CWE-78
AllowedImproper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Abstraction: Base · Status: Stable
The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.
8322 vulnerabilities reference this CWE, most recent first.
GHSA-G8HX-765H-VXCC
Vulnerability from github – Published: 2021-12-23 00:01 – Updated: 2022-04-20 00:02A specially-crafted HTTP request can lead to arbitrary command execution in DSA keypasswd parameter. An attacker can make an authenticated HTTP request to trigger this vulnerability.
{
"affected": [],
"aliases": [
"CVE-2021-21874"
],
"database_specific": {
"cwe_ids": [
"CWE-78"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2021-12-22T19:15:00Z",
"severity": "CRITICAL"
},
"details": "A specially-crafted HTTP request can lead to arbitrary command execution in DSA keypasswd parameter. An attacker can make an authenticated HTTP request to trigger this vulnerability.",
"id": "GHSA-g8hx-765h-vxcc",
"modified": "2022-04-20T00:02:02Z",
"published": "2021-12-23T00:01:20Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-21874"
},
{
"type": "WEB",
"url": "https://talosintelligence.com/vulnerability_reports/TALOS-2021-1314"
}
],
"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"
}
]
}
GHSA-G8Q7-J99F-7V7M
Vulnerability from github – Published: 2022-05-14 03:38 – Updated: 2022-05-14 03:38Ruckus Networks Unleashed AP firmware releases before 200.6.10.1.x and Ruckus Networks Zone Director firmware releases 10.1.0.0.x, 9.10.2.0.x, 9.12.3.0.x, 9.13.3.0.x, 10.0.1.0.x or before contain authenticated Root Command Injection in the CLI that could allow authenticated valid users to execute privileged commands on the respective systems.
{
"affected": [],
"aliases": [
"CVE-2017-6229"
],
"database_specific": {
"cwe_ids": [
"CWE-78"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2018-02-14T19:29:00Z",
"severity": "HIGH"
},
"details": "Ruckus Networks Unleashed AP firmware releases before 200.6.10.1.x and Ruckus Networks Zone Director firmware releases 10.1.0.0.x, 9.10.2.0.x, 9.12.3.0.x, 9.13.3.0.x, 10.0.1.0.x or before contain authenticated Root Command Injection in the CLI that could allow authenticated valid users to execute privileged commands on the respective systems.",
"id": "GHSA-g8q7-j99f-7v7m",
"modified": "2022-05-14T03:38:48Z",
"published": "2022-05-14T03:38:48Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2017-6229"
},
{
"type": "WEB",
"url": "https://ruckus-www.s3.amazonaws.com/pdf/security/faq-security-advisory-id-20180202-v1.0.txt"
}
],
"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-G8R9-G2V8-JV6F
Vulnerability from github – Published: 2026-03-06 16:43 – Updated: 2026-03-13 16:03Summary
A security vulnerability has been identified in GitHub Copilot CLI's shell tool that could allow arbitrary code execution through crafted bash parameter expansion patterns. An attacker who can influence the commands executed by the agent (e.g., via prompt injection through repository files, MCP server responses, or user instructions) can exploit bash parameter transformation operators to execute hidden commands, bypassing the safety assessment that classifies commands as "read-only."
Details
The vulnerability stems from how the CLI's shell safety assessment evaluates commands before execution. The safety layer parses and classifies shell commands as either read-only (safe) or write-capable (requires user approval). However, several bash parameter expansion features can embed executable code within arguments to otherwise read-only commands, causing them to appear safe while actually performing arbitrary operations.
The specific dangerous patterns are:
-
${var@P}— Prompt expansion: The@Pparameter transformation operator evaluates its value as a prompt string, which interprets embedded command substitutions. This allows hidden command execution inside what appears to be a simple variable reference. -
${var=value}/${var:=value}— Assignment side-effects: These forms assign values to variables as a side-effect of expansion. When chained with@P, an attacker can progressively build up a command substitution string across multiple expansions. -
${!var}— Indirect expansion: Dereferences an arbitrary variable name, which can be combined with other patterns to construct and execute commands dynamically. -
Nested
$(cmd)or<(cmd)inside${...}expansions: Command substitution or process substitution embedded within parameter expansion default values (e.g.,${HOME:-$(whoami)}) executes the nested command.
Proof of Concept
The following command appears to run a harmless echo, but actually executes touch /tmp/pwned through chained parameter expansion:
echo ${a="$"}${b="$a(touch /tmp/pwned)"}${b@P}
How it works:
- ${a="$"} assigns the literal $ character to variable a
- ${b="$a(touch /tmp/pwned)"} expands $a to $, constructing the string $(touch /tmp/pwned) and assigning it to b
- ${b@P} applies prompt expansion to b, which evaluates the embedded $(touch /tmp/pwned) command substitution
Prior to the fix, the safety assessment would classify echo as a read-only command and allow execution without user confirmation — even in modes that normally require approval for write operations.
