CWE-94
Allowed-with-ReviewImproper Control of Generation of Code ('Code Injection')
Abstraction: Base · Status: Draft
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
8310 vulnerabilities reference this CWE, most recent first.
GHSA-VWRP-X96C-MHWQ
Vulnerability from github – Published: 2026-05-07 04:07 – Updated: 2026-05-14 20:36Summary
vm2's bridge exposes mutable proxies for real host-realm intrinsic prototypes and then forwards sandbox writes into the underlying host objects with otherReflectSet() and otherReflectDefineProperty(), which lets attacker-controlled JavaScript running in a default VM or inherited NodeVM mutate shared host Object.prototype, Array.prototype, and Function.prototype from inside the sandbox.
Details
BaseHandler.apply() unwraps sandbox-controlled receivers and arguments with otherFromThis() / otherFromThisArguments() and then directly invokes the real host function with ret = otherReflectApply(object, context, args), so any default-exposed host function that can surface a prototype getter becomes a prototype-walking primitive (lib/bridge.js:665-676). BaseHandler.get() special-cases proto and returns the host-side descriptor or proxy target prototype, which is enough for the attacker to reuse the host lookupGetter('proto') accessor repeatedly until the walk lands on host Object.prototype, Array.prototype, or Function.prototype (lib/bridge.js:590-616). Once the attacker has a proxy to a host intrinsic prototype, BaseHandler.set() performs value = otherFromThis(value); return otherReflectSet(object, key, value) === true;, which writes attacker-controlled data directly into the shared host object instead of keeping the mutation sandbox-local; BaseHandler.defineProperty() repeats the same design at otherReflectDefineProperty(object, prop, otherDesc) for descriptor-based writes (lib/bridge.js:641-649, lib/bridge.js:753-774). Existing validation does not stop the attack because the constructor filter only blocks one dangerous-property access pattern, setPrototypeOf() only blocks prototype replacement rather than ordinary property assignment, and containsDangerousConstructor() only protects one later re-unwrapping path instead of the initial host-prototype write sink (lib/bridge.js:494-530, lib/bridge.js:595-610, lib/bridge.js:660-662).
PoC
Run the following code snippet and observe that the value of vm2EscapeMarker is polluted:
const { VM } = require('vm2');
const vm = new VM();
vm.run(`
const g = ({}).__lookupGetter__;
const a = Buffer.apply;
const p = a.apply(g, [Buffer, ['__proto__']]);
const hostObjectProto = p.call(p.call(p.call(p.call(Buffer.of()))));
hostObjectProto.vm2EscapeMarker = 'polluted-object-prototype';
`);
console.log({}.vm2EscapeMarker)
Impact
Sandbox escape and prototype pollution.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 3.10.5"
},
"package": {
"ecosystem": "npm",
"name": "vm2"
},
"ranges": [
{
"events": [
{
"introduced": "3.9.6"
},
{
"fixed": "3.11.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-44005"
],
"database_specific": {
"cwe_ids": [
"CWE-1321",
"CWE-94"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-07T04:07:05Z",
"nvd_published_at": "2026-05-13T18:16:17Z",
"severity": "CRITICAL"
},
"details": "### Summary\nvm2\u0027s bridge exposes mutable proxies for real host-realm intrinsic prototypes and then forwards sandbox writes into the underlying host objects with otherReflectSet() and otherReflectDefineProperty(), which lets attacker-controlled JavaScript running in a default VM or inherited NodeVM mutate shared host Object.prototype, Array.prototype, and Function.prototype from inside the sandbox.\n\n### Details\nBaseHandler.apply() unwraps sandbox-controlled receivers and arguments with otherFromThis() / otherFromThisArguments() and then directly invokes the real host function with ret = otherReflectApply(object, context, args), so any default-exposed host function that can surface a prototype getter becomes a prototype-walking primitive ([lib/bridge.js:665-676](https://github.com/patriksimek/vm2/blob/408fc855f1cc1bbc2985b029465ee0e732ada433/lib/bridge.js#L665-L676)). BaseHandler.get() special-cases __proto__ and returns the host-side descriptor or proxy target prototype, which is enough for the attacker to reuse the host __lookupGetter__(\u0027__proto__\u0027) accessor repeatedly until the walk lands on host Object.prototype, Array.prototype, or Function.prototype ([lib/bridge.js:590-616](https://github.com/patriksimek/vm2/blob/408fc855f1cc1bbc2985b029465ee0e732ada433/lib/bridge.js#L590-L616)). Once