CWE-88
AllowedImproper Neutralization of Argument Delimiters in a Command ('Argument Injection')
Abstraction: Base · Status: Draft
The product constructs a string for a command to be executed by a separate component in another control sphere, but it does not properly delimit the intended arguments, options, or switches within that command string.
550 vulnerabilities reference this CWE, most recent first.
GHSA-VW27-FWJF-5QXM
Vulnerability from github – Published: 2021-10-22 16:20 – Updated: 2024-10-16 20:48Impact
Starting with qutebrowser v1.7.0, the Windows installer for qutebrowser registers it as a handler for certain URL schemes. With some applications such as Outlook Desktop, opening a specially crafted URL can lead to argument injection, allowing execution of qutebrowser commands, which in turn allows arbitrary code execution via commands such as :spawn or :debug-pyeval.
Only Windows installs where qutebrowser is registered as URL handler are affected. It does not have to be set as default browser for the exploit to work.
Patches
The issue has been fixed in qutebrowser v2.4.0 in commit 8f46ba3f6dc7b18375f7aa63c48a1fe461190430.
The fix also adds additional hardening for potential similar issues on Linux (by adding the new --untrusted-args flag to the .desktop file), though no such vulnerabilities are known.
Backported patches for older versions are available, but no further releases are planned:
- v1.7.x: d1ceaab
- v1.8.x: ca7155d
- v1.9.x: 157d871
- v1.10.x: 94a6125
- v1.11.x: 10acfbb
- v1.12.x: 363a18f
- v1.13.x: 410f262
- v1.14.x: e4f4d93
- v2.0.x: 15a1654
- v2.1.x: 509ddf2
- v2.2.x: 03dcba5
- v2.3.x: 00a694c
(commits are referring to qutebrowser/qutebrowser on GitHub)
Workarounds
Remove qutebrowser from the default browser settings entirely, so that it does not handle any kind of URLs. Make sure to remove all handlers, including an (accidental) qutebrowserURL handler, e.g. using NirSoft URLProtocolView.
Timeline
2021-10-15: Issue reported via security@qutebrowser.org by Ping Fan (Zetta) Ke of Valkyrie-X Security Research Group (VXRL) 2021-10-15: Issue confirmed by @The-Compiler (lead developer), author of installer (@bitraid) contacted for help/review 2021-10-15: CVE assigned by GitHub 2021-10-15 to 2021-10-17: Fix developed 2021-10-17: Additional core developer (@toofar) contacted for help/review 2021-10-21: v2.4.0 released containing the fix 2021-10-21: Advisory and fix published
References
See the commit message for additional information and references to various similar issues in other projects.
Acknowledgements
Thanks to Ping Fan (Zetta) Ke of Valkyrie-X Security Research Group (VXRL/@vxresearch) for finding and responsibly disclosing this issue.
Contact
If you have any questions or comments about this advisory, please email security@qutebrowser.org.