Impact
An attacker who can influence command text sent to the shell tool — for example, through: - Prompt injection via malicious repository content (README files, code comments, issue bodies) - Compromised or malicious MCP server responses - Crafted user instructions containing obfuscated commands
— could achieve arbitrary code execution on the user's workstation. This is possible even in permission modes that require user approval for write operations, since the commands can appear to be using only read-only utilities to ultimately trigger write operations.
Successful exploitation could lead to data exfiltration, file modification, or further system compromise.
Affected Versions
- GitHub Copilot CLI versions prior to 0.0.423
Remediation and Mitigation
Fix
The fix adds three layers of defense:
-
Parse-time detection: The shell safety assessment analyzes
${...}expansion nodes within bash commands, detecting dangerous operators (@P,=,:=,!) and nested command/process substitutions. Commands containing these patterns are downgraded from read-only to write-capable, ensuring they require user approval. -
Unconditional blocking: Commands with dangerous expansion patterns are unconditionally blocked at the tool execution layer — regardless of permission mode (including
--yolo/ autopilot). This prevents exploitation even when all commands are auto-approved. -
System prompt hardening: The bash shell tool's system prompt now includes explicit instructions for the LLM to refuse executing commands with these patterns, providing a defense-in-depth layer.
User Actions
- Upgrade GitHub Copilot CLI to 0.0.423 or later.
- Exercise caution when working in untrusted repositories or with untrusted MCP servers.
- Review any shell commands suggested by the agent that contain complex parameter expansion patterns.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 0.0.422"
},
"package": {
"ecosystem": "npm",
"name": "@github/copilot"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.0.423"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-29783"
],
"database_specific": {
"cwe_ids": [
"CWE-78"
],
"github_reviewed": true,
"github_reviewed_at": "2026-03-06T16:43:31Z",
"nvd_published_at": "2026-03-06T17:16:35Z",
"severity": "HIGH"
},
"details": "## Summary\n\nA security vulnerability has been identified in GitHub Copilot CLI\u0027s shell tool that could allow arbitrary code execution through crafted bash parameter expansion patterns. An attacker who can influence the commands executed by the agent (e.g., via prompt injection through repository files, MCP server responses, or user instructions) can exploit bash parameter transformation operators to execute hidden commands, bypassing the safety assessment that classifies commands as \"read-only.\"\n\n## Details\n\nThe vulnerability stems from how the CLI\u0027s shell safety assessment evaluates commands before execution. The safety layer parses and classifies shell commands as either read-only (safe) or write-capable (requires user approval). However, several bash parameter expansion features can embed executable code within arguments to otherwise read-only commands, causing them to appear safe while actually performing arbitrary operations.\n\nThe specific dangerous patterns are:\n\n1. **`${var@P}` \u2014 Prompt expansion:** The `@P` parameter transformation operator evaluates its value as a prompt string, which interprets embedded command substitutions. This allows hidden command execution inside what appears to be a simple variable reference.\n\n2. **`${var=value}` / `${var:=value}` \u2014 Assignment side-effects:** These forms assign values to variables as a side-effect of expansion. When chained with `@P`, an attacker can progressively build up a command substitution string across multiple expansions.\n\n3. **`${!var}` \u2014 Indirect expansion:** Dereferences an arbitrary variable name, which can be combined with other patterns to construct and execute commands dynamically.\n\n4. **Nested `$(cmd)` or `\u003c(cmd)` inside `${...}` expansions:** Command substitution or process substitution embedded within parameter expansion default values (e.g., `${HOME:-$(whoami)}`) executes the nested command.\n\n### Proof of Concept\n\nThe following command appears to run a harmless `echo`, but actually executes `touch /tmp/pwned` through chained parameter expansion:\n\n```bash\necho ${a=\"$\"}${b=\"$a(touch /tmp/pwned)\"}${b@P}\n```\n\n**How it works:**\n- `${a=\"$\"}` assigns the literal `$` character to variable `a`\n- `${b=\"$a(touch /tmp/pwned)\"}` expands `$a` to `$`, constructing the string `$(touch /tmp/pwned)` and assigning it to `b`\n- `${b@P}` applies prompt expansion to `b`, which evaluates the embedded `$(touch /tmp/pwned)` command substitution\n\nPrior to the fix, the safety assessment would classify `echo` as a read-only command and allow execution without user confirmation \u2014 even in modes that normally require approval for write operations.