the attacker has a proxy to a host intrinsic prototype, BaseHandler.set() performs value = otherFromThis(value); return otherReflectSet(object, key, value) === true;, which writes attacker-controlled data directly into the shared host object instead of keeping the mutation sandbox-local; BaseHandler.defineProperty() repeats the same design at otherReflectDefineProperty(object, prop, otherDesc) for descriptor-based writes ([lib/bridge.js:641-649](https://github.com/patriksimek/vm2/blob/408fc855f1cc1bbc2985b029465ee0e732ada433/lib/bridge.js#L641-L649), [lib/bridge.js:753-774](https://github.com/patriksimek/vm2/blob/408fc855f1cc1bbc2985b029465ee0e732ada433/lib/bridge.js#L753-L774)). Existing validation does not stop the attack because the constructor filter only blocks one dangerous-property access pattern, setPrototypeOf() only blocks prototype replacement rather than ordinary property assignment, and containsDangerousConstructor() only protects one later re-unwrapping path instead of the initial host-prototype write sink ([lib/bridge.js:494-530](https://github.com/patriksimek/vm2/blob/408fc855f1cc1bbc2985b029465ee0e732ada433/lib/bridge.js#L494-L530), [lib/bridge.js:595-610](https://github.com/patriksimek/vm2/blob/408fc855f1cc1bbc2985b029465ee0e732ada433/lib/bridge.js#L595-L610), [lib/bridge.js:660-662](https://github.com/patriksimek/vm2/blob/408fc855f1cc1bbc2985b029465ee0e732ada433/lib/bridge.js#L660-L662)).\n\n### PoC\nRun the following code snippet and observe that the value of vm2EscapeMarker is polluted:\n```\nconst { VM } = require(\u0027vm2\u0027);\nconst vm = new VM();\nvm.run(`\n const g = ({}).__lookupGetter__;\n const a = Buffer.apply;\n const p = a.apply(g, [Buffer, [\u0027__proto__\u0027]]);\n const hostObjectProto = p.call(p.call(p.call(p.call(Buffer.of()))));\n hostObjectProto.vm2EscapeMarker = \u0027polluted-object-prototype\u0027;\n`);\nconsole.log({}.vm2EscapeMarker)\n```\n\n### Impact\nSandbox escape and prototype pollution.",
"id": "GHSA-vwrp-x96c-mhwq",
"modified": "2026-05-14T20:36:31Z",
"published": "2026-05-07T04:07:05Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/patriksimek/vm2/security/advisories/GHSA-vwrp-x96c-mhwq"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44005"
},
{
"type": "PACKAGE",
"url": "https://github.com/patriksimek/vm2"
},
{
"type": "WEB",
"url": "https://github.com/patriksimek/vm2/releases/tag/v3.11.0"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "vm2: Mutable Proxies for Host Intrinsic Prototypes Allows Sandbox Escape"
}
GHSA-VWRR-Q8R4-3HGF
Vulnerability from github – Published: 2022-05-14 01:35 – Updated: 2024-10-17 15:31In the Automattic WooCommerce plugin before 3.2.4 for WordPress, an attack is possible after gaining access to the target site with a user account that has at least Shop manager privileges. The attacker then constructs a specifically crafted string that will turn into a PHP object injection involving the includes/shortcodes/class-wc-shortcode-products.php WC_Shortcode_Products::get_products() use of cached queries within shortcodes.
{
"affected": [],
"aliases": [
"CVE-2017-18356"
],
"database_specific": {
"cwe_ids": [
"CWE-94"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2019-01-15T16:29:00Z",
"severity": "HIGH"
},
"details": "In the Automattic WooCommerce plugin before 3.2.4 for WordPress, an attack is possible after gaining access to the target site with a user account that has at least Shop manager privileges. The attacker then constructs a specifically crafted string that will turn into a PHP object injection involving the includes/shortcodes/class-wc-shortcode-products.php WC_Shortcode_Products::get_products() use of cached queries within shortcodes.",
"id": "GHSA-vwrr-q8r4-3hgf",
"modified": "2024-10-17T15:31:05Z",
"published": "2022-05-14T01:35:48Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2017-18356"
},
{
"type": "WEB",
"url": "https://blog.ripstech.com/2018/woocommerce-php-object-injection"
},
{
"type": "WEB",
"url": "https://woocommerce.wordpress.com/2017/11/16/woocommerce-3-2-4-security-fix-release-notes"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-VWV5-32VR-3JCP
Vulnerability from github – Published: 2026-07-10 15:31 – Updated: 2026-07-10 15:31PraisonAI versions before 4.6.78 contain a code injection vulnerability in deploy/api.py where the agents_file parameter is directly interpolated into an f-string without sanitization. Attackers can inject arbitrary Python code that executes when the generated server code runs via subprocess.Popen().