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "qutebrowser"
},
"ranges": [
{
"events": [
{
"introduced": "1.7.0"
},
{
"fixed": "2.4.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2021-41146"
],
"database_specific": {
"cwe_ids": [
"CWE-641",
"CWE-77",
"CWE-88"
],
"github_reviewed": true,
"github_reviewed_at": "2021-10-21T20:46:42Z",
"nvd_published_at": "2021-10-21T18:15:00Z",
"severity": "HIGH"
},
"details": "### Impact\nStarting with qutebrowser v1.7.0, the Windows installer for qutebrowser registers it as a handler for certain URL schemes. With some applications such as Outlook Desktop, opening a specially crafted URL can lead to argument injection, allowing execution of qutebrowser commands, which in turn allows arbitrary code execution via commands such as `:spawn` or `:debug-pyeval`.\n\nOnly Windows installs where qutebrowser is registered as URL handler are affected. It does *not* have to be set as default browser for the exploit to work.\n\n### Patches\nThe issue has been fixed in [qutebrowser v2.4.0](https://github.com/qutebrowser/qutebrowser/releases/tag/v2.4.0) in commit 8f46ba3f6dc7b18375f7aa63c48a1fe461190430.\n\nThe fix also adds additional hardening for potential similar issues on Linux (by adding the new `--untrusted-args` flag to the `.desktop` file), though no such vulnerabilities are known.\n\nBackported patches for older versions are available, but no further releases are planned:\n\n- v1.7.x: d1ceaab\n- v1.8.x: ca7155d\n- v1.9.x: 157d871\n- v1.10.x: 94a6125\n- v1.11.x: 10acfbb\n- v1.12.x: 363a18f\n- v1.13.x: 410f262\n- v1.14.x: e4f4d93\n- v2.0.x: 15a1654\n- v2.1.x: 509ddf2\n- v2.2.x: 03dcba5\n- v2.3.x: 00a694c\n\n(commits are referring to qutebrowser/qutebrowser on GitHub)\n\n### Workarounds\nRemove qutebrowser from the default browser settings entirely, so that it does not handle any kind of URLs. Make sure to remove *all* handlers, including an (accidental) `qutebrowserURL` handler, e.g. using [NirSoft URLProtocolView](https://www.nirsoft.net/utils/url_protocol_view.html).\n\n### Timeline\n2021-10-15: Issue reported via security@qutebrowser.org by Ping Fan (Zetta) Ke of [Valkyrie-X Security Research Group (VXRL)](https://www.vxrl.hk/)\n2021-10-15: Issue confirmed by @The-Compiler (lead developer), author of installer (@bitraid) contacted for help/review\n2021-10-15: CVE assigned by GitHub\n2021-10-15 to 2021-10-17: Fix developed\n2021-10-17: Additional core developer (@toofar) contacted for help/review\n2021-10-21: v2.4.0 released containing the fix\n2021-10-21: Advisory and fix published\n\n### References\nSee the [commit message](https://github.com/qutebrowser/qutebrowser/commit/8f46ba3f6dc7b18375f7aa63c48a1fe461190430) for additional information and references to various similar issues in other projects.\n\n### Acknowledgements\nThanks to Ping Fan (Zetta) Ke of [Valkyrie-X Security Research Group](https://www.vxrl.hk/) (VXRL/@vxresearch) for finding and responsibly disclosing this issue.\n\n### Contact\nIf you have any questions or comments about this advisory, please email [security@qutebrowser.org](mailto:security@qutebrowser.org).",
"id": "GHSA-vw27-fwjf-5qxm",
"modified": "2024-10-16T20:48:13Z",
"published": "2021-10-22T16:20:10Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/qutebrowser/qutebrowser/security/advisories/GHSA-vw27-fwjf-5qxm"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-41146"
},
{
"type": "WEB",
"url": "https://github.com/qutebrowser/qutebrowser/commit/8f46ba3f6dc7b18375f7aa63c48a1fe461190430"
},
{
"type": "WEB",
"url": "https://github.com/pypa/advisory-database/tree/main/vulns/qutebrowser/PYSEC-2021-382.yaml"
},
{
"type": "PACKAGE",
"url": "https://github.com/qutebrowser/qutebrowser"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "Arbitrary command execution on Windows via qutebrowserurl: URL handler"
}
GHSA-VWRX-C7F2-W23M
Vulnerability from github – Published: 2022-05-24 19:04 – Updated: 2022-05-24 19:04KuaiFanCMS V5.x contains an arbitrary file read vulnerability in the html_url parameter of the chakanhtml.module.php file.
{
"affected": [],
"aliases": [
"CVE-2021-3256"
],
"database_specific": {
"cwe_ids": [
"CWE-88"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-06-11T20:15:00Z",
"severity": "MODERATE"
},
"details": "KuaiFanCMS V5.x contains an arbitrary file read vulnerability in the html_url parameter of the chakanhtml.module.php file.",
"id": "GHSA-vwrx-c7f2-w23m",
"modified": "2022-05-24T19:04:57Z",
"published": "2022-05-24T19:04:57Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-3256"
},
{
"type": "WEB",
"url": "https://github.com/poropro/kuaifan/issues/3"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-VX65-QFV7-JCF4
Vulnerability from github – Published: 2022-05-13 01:08 – Updated: 2022-05-13 01:08Insufficient sanitization of arguments passed to rsync can bypass the restrictions imposed by rssh, a restricted shell that should restrict users to perform only rsync operations, resulting in the execution of arbitrary shell commands.