\n\n## Impact\n\nAn attacker who can influence command text sent to the shell tool \u2014 for example, through:\n- Prompt injection via malicious repository content (README files, code comments, issue bodies)\n- Compromised or malicious MCP server responses\n- Crafted user instructions containing obfuscated commands\n\n\u2014 could achieve arbitrary code execution on the user\u0027s workstation. This is possible even in permission modes that require user approval for write operations, since the commands can appear to be using only read-only utilities to ultimately trigger write operations.\n\nSuccessful exploitation could lead to data exfiltration, file modification, or further system compromise.\n\n## Affected Versions\n\n- GitHub Copilot CLI versions prior to 0.0.423\n\n## Remediation and Mitigation\n\n### Fix\n\nThe fix adds three layers of defense:\n\n1. **Parse-time detection:** The shell safety assessment analyzes `${...}` expansion nodes within bash commands, detecting dangerous operators (`@P`, `=`, `:=`, `!`) and nested command/process substitutions. Commands containing these patterns are downgraded from read-only to write-capable, ensuring they require user approval.\n\n2. **Unconditional blocking:** Commands with dangerous expansion patterns are unconditionally blocked at the tool execution layer \u2014 regardless of permission mode (including `--yolo` / autopilot). This prevents exploitation even when all commands are auto-approved.\n\n3. **System prompt hardening:** The bash shell tool\u0027s system prompt now includes explicit instructions for the LLM to refuse executing commands with these patterns, providing a defense-in-depth layer.\n\n### User Actions\n\n1. **Upgrade** GitHub Copilot CLI to **0.0.423** or later.\n2. **Exercise caution** when working in untrusted repositories or with untrusted MCP servers.\n3. **Review** any shell commands suggested by the agent that contain complex parameter expansion patterns.",
"id": "GHSA-g8r9-g2v8-jv6f",
"modified": "2026-03-13T16:03:33Z",
"published": "2026-03-06T16:43:31Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/github/copilot-cli/security/advisories/GHSA-g8r9-g2v8-jv6f"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-29783"
},
{
"type": "PACKAGE",
"url": "https://github.com/github/copilot-cli"
},
{
"type": "WEB",
"url": "https://github.com/github/copilot-cli/releases/tag/v0.0.423"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
"type": "CVSS_V4"
}
],
"summary": "GitHub Copilot CLI Dangerous Shell Expansion Patterns Enable Arbitrary Code Execution"
}
GHSA-G8WW-FC2W-QFRG
Vulnerability from github – Published: 2022-05-13 01:35 – Updated: 2022-05-13 01:35A vulnerability in the web-based UI of Cisco IP Phone 6800, 7800, and 8800 Series with Multiplatform Firmware before 11.2(1) could allow an authenticated, remote attacker to perform a command injection and execute commands with the privileges of the web server. The vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by including arbitrary shell commands in a specific user input field. Cisco Bug IDs: CSCvi51426.
{
"affected": [],
"aliases": [
"CVE-2018-0341"
],
"database_specific": {
"cwe_ids": [
"CWE-78"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2018-07-16T17:29:00Z",
"severity": "HIGH"
},
"details": "A vulnerability in the web-based UI of Cisco IP Phone 6800, 7800, and 8800 Series with Multiplatform Firmware before 11.2(1) could allow an authenticated, remote attacker to perform a command injection and execute commands with the privileges of the web server. The vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by including arbitrary shell commands in a specific user input field. Cisco Bug IDs: CSCvi51426.",
"id": "GHSA-g8ww-fc2w-qfrg",
"modified": "2022-05-13T01:35:22Z",
"published": "2022-05-13T01:35:22Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2018-0341"
},
{
"type": "WEB",
"url": "https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20180711-phone-webui-inject"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/104731"
},
{
"type": "WEB",
"url": "http://www.securitytracker.com/id/1041285"
}
],
"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-G8WX-WWR2-J96M
Vulnerability from github – Published: 2022-05-17 04:41 – Updated: 2022-05-17 04:41The uploadFile function in upload/index.php in CosCMS before 1.822 allows remote administrators to execute arbitrary commands via shell metacharacters in the name of an uploaded file.