{
"affected": [],
"aliases": [
"CVE-2026-61444"
],
"database_specific": {
"cwe_ids": [
"CWE-94"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-10T15:16:50Z",
"severity": "CRITICAL"
},
"details": "PraisonAI versions before 4.6.78 contain a code injection vulnerability in deploy/api.py where the agents_file parameter is directly interpolated into an f-string without sanitization. Attackers can inject arbitrary Python code that executes when the generated server code runs via subprocess.Popen().",
"id": "GHSA-vwv5-32vr-3jcp",
"modified": "2026-07-10T15:31:42Z",
"published": "2026-07-10T15:31:42Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-g6j7-pffp-8whg"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-61444"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/praisonai-before-code-injection-via-f-string"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/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-VX3M-4GQ6-768W
Vulnerability from github – Published: 2022-05-24 19:20 – Updated: 2023-12-28 18:303D Viewer Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-43209.
{
"affected": [],
"aliases": [
"CVE-2021-43208"
],
"database_specific": {
"cwe_ids": [
"CWE-94"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-11-10T01:19:00Z",
"severity": "HIGH"
},
"details": "3D Viewer Remote Code Execution Vulnerability This CVE ID is unique from CVE-2021-43209.",
"id": "GHSA-vx3m-4gq6-768w",
"modified": "2023-12-28T18:30:31Z",
"published": "2022-05-24T19:20:20Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-43208"
},
{
"type": "WEB",
"url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-43208"
}
],
"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-VX5C-87QX-CV6C
Vulnerability from github – Published: 2017-12-18 22:27 – Updated: 2021-06-10 20:06math.js before 3.17.0 had an arbitrary code execution in the JavaScript engine. Creating a typed function with JavaScript code in the name could result arbitrary execution.
Recommendation
Update to version 3.17.0 or later.
{
"affected": [
{
"package": {
"ecosystem": "npm",
"name": "mathjs"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "3.17.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2017-1001002"
],
"database_specific": {
"cwe_ids": [
"CWE-94"
],
"github_reviewed": true,
"github_reviewed_at": "2020-06-16T21:58:44Z",
"nvd_published_at": null,
"severity": "CRITICAL"
},
"details": "math.js before 3.17.0 had an arbitrary code execution in the JavaScript engine. Creating a typed function with JavaScript code in the name could result arbitrary execution.\n\n\n## Recommendation\n\nUpdate to version 3.17.0 or later.",
"id": "GHSA-vx5c-87qx-cv6c",
"modified": "2021-06-10T20:06:12Z",
"published": "2017-12-18T22:27:45Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2017-1001002"
},
{
"type": "WEB",
"url": "https://github.com/josdejong/mathjs/commit/8d2d48d81b3c233fb64eb2ec1d7a9e1cf6a55a90"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-vx5c-87qx-cv6c"
},
{
"type": "WEB",
"url": "https://github.com/josdejong/mathjs/blob/master/HISTORY.md#2017-11-18-version-3170"
},
{
"type": "WEB",
"url": "https://www.npmjs.com/advisories/552"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "Arbitrary Code Execution in mathjs"
}
GHSA-VX8F-8JQH-8XQR
Vulnerability from github – Published: 2022-05-01 18:30 – Updated: 2022-05-01 18:30The embedded Internet Explorer server control in AOL Instant Messenger (AIM) 6.5.3.12 and earlier allows remote attackers to execute arbitrary code via unspecified web script or HTML in an instant message, related to AIM's filtering of "specific tags and attributes" and the lack of Local Machine Zone lockdown. NOTE: this issue reportedly exists because of an incomplete fix for CVE-2007-4901.