{
"affected": [],
"aliases": [
"CVE-2019-3463"
],
"database_specific": {
"cwe_ids": [
"CWE-88"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2019-02-06T19:29:00Z",
"severity": "CRITICAL"
},
"details": "Insufficient sanitization of arguments passed to rsync can bypass the restrictions imposed by rssh, a restricted shell that should restrict users to perform only rsync operations, resulting in the execution of arbitrary shell commands.",
"id": "GHSA-vx65-qfv7-jcf4",
"modified": "2022-05-13T01:08:14Z",
"published": "2022-05-13T01:08:14Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2019-3463"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2019/02/msg00007.html"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/HO3MDU3AH5SLYBKHH5PJ6PHC63ASIF42"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/KR2OHTHMJVV4DO3HDRFQQZ5JENHDJQEN"
},
{
"type": "WEB",
"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/T42YYNWJZG422GATWAHAEK4A24OKY557"
},
{
"type": "WEB",
"url": "https://security.gentoo.org/glsa/202007-29"
},
{
"type": "WEB",
"url": "https://tracker.debian.org/news/1026713/accepted-rssh-234-5deb9u2-source-amd64-into-stable-embargoed-stable"
},
{
"type": "WEB",
"url": "https://usn.ubuntu.com/3946-1"
},
{
"type": "WEB",
"url": "https://www.debian.org/security/2019/dsa-4382"
},
{
"type": "WEB",
"url": "http://seclists.org/fulldisclosure/2021/May/78"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/106839"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-W287-4MR4-4V3V
Vulnerability from github – Published: 2024-08-12 21:31 – Updated: 2025-10-22 00:33A vulnerability in the Mitel 6800 Series, 6900 Series, and 6900w Series SIP Phones, including the 6970 Conference Unit, through R6.4.0.HF1 (R6.4.0.136) could allow an authenticated attacker with administrative privilege to conduct an argument injection attack, due to insufficient parameter sanitization during the boot process. A successful exploit could allow an attacker to execute arbitrary commands within the context of the system.
{
"affected": [],
"aliases": [
"CVE-2024-41710"
],
"database_specific": {
"cwe_ids": [
"CWE-88"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-08-12T19:15:16Z",
"severity": "MODERATE"
},
"details": "A vulnerability in the Mitel 6800 Series, 6900 Series, and 6900w Series SIP Phones, including the 6970 Conference Unit, through R6.4.0.HF1 (R6.4.0.136) could allow an authenticated attacker with administrative privilege to conduct an argument injection attack, due to insufficient parameter sanitization during the boot process. A successful exploit could allow an attacker to execute arbitrary commands within the context of the system.",
"id": "GHSA-w287-4mr4-4v3v",
"modified": "2025-10-22T00:33:05Z",
"published": "2024-08-12T21:31:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-41710"
},
{
"type": "WEB",
"url": "https://github.com/kwburns/CVE/blob/main/Mitel/6.3.0.1020/README.md"
},
{
"type": "WEB",
"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-41710"
},
{
"type": "WEB",
"url": "https://www.mitel.com/support/security-advisories"
},
{
"type": "WEB",
"url": "https://www.mitel.com/support/security-advisories/mitel-product-security-advisory-24-0019"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-W46M-W25C-WX2R
Vulnerability from github – Published: 2024-11-13 03:30 – Updated: 2024-11-13 03:30Argument injection in Ivanti Connect Secure before version 22.7R2.1 and 9.1R18.7 and Ivanti Policy Secure before version 22.7R1.1 allows a remote authenticated attacker with admin privileges to achieve remote code execution.
