
],
"summary": "Path traversal in webpack-dev-middleware"
}
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.