{
"affected": [],
"aliases": [
"CVE-2007-5124"
],
"database_specific": {
"cwe_ids": [
"CWE-94"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2007-09-27T19:17:00Z",
"severity": "MODERATE"
},
"details": "The embedded Internet Explorer server control in AOL Instant Messenger (AIM) 6.5.3.12 and earlier allows remote attackers to execute arbitrary code via unspecified web script or HTML in an instant message, related to AIM\u0027s filtering of \"specific tags and attributes\" and the lack of Local Machine Zone lockdown. NOTE: this issue reportedly exists because of an incomplete fix for CVE-2007-4901.",
"id": "GHSA-vx8f-8jqh-8xqr",
"modified": "2022-05-01T18:30:18Z",
"published": "2022-05-01T18:30:18Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2007-5124"
},
{
"type": "WEB",
"url": "http://aviv.raffon.net/2007/09/25/ReadyAIMFire.aspx"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/archive/1/480647/100/0/threaded"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-VX8G-76PM-2X2X
Vulnerability from github – Published: 2024-02-20 00:30 – Updated: 2025-09-30 21:31Loomio version 2.22.0 allows executing arbitrary commands on the server.
This is possible because the application is vulnerable to OS Command Injection.
{
"affected": [],
"aliases": [
"CVE-2024-1297"
],
"database_specific": {
"cwe_ids": [
"CWE-78",
"CWE-94"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-02-20T00:15:14Z",
"severity": "CRITICAL"
},
"details": "Loomio version 2.22.0 allows executing arbitrary commands on the server.\n\nThis is possible because the application is vulnerable to OS Command Injection.",
"id": "GHSA-vx8g-76pm-2x2x",
"modified": "2025-09-30T21:31:15Z",
"published": "2024-02-20T00:30:37Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-1297"
},
{
"type": "WEB",
"url": "https://github.com/loomio/loomio/commit/6bc5429bfb5a9c7c811a4487d97ea54a8b23a0fa#diff-b9a7e6b3dfb0fd855c11198a7c53e6f6f90945f28c78cc5dbd960d04d5d28203"
},
{
"type": "WEB",
"url": "https://fluidattacks.com/advisories/stones"
},
{
"type": "WEB",
"url": "https://github.com/loomio/loomio"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-VXF2-FQVQ-W7P7
Vulnerability from github – Published: 2022-05-02 03:58 – Updated: 2022-05-02 03:58Multiple PHP remote file inclusion vulnerabilities in the MojoBlog component RC 0.15 for Joomla! allow remote attackers to execute arbitrary PHP code via a URL in the mosConfig_absolute_path parameter to (1) wp-comments-post.php and (2) wp-trackback.php.
{
"affected": [],
"aliases": [
"CVE-2009-4789"
],
"database_specific": {
"cwe_ids": [
"CWE-94"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2010-04-21T14:30:00Z",
"severity": "HIGH"
},
"details": "Multiple PHP remote file inclusion vulnerabilities in the MojoBlog component RC 0.15 for Joomla! allow remote attackers to execute arbitrary PHP code via a URL in the mosConfig_absolute_path parameter to (1) wp-comments-post.php and (2) wp-trackback.php.",
"id": "GHSA-vxf2-fqvq-w7p7",
"modified": "2022-05-02T03:58:15Z",
"published": "2022-05-02T03:58:15Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2009-4789"
},
{
"type": "WEB",
"url": "http://packetstormsecurity.org/0912-exploits/joomlamojoblog-rfi.txt"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/37179"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-VXF7-7C9G-M3X8
Vulnerability from github – Published: 2026-06-25 06:30 – Updated: 2026-06-25 06:30GitLab has remediated an issue in GitLab CE/EE affecting all versions from 14.8 before 18.11.6, 19.0 before 19.0.3, and 19.1 before 19.1.1 that under certain conditions could have allowed an authenticated user to conceal content within a Snippet due to improper input validation.