{
"affected": [],
"aliases": [
"CVE-2024-39711"
],
"database_specific": {
"cwe_ids": [
"CWE-88"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-11-13T02:15:19Z",
"severity": "CRITICAL"
},
"details": "Argument injection in Ivanti Connect Secure before version 22.7R2.1 and 9.1R18.7 and Ivanti Policy Secure before version 22.7R1.1 allows a remote authenticated attacker with admin privileges to achieve remote code execution.",
"id": "GHSA-w46m-w25c-wx2r",
"modified": "2024-11-13T03:30:47Z",
"published": "2024-11-13T03:30:47Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-39711"
},
{
"type": "WEB",
"url": "https://forums.ivanti.com/s/article/Security-Advisory-Ivanti-Connect-Secure-ICS-Ivanti-Policy-Secure-IPS-Ivanti-Secure-Access-Client-ISAC-Multiple-CVEs"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-W4W3-5RJF-GVQH
Vulnerability from github – Published: 2022-05-01 06:55 – Updated: 2022-05-01 06:55Argument injection vulnerability in Internet Explorer 6 for Windows XP SP2 allows user-assisted remote attackers to modify command line arguments to an invoked mail client via " (double quote) characters in a mailto: scheme handler, as demonstrated by launching Microsoft Outlook with an arbitrary filename as an attachment. NOTE: it is not clear whether this issue is implementation-specific or a problem in the Microsoft API.
{
"affected": [],
"aliases": [
"CVE-2006-2056"
],
"database_specific": {
"cwe_ids": [
"CWE-88"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2006-04-26T20:06:00Z",
"severity": "MODERATE"
},
"details": "Argument injection vulnerability in Internet Explorer 6 for Windows XP SP2 allows user-assisted remote attackers to modify command line arguments to an invoked mail client via \" (double quote) characters in a mailto: scheme handler, as demonstrated by launching Microsoft Outlook with an arbitrary filename as an attachment. NOTE: it is not clear whether this issue is implementation-specific or a problem in the Microsoft API.",
"id": "GHSA-w4w3-5rjf-gvqh",
"modified": "2022-05-01T06:55:21Z",
"published": "2022-05-01T06:55:21Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2006-2056"
},
{
"type": "WEB",
"url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/26118"
},
{
"type": "WEB",
"url": "http://ingehenriksen.blogspot.com/2006/04/office-2003-file-attachment-exploit.html"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/archive/1/432009/100/0/threaded"
},
{
"type": "WEB",
"url": "http://www.vupen.com/english/advisories/2006/1538"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-W8P5-MX5W-CPQJ
Vulnerability from github – Published: 2026-06-05 09:33 – Updated: 2026-06-30 03:36A flaw was found in ansible-core. The ansible-galaxy role install command processes dependency specifications from a role's meta/requirements.yml file. Due to improper neutralization of argument delimiters, a malicious role author can inject arbitrary git configuration flags through the src field. This allows arbitrary code execution on the machine of a user who installs the role via ansible-galaxy role install.
{
"affected": [],
"aliases": [
"CVE-2026-11332"
],
"database_specific": {
"cwe_ids": [
"CWE-88"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-06-05T09:16:26Z",
"severity": "HIGH"
},
"details": "A flaw was found in ansible-core. The ansible-galaxy role install command processes dependency specifications from a role\u0027s meta/requirements.yml file. Due to improper neutralization of argument delimiters, a malicious role author can inject arbitrary git configuration flags through the src field. This allows arbitrary code execution on the machine of a user who installs the role via ansible-galaxy role install.",
"id": "GHSA-w8p5-mx5w-cpqj",
"modified": "2026-06-30T03:36:55Z",
"published": "2026-06-05T09:33:46Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-11332"
},
{
"type": "WEB",
"url": "https://access.redhat.com/security/cve/CVE-2026-11332"
},
{
"type": "WEB",
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2485379"
},
{
"type": "WEB",
"url": "https://github.com/ansible/ansible"
},
{
"type": "WEB",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-11332.json"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-W8XW-7CRF-H23X
Vulnerability from github – Published: 2022-10-16 12:00 – Updated: 2022-10-21 16:07Gitea before 1.17.3 does not sanitize and escape refs in the git backend. Arguments to git commands are mishandled.
