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.
13328 vulnerabilities reference this CWE, most recent first.
GHSA-JP6X-8XRV-WW5P
Vulnerability from github – Published: 2022-05-17 05:51 – Updated: 2022-05-17 05:51Directory traversal vulnerability in scr/soustab.php in openMairie Openregistrecil 1.02, when register_globals is enabled, allows remote attackers to include and execute arbitrary local files via directory traversal sequences in the dsn[phptype] parameter. NOTE: this may be related to CVE-2007-2069.
{
"affected": [],
"aliases": [
"CVE-2010-1947"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2010-05-19T12:07:00Z",
"severity": "MODERATE"
},
"details": "Directory traversal vulnerability in scr/soustab.php in openMairie Openregistrecil 1.02, when register_globals is enabled, allows remote attackers to include and execute arbitrary local files via directory traversal sequences in the dsn[phptype] parameter. NOTE: this may be related to CVE-2007-2069.",
"id": "GHSA-jp6x-8xrv-ww5p",
"modified": "2022-05-17T05:51:07Z",
"published": "2022-05-17T05:51:07Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2010-1947"
},
{
"type": "WEB",
"url": "http://packetstormsecurity.org/1004-exploits/openregistrecil-rfilfi.txt"
},
{
"type": "WEB",
"url": "http://secunia.com/advisories/39534"
},
{
"type": "WEB",
"url": "http://www.exploit-db.com/exploits/12313"
},
{
"type": "WEB",
"url": "http://www.osvdb.org/63964"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/39611"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-JP75-4XF8-W783
Vulnerability from github – Published: 2022-05-17 02:11 – Updated: 2022-05-17 02:11Multiple directory traversal vulnerabilities in phpKF-Portal 1.10 allow remote attackers to include arbitrary files via a .. (dot dot) in the (1) tema_dizin parameter to baslik.php and (2) portal_ayarlarportal_dili parameter to anket_yonetim.php. NOTE: the provenance of this information is unknown; the details are obtained solely from third party information.
{
"affected": [],
"aliases": [
"CVE-2008-6516"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2009-03-25T18:30:00Z",
"severity": "HIGH"
},
"details": "Multiple directory traversal vulnerabilities in phpKF-Portal 1.10 allow remote attackers to include arbitrary files via a .. (dot dot) in the (1) tema_dizin parameter to baslik.php and (2) portal_ayarlarportal_dili parameter to anket_yonetim.php. NOTE: the provenance of this information is unknown; the details are obtained solely from third party information.",
"id": "GHSA-jp75-4xf8-w783",
"modified": "2022-05-17T02:11:14Z",
"published": "2022-05-17T02:11:14Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2008-6516"
},
{
"type": "WEB",
"url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/44263"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/30566"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-JP7C-WJ6Q-3QF2
Vulnerability from github – Published: 2026-02-06 18:16 – Updated: 2026-02-06 19:07Summary
A Path Traversal vulnerability exists in the updateWikiPage function of Gogs. The vulnerability allows an authenticated user with write access to a repository's wiki to delete arbitrary files on the server by manipulating the old_title parameter in the wiki editing form.
Vulnerability Deatils
The vulnerability is located in internal/database/wiki.go. When updating a wiki page, the application accepts an old_title parameter to identify the potential rename operation. This parameter is used directly in path.Join and os.Remove without proper sanitization.
Code snippet from internal/database/wiki.go:
// Line 114
os.Remove(path.Join(localPath, oldTitle+".md"))
If an attacker provides a path traversal sequence (e.g., ../../../../target) as old_title, the os.Remove function will resolve the path relative to the wiki's local directory and delete the target file. The vulnerability is limited to deleting files that end with .md (due to the appended extension), but depending on the filesystem and specific path.Join behavior, or if critical .md files exist (e.g. documentation, other wikis), the impact is significant. Additionally, in some contexts, the extension might be bypassed or ignored.
Impact
- Denial of Service: Deletion of critical configuration files or data (if they match the extension or via other tricks).
- Data Loss: Deletion of other users' wiki pages or documentation.
Remediation
Sanitize the oldTitle parameter using ToWikiPageName (or path.Clean and basename validation) before using it in file operations, similar to how the new title is currently handled.
// Recommended Fix
if oldTitle != "" {
oldTitle = ToWikiPageName(oldTitle)
}
Reproduction Steps
- Log in to Gogs as a user with write access to a repository wiki.
- Intercept the
POSTrequest to/repo/wiki/edit. - Modify the
old_titleparameter to../../../../tmp/target_file. - Submit the request.