{
"affected": [],
"aliases": [
"CVE-2026-1606"
],
"database_specific": {
"cwe_ids": [
"CWE-94"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-06-25T05:16:52Z",
"severity": "MODERATE"
},
"details": "GitLab has remediated an issue in GitLab CE/EE affecting all versions from 14.8 before 18.11.6, 19.0 before 19.0.3, and 19.1 before 19.1.1 that under certain conditions could have allowed an authenticated user to conceal content within a Snippet due to improper input validation.",
"id": "GHSA-vxf7-7c9g-m3x8",
"modified": "2026-06-25T06:30:42Z",
"published": "2026-06-25T06:30:42Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-1606"
},
{
"type": "WEB",
"url": "https://hackerone.com/reports/3527473"
},
{
"type": "WEB",
"url": "https://docs.gitlab.com/releases/patches/patch-release-gitlab-19-1-1-released"
},
{
"type": "WEB",
"url": "https://gitlab.com/gitlab-org/gitlab/-/work_items/588128"
}
],
"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"
}
]
}
GHSA-VXF7-PJJ6-WH93
Vulnerability from github – Published: 2026-02-20 18:31 – Updated: 2026-02-27 18:31Improper Control of Generation of Code ('Code Injection') vulnerability in WesternDeal WPForms Google Sheet Connector gsheetconnector-wpforms allows Code Injection.This issue affects WPForms Google Sheet Connector: from n/a through <= 4.0.1.
{
"affected": [],
"aliases": [
"CVE-2025-67979"
],
"database_specific": {
"cwe_ids": [
"CWE-94"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-02-20T16:22:04Z",
"severity": "CRITICAL"
},
"details": "Improper Control of Generation of Code (\u0027Code Injection\u0027) vulnerability in WesternDeal WPForms Google Sheet Connector gsheetconnector-wpforms allows Code Injection.This issue affects WPForms Google Sheet Connector: from n/a through \u003c= 4.0.1.",
"id": "GHSA-vxf7-pjj6-wh93",
"modified": "2026-02-27T18:31:01Z",
"published": "2026-02-20T18:31:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-67979"
},
{
"type": "WEB",
"url": "https://patchstack.com/database/Wordpress/Plugin/gsheetconnector-wpforms/vulnerability/wordpress-wpforms-google-sheet-connector-plugin-4-0-1-remote-code-execution-rce-vulnerability?_s_id=cve"
}
],
"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: Refactoring
Refactor your program so that you do not have to dynamically generate code.
Mitigation
- Run your code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which code can be executed by your product.
- Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection.
- This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise.
- Be careful to avoid CWE-243 and other weaknesses related to jails.
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.
- To reduce the likelihood of code injection, use stringent allowlists that limit which constructs are allowed. If you are dynamically constructing code that invokes a function, then verifying that the input is alphanumeric might be insufficient. An attacker might still be able to reference a dangerous function that you did not intend to allow, such as system(), exec(), or exit().
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.
Mitigation MIT-32
Strategy: Compilation or Build Hardening
Run the code in an environment that performs automatic taint propagation and prevents any command execution that uses tainted variables, such as Perl's "-T" switch. This will force the program to perform validation steps that remove the taint, although you must be careful to correctly validate your inputs so that you do not accidentally mark dangerous inputs as untainted (see CWE-183 and CWE-184).
Mitigation MIT-32
Strategy: Environment Hardening
Run the code in an environment that performs automatic taint propagation and prevents any command execution that uses tainted variables, such as Perl's "-T" switch. This will force the program to perform validation steps that remove the taint, although you must be careful to correctly validate your inputs so that you do not accidentally mark dangerous inputs as untainted (see CWE-183 and CWE-184).
Mitigation
For Python programs, it is frequently encouraged to use the ast.literal_eval() function instead of eval, since it is intentionally designed to avoid executing code. However, an adversary could still cause excessive memory or stack consumption via deeply nested structures [REF-1372], so the python documentation discourages use of ast.literal_eval() on untrusted data [REF-1373].
CAPEC-242: Code Injection
An adversary exploits a weakness in input validation on the target to inject new code into that which is currently executing. This differs from code inclusion in that code inclusion involves the addition or replacement of a reference to a code file, which is subsequently loaded by the target and used as part of the code of some application.
CAPEC-35: Leverage Executable Code in Non-Executable Files
An attack of this type exploits a system's trust in configuration and resource files. When the executable loads the resource (such as an image file or configuration file) the attacker has modified the file to either execute malicious code directly or manipulate the target process (e.g. application server) to execute based on the malicious configuration parameters. Since systems are increasingly interrelated mashing up resources from local and remote sources the possibility of this attack occurring is high.
CAPEC-77: Manipulating User-Controlled Variables
This attack targets user controlled variables (DEBUG=1, PHP Globals, and So Forth). An adversary can override variables leveraging user-supplied, untrusted query variables directly used on the application server without any data sanitization. In extreme cases, the adversary can change variables controlling the business logic of the application. For instance, in languages like PHP, a number of poorly set default configurations may allow the user to override variables.