{
"affected": [
{
"package": {
"ecosystem": "Go",
"name": "github.com/go-gitea/gitea"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.17.3"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2022-42968"
],
"database_specific": {
"cwe_ids": [
"CWE-88"
],
"github_reviewed": true,
"github_reviewed_at": "2022-10-21T16:07:23Z",
"nvd_published_at": "2022-10-16T04:15:00Z",
"severity": "CRITICAL"
},
"details": "Gitea before 1.17.3 does not sanitize and escape refs in the git backend. Arguments to git commands are mishandled.",
"id": "GHSA-w8xw-7crf-h23x",
"modified": "2022-10-21T16:07:23Z",
"published": "2022-10-16T12:00:23Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-42968"
},
{
"type": "WEB",
"url": "https://github.com/go-gitea/gitea/pull/21463"
},
{
"type": "PACKAGE",
"url": "https://github.com/go-gitea/gitea"
},
{
"type": "WEB",
"url": "https://github.com/go-gitea/gitea/releases/tag/v1.17.3"
},
{
"type": "WEB",
"url": "https://security.gentoo.org/glsa/202210-14"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "Gitea vulnerable to Argument Injection"
}
GHSA-W99V-7JP5-46GC
Vulnerability from github – Published: 2022-04-30 18:15 – Updated: 2022-04-30 18:15Internet Explorer 5.5 and earlier executes Telnet sessions using command line arguments that are specified by the web site, which could allow remote attackers to execute arbitrary commands if the IE client is using the Telnet client provided in Services for Unix (SFU) 2.0, which creates session transcripts.
{
"affected": [],
"aliases": [
"CVE-2001-0150"
],
"database_specific": {
"cwe_ids": [
"CWE-88"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2001-06-02T04:00:00Z",
"severity": "MODERATE"
},
"details": "Internet Explorer 5.5 and earlier executes Telnet sessions using command line arguments that are specified by the web site, which could allow remote attackers to execute arbitrary commands if the IE client is using the Telnet client provided in Services for Unix (SFU) 2.0, which creates session transcripts.",
"id": "GHSA-w99v-7jp5-46gc",
"modified": "2022-04-30T18:15:30Z",
"published": "2022-04-30T18:15:30Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2001-0150"
},
{
"type": "WEB",
"url": "https://docs.microsoft.com/en-us/security-updates/securitybulletins/2001/ms01-015"
},
{
"type": "WEB",
"url": "https://exchange.xforce.ibmcloud.com/vulnerabilities/6230"
},
{
"type": "WEB",
"url": "http://www.osvdb.org/7816"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/2463"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-W9PM-7CXW-VW6J
Vulnerability from github – Published: 2024-08-27 15:32 – Updated: 2024-08-27 15:32The product allows user input to control or influence paths or file names that are used in filesystem operations, allowing the attacker to access or modify system files or other files that are critical to the application.
{
"affected": [],
"aliases": [
"CVE-2024-3980"
],
"database_specific": {
"cwe_ids": [
"CWE-22",
"CWE-88"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-08-27T13:15:05Z",
"severity": "CRITICAL"
},
"details": "The product allows user input to control or influence paths or file\nnames that are used in filesystem operations, allowing the attacker to access or modify system files or other files that are\ncritical to the application.",
"id": "GHSA-w9pm-7cxw-vw6j",
"modified": "2024-08-27T15:32:47Z",
"published": "2024-08-27T15:32:47Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-3980"
},
{
"type": "WEB",
"url": "https://publisher.hitachienergy.com/preview?DocumentID=8DBD000160\u0026LanguageCode=en\u0026DocumentPartId=\u0026Action=Launch"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Mitigation
Strategy: Parameterization
Where possible, avoid building a single string that contains the command and its arguments. Some languages or frameworks have functions that support specifying independent arguments, e.g. as an array, which is used to automatically perform the appropriate quoting or escaping while building the command. For example, in PHP, escapeshellarg() can be used to escape a single argument to system(), or exec() can be called with an array of arguments. In C, code can often be refactored from using system() - which accepts a single string - to using exec(), which requires separate function arguments for each parameter.