- Observe that
/tmp/target_file.mdis deleted from the server.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 0.13.3"
},
"package": {
"ecosystem": "Go",
"name": "gogs.io/gogs"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.13.4"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-24135"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": true,
"github_reviewed_at": "2026-02-06T18:16:25Z",
"nvd_published_at": "2026-02-06T18:15:57Z",
"severity": "HIGH"
},
"details": "### Summary\nA Path Traversal vulnerability exists in the `updateWikiPage` function of Gogs. The vulnerability allows an authenticated user with write access to a repository\u0027s wiki to delete arbitrary files on the server by manipulating the `old_title` parameter in the wiki editing form.\n\n### Vulnerability Deatils\nThe vulnerability is located in `internal/database/wiki.go`. When updating a wiki page, the application accepts an `old_title` parameter to identify the potential rename operation. This parameter is used directly in `path.Join` and `os.Remove` without proper sanitization.\n\nCode snippet from `internal/database/wiki.go`:\n```go\n// Line 114\nos.Remove(path.Join(localPath, oldTitle+\".md\"))\n```\n\nIf an attacker provides a path traversal sequence (e.g., `../../../../target`) as `old_title`, the `os.Remove` function will resolve the path relative to the wiki\u0027s local directory and delete the target file. The vulnerability is limited to deleting files that end with `.md` (due to the appended extension), but depending on the filesystem and specific `path.Join` behavior, or if critical `.md` files exist (e.g. documentation, other wikis), the impact is significant. Additionally, in some contexts, the extension might be bypassed or ignored.\n\n### Impact\n- **Denial of Service**: Deletion of critical configuration files or data (if they match the extension or via other tricks).\n- **Data Loss**: Deletion of other users\u0027 wiki pages or documentation.\n\n### Remediation\nSanitize the `oldTitle` parameter using `ToWikiPageName` (or `path.Clean` and basename validation) before using it in file operations, similar to how the new `title` is currently handled.\n\n```go\n// Recommended Fix\nif oldTitle != \"\" {\n oldTitle = ToWikiPageName(oldTitle)\n}\n```\n\n### Reproduction Steps\n1. Log in to Gogs as a user with write access to a repository wiki.\n2. Intercept the `POST` request to `/repo/wiki/edit`.\n3. Modify the `old_title` parameter to `../../../../tmp/target_file`.\n4. Submit the request.\n5. Observe that `/tmp/target_file.md` is deleted from the server.",
"id": "GHSA-jp7c-wj6q-3qf2",
"modified": "2026-02-06T19:07:01Z",
"published": "2026-02-06T18:16:25Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/gogs/gogs/security/advisories/GHSA-jp7c-wj6q-3qf2"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-24135"
},
{
"type": "PACKAGE",
"url": "https://github.com/gogs/gogs"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Gogs vulnerable to arbitrary file deletion via Path Traversal in wiki page update"
}
GHSA-JP7F-GRCV-6MJF
Vulnerability from github – Published: 2021-09-20 19:53 – Updated: 2024-07-08 14:33SharpCompress recreates a hierarchy of directories under destinationDirectory if ExtractFullPath is set to true in options. In order to prevent extraction outside the destination directory the destinationFileName path is verified to begin with fullDestinationDirectoryPath. However it is not enforced that fullDestinationDirectoryPath ends with slash:
public static void WriteEntryToDirectory(IEntry entry,
string destinationDirectory,
ExtractionOptions? options,
Action<string, ExtractionOptions?> write)
{
string destinationFileName;
string file = Path.GetFileName(entry.Key);
string fullDestinationDirectoryPath = Path.GetFullPath(destinationDirectory);
...
throw new ExtractionException("Entry is trying to write a file outside of the destination directory.");
}
If the destinationDirectory is not slash terminated like /home/user/dir it is possible to create a file with a name thats begins as the destination directory one level up from the directory, i.e. /home/user/dir.sh.
Impact
Because of the file name and destination directory constraints the arbitrary file creation impact is limited and depends on the use case.