Mitigation
Strategy: Input Validation
Understand all the potential areas where untrusted inputs can enter your product: parameters or arguments, cookies, anything read from the network, environment variables, request headers as well as content, URL components, e-mail, files, databases, and any external systems that provide data to the application. Perform input validation at well-defined interfaces.
Mitigation MIT-5
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.
Mitigation
Directly convert your input type into the expected data type, such as using a conversion function that translates a string into a number. After converting to the expected data type, ensure that the input's values fall within the expected range of allowable values and that multi-field consistencies are maintained.
Mitigation
- Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180, CWE-181). Make sure that your application does not inadvertently decode the same input twice (CWE-174). Such errors could be used to bypass allowlist schemes by introducing dangerous inputs after they have been checked. Use libraries such as the OWASP ESAPI Canonicalization control.
- Consider performing repeated canonicalization until your input does not change any more. This will avoid double-decoding and similar scenarios, but it might inadvertently modify inputs that are allowed to contain properly-encoded dangerous content.
Mitigation
When exchanging data between components, ensure that both components are using the same character encoding. Ensure that the proper encoding is applied at each interface. Explicitly set the encoding you are using whenever the protocol allows you to do so.
Mitigation
When your application combines data from multiple sources, perform the validation after the sources have been combined. The individual data elements may pass the validation step but violate the intended restrictions after they have been combined.
Mitigation
Use dynamic tools and techniques that interact with the product using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The product's operation may slow down, but it should not become unstable, crash, or generate incorrect results.
CAPEC-137: Parameter Injection
An adversary manipulates the content of request parameters for the purpose of undermining the security of the target. Some parameter encodings use text characters as separators. For example, parameters in a HTTP GET message are encoded as name-value pairs separated by an ampersand (&). If an attacker can supply text strings that are used to fill in these parameters, then they can inject special characters used in the encoding scheme to add or modify parameters. For example, if user input is fed directly into an HTTP GET request and the user provides the value "myInput&new_param=myValue", then the input parameter is set to myInput, but a new parameter (new_param) is also added with a value of myValue. This can significantly change the meaning of the query that is processed by the server. Any encoding scheme where parameters are identified and separated by text characters is potentially vulnerable to this attack - the HTTP GET encoding used above is just one example.
CAPEC-174: Flash Parameter Injection
An adversary takes advantage of improper data validation to inject malicious global parameters into a Flash file embedded within an HTML document. Flash files can leverage user-submitted data to configure the Flash document and access the embedding HTML document.
CAPEC-41: Using Meta-characters in E-mail Headers to Inject Malicious Payloads
This type of attack involves an attacker leveraging meta-characters in email headers to inject improper behavior into email programs. Email software has become increasingly sophisticated and feature-rich. In addition, email applications are ubiquitous and connected directly to the Web making them ideal targets to launch and propagate attacks. As the user demand for new functionality in email applications grows, they become more like browsers with complex rendering and plug in routines. As more email functionality is included and abstracted from the user, this creates opportunities for attackers. Virtually all email applications do not list email header information by default, however the email header contains valuable attacker vectors for the attacker to exploit particularly if the behavior of the email client application is known. Meta-characters are hidden from the user, but can contain scripts, enumerations, probes, and other attacks against the user's system.
CAPEC-460: HTTP Parameter Pollution (HPP)
An adversary adds duplicate HTTP GET/POST parameters by injecting query string delimiters. Via HPP it may be possible to override existing hardcoded HTTP parameters, modify the application behaviors, access and, potentially exploit, uncontrollable variables, and bypass input validation checkpoints and WAF rules.
CAPEC-88: OS Command Injection
In this type of an attack, an adversary injects operating system commands into existing application functions. An application that uses untrusted input to build command strings is vulnerable. An adversary can leverage OS command injection in an application to elevate privileges, execute arbitrary commands and compromise the underlying operating system.