{
"affected": [
{
"package": {
"ecosystem": "NuGet",
"name": "SharpCompress"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.29"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2021-39208"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": true,
"github_reviewed_at": "2021-09-17T18:37:10Z",
"nvd_published_at": "2021-09-16T15:15:00Z",
"severity": "MODERATE"
},
"details": "SharpCompress recreates a hierarchy of directories under destinationDirectory if ExtractFullPath is set to true in options. In order to prevent extraction outside the destination directory the destinationFileName path is verified to begin with fullDestinationDirectoryPath. However it is not enforced that fullDestinationDirectoryPath ends with slash:\n\n```csharp\npublic static void WriteEntryToDirectory(IEntry entry,\n string destinationDirectory,\n ExtractionOptions? options,\n Action\u003cstring, ExtractionOptions?\u003e write)\n{\n string destinationFileName;\n string file = Path.GetFileName(entry.Key);\n string fullDestinationDirectoryPath = Path.GetFullPath(destinationDirectory);\n...\n throw new ExtractionException(\"Entry is trying to write a file outside of the destination directory.\");\n}\n```\n\nIf the destinationDirectory is not slash terminated like /home/user/dir it is possible to create a file with a name thats begins as the destination directory one level up from the directory, i.e. /home/user/dir.sh.\n\n#### Impact\nBecause of the file name and destination directory constraints the arbitrary file creation impact is limited and depends on the use case.",
"id": "GHSA-jp7f-grcv-6mjf",
"modified": "2024-07-08T14:33:23Z",
"published": "2021-09-20T19:53:42Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/adamhathcock/sharpcompress/security/advisories/GHSA-jp7f-grcv-6mjf"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-39208"
},
{
"type": "WEB",
"url": "https://github.com/adamhathcock/sharpcompress/pull/614"
},
{
"type": "WEB",
"url": "https://github.com/adamhathcock/sharpcompress/commit/ea5c8dc06314c7a5068e7901c51a625224d2b288"
},
{
"type": "PACKAGE",
"url": "https://github.com/adamhathcock/sharpcompress"
},
{
"type": "WEB",
"url": "https://github.com/adamhathcock/sharpcompress/releases/tag/0.29.0"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "Partial path traversal in sharpcompress"
}
GHSA-JP85-XGPV-GW56
Vulnerability from github – Published: 2022-05-24 19:15 – Updated: 2022-05-24 19:15e7d Speed Test (aka speedtest) 0.5.3 allows a path-traversal attack that results in information disclosure via the "GET /.." substring.
{
"affected": [],
"aliases": [
"CVE-2021-40349"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-09-27T06:15:00Z",
"severity": "MODERATE"
},
"details": "e7d Speed Test (aka speedtest) 0.5.3 allows a path-traversal attack that results in information disclosure via the \"GET /..\" substring.",
"id": "GHSA-jp85-xgpv-gw56",
"modified": "2022-05-24T19:15:54Z",
"published": "2022-05-24T19:15:54Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-40349"
},
{
"type": "WEB",
"url": "https://github.com/e7d/speedtest/releases"
},
{
"type": "WEB",
"url": "https://old.reddit.com/r/HackingTechniques/comments/poc55t/directory_traversal_bypass_on_e7d_speedtest"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-JP87-2FQ2-66F4
Vulnerability from github – Published: 2026-04-29 00:30 – Updated: 2026-04-29 00:30A vulnerability was detected in eiceblue spire-doc-mcp-server 1.0.0. This affects the function get_doc_path of the file src/spire_doc_mcp/api/base.py. Performing a manipulation of the argument document_name results in path traversal. The attack can be initiated remotely. The exploit is now public and may be used. The project was informed of the problem early through an issue report but has not responded yet.
{
"affected": [],
"aliases": [
"CVE-2026-7314"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-04-28T22:16:51Z",
"severity": "MODERATE"
},
"details": "A vulnerability was detected in eiceblue spire-doc-mcp-server 1.0.0. This affects the function get_doc_path of the file src/spire_doc_mcp/api/base.py. Performing a manipulation of the argument document_name results in path traversal. The attack can be initiated remotely. The exploit is now public and may be used. The project was informed of the problem early through an issue report but has not responded yet.",
"id": "GHSA-jp87-2fq2-66f4",
"modified": "2026-04-29T00:30:23Z",
"published": "2026-04-29T00:30:23Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-7314"
},
{
"type": "WEB",
"url": "https://github.com/eiceblue/spire-doc-mcp-server/issues/1"
},
{
"type": "WEB",
"url": "https://github.com/eiceblue/spire-doc-mcp-server"
},
{
"type": "WEB",
"url": "https://vuldb.com/submit/803080"
},
{
"type": "WEB",
"url": "https://vuldb.com/vuln/359962"
},
{
"type": "WEB",
"url": "https://vuldb.com/vuln/359962/cti"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/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-JP89-XGXV-777W
Vulnerability from github – Published: 2022-02-16 00:01 – Updated: 2022-02-24 00:01kkFileview v4.0.0 has arbitrary file read through a directory traversal vulnerability which may lead to sensitive file leak on related host.
{
"affected": [],
"aliases": [
"CVE-2021-43734"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2022-02-15T14:15:00Z",
"severity": "HIGH"
},
"details": "kkFileview v4.0.0 has arbitrary file read through a directory traversal vulnerability which may lead to sensitive file leak on related host.",
"id": "GHSA-jp89-xgxv-777w",
"modified": "2022-02-24T00:01:09Z",
"published": "2022-02-16T00:01:46Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-43734"
},
{
"type": "WEB",
"url": "https://github.com/kekingcn/kkFileView/issues/304"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-JP8W-XW86-MWCX
Vulnerability from github – Published: 2022-05-17 05:39 – Updated: 2022-05-17 05:39Directory traversal vulnerability in the web server in Cogent DataHub 7.1.1.63 and earlier allows remote attackers to read arbitrary files via a ..\ (dot dot backslash) in an HTTP request.
{
"affected": [],
"aliases": [
"CVE-2011-3500"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2011-09-16T17:26:00Z",
"severity": "MODERATE"
},
"details": "Directory traversal vulnerability in the web server in Cogent DataHub 7.1.1.63 and earlier allows remote attackers to read arbitrary files via a ..\\ (dot dot backslash) in an HTTP request.",
"id": "GHSA-jp8w-xw86-mwcx",
"modified": "2022-05-17T05:39:23Z",
"published": "2022-05-17T05:39:22Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2011-3500"
},
{
"type": "WEB",
"url": "http://aluigi.altervista.org/adv/cogent_2-adv.txt"
},
{
"type": "WEB",
"url": "http://www.us-cert.gov/control_systems/pdf/ICS-ALERT-11-256-03.pdf"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-JP99-GP4P-V5CC
Vulnerability from github – Published: 2026-07-23 18:31 – Updated: 2026-07-23 18:31Office-Word-MCP-Server through 1.1.11 contains a path traversal vulnerability in its document tools that allows attackers who can influence the filename argument to read arbitrary .docx files or create and overwrite .docx files outside the intended working directory. Attackers can supply absolute paths or ../ traversal sequences directly to document open and save operations, bypassing the check_file_writeable and ensure_docx_extension helpers which perform no base-directory confinement or realpath validation.
{
"affected": [],
"aliases": [
"CVE-2026-65695"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-23T17:16:29Z",
"severity": "HIGH"
},
"details": "Office-Word-MCP-Server through 1.1.11 contains a path traversal vulnerability in its document tools that allows attackers who can influence the filename argument to read arbitrary .docx files or create and overwrite .docx files outside the intended working directory. Attackers can supply absolute paths or ../ traversal sequences directly to document open and save operations, bypassing the check_file_writeable and ensure_docx_extension helpers which perform no base-directory confinement or realpath validation.",
"id": "GHSA-jp99-gp4p-v5cc",
"modified": "2026-07-23T18:31:45Z",
"published": "2026-07-23T18:31:45Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-65695"
},
{
"type": "WEB",
"url": "https://github.com/geo-chen/oss/blob/main/Office-Word-MCP-Server.md"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/office-word-mcp-server-path-traversal-via-document-tools"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:H/VI:H/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-JPC4-X6X2-7PM8
Vulnerability from github – Published: 2023-01-10 12:30 – Updated: 2023-01-14 03:30A vulnerability has been identified in SINEC INS (All versions < V1.0 SP2 Update 1). An authenticated remote attacker with access to the Web Based Management (443/tcp) of the affected product, could potentially read and write arbitrary files from and to the device's file system. An attacker might leverage this to trigger remote code execution on the affected component.
{
"affected": [],
"aliases": [
"CVE-2022-45092"
],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-01-10T12:15:00Z",
"severity": "HIGH"
},
"details": "A vulnerability has been identified in SINEC INS (All versions \u003c V1.0 SP2 Update 1). An authenticated remote attacker with access to the Web Based Management (443/tcp) of the affected product, could potentially read and write arbitrary files from and to the device\u0027s file system. An attacker might leverage this to trigger remote code execution on the affected component.",
"id": "GHSA-jpc4-x6x2-7pm8",
"modified": "2023-01-14T03:30:22Z",
"published": "2023-01-10T12:30:23Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-45092"
},
{
"type": "WEB",
"url": "https://cert-portal.siemens.com/productcert/pdf/ssa-332410.pdf"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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.