{
"affected": [],
"aliases": [
"CVE-2013-1668"
],
"database_specific": {
"cwe_ids": [
"CWE-78"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2014-05-23T14:55:00Z",
"severity": "HIGH"
},
"details": "The uploadFile function in upload/index.php in CosCMS before 1.822 allows remote administrators to execute arbitrary commands via shell metacharacters in the name of an uploaded file.",
"id": "GHSA-g8wx-wwr2-j96m",
"modified": "2022-05-17T04:41:03Z",
"published": "2022-05-17T04:41:03Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2013-1668"
},
{
"type": "WEB",
"url": "https://github.com/diversen/gallery/commit/7d58f870e8edc6597485dd1b80ea9fb78580190c"
},
{
"type": "WEB",
"url": "https://www.htbridge.com/advisory/HTB23145"
},
{
"type": "WEB",
"url": "http://archives.neohapsis.com/archives/bugtraq/2013-03/0033.html"
},
{
"type": "WEB",
"url": "http://osvdb.org/90927"
},
{
"type": "WEB",
"url": "http://www.coscms.org/blog/view/4/Version-1.822"
},
{
"type": "WEB",
"url": "http://www.exploit-db.com/exploits/24629"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/58332"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-G93H-9P7R-VHFM
Vulnerability from github – Published: 2025-08-27 18:31 – Updated: 2025-08-27 18:31A vulnerability in the CLI of Cisco UCS Manager Software could allow an authenticated, local attacker with administrative privileges to read or create a file or overwrite any file on the file system of the underlying operating system of an affected device, including system files. This vulnerability is due to insufficient input validation of command arguments supplied by the user. An attacker could exploit this vulnerability by authenticating to a device and submitting crafted input to the affected command. A successful exploit could allow the attacker to read or create a file or overwrite any file on the file system of the underlying operating system of the affected device, including system files. To exploit this vulnerability, the attacker must have valid administrative credentials on the affected device.
{
"affected": [],
"aliases": [
"CVE-2025-20295"
],
"database_specific": {
"cwe_ids": [
"CWE-78"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-08-27T17:15:35Z",
"severity": "MODERATE"
},
"details": "A vulnerability in the CLI of Cisco UCS Manager Software could allow an authenticated, local attacker with administrative privileges to read or create a file or overwrite any file on the file system of the underlying operating system of an affected device, including system files.\n\u0026nbsp;\nThis vulnerability is due to insufficient input validation of command arguments supplied by the user. An attacker could exploit this vulnerability by authenticating to a device and submitting crafted input to the affected command. A successful exploit could allow the attacker to read or create a file or overwrite any file on the file system of the underlying operating system of the affected device, including system files. To exploit this vulnerability, the attacker must have valid administrative credentials on the affected device.",
"id": "GHSA-g93h-9p7r-vhfm",
"modified": "2025-08-27T18:31:54Z",
"published": "2025-08-27T18:31:54Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-20295"
},
{
"type": "WEB",
"url": "https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ucs-multi-cmdinj-E4Ukjyrz"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N",
"type": "CVSS_V3"
}
]
}
GHSA-G94V-8MRM-P53C
Vulnerability from github – Published: 2022-05-17 04:40 – Updated: 2022-05-17 04:40Autodesk VRED Professional 2014 before SR1 SP8 allows remote attackers to execute arbitrary code via Python os library calls in Python API commands to the integrated web server.
{
"affected": [],
"aliases": [
"CVE-2014-2967"
],
"database_specific": {
"cwe_ids": [
"CWE-78"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2014-07-07T11:01:00Z",
"severity": "HIGH"
},
"details": "Autodesk VRED Professional 2014 before SR1 SP8 allows remote attackers to execute arbitrary code via Python os library calls in Python API commands to the integrated web server.",
"id": "GHSA-g94v-8mrm-p53c",
"modified": "2022-05-17T04:40:41Z",
"published": "2022-05-17T04:40:41Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2014-2967"
},
{
"type": "WEB",
"url": "http://www.kb.cert.org/vuls/id/402020"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-G953-3VV7-4PC3
Vulnerability from github – Published: 2025-10-07 18:31 – Updated: 2025-10-07 18:31Dell PowerProtect Data Domain with Data Domain Operating System (DD OS) of Feature Release versions 7.7.1.0 through 8.3.0.15, LTS2025 release version 8.3.1.0, LTS2024 release versions 7.13.1.0 through 7.13.1.30, LTS 2023 release versions 7.10.1.0 through 7.10.1.60, contain an Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') vulnerability. A high privileged attacker with local access could potentially exploit this vulnerability, leading to arbitrary command execution. Exploitation may allow privilege escalation to root.
{
"affected": [],
"aliases": [
"CVE-2025-43906"
],
"database_specific": {
"cwe_ids": [
"CWE-78"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-10-07T18:15:59Z",
"severity": "MODERATE"
},
"details": "Dell PowerProtect Data Domain with Data Domain Operating System (DD OS) of Feature Release versions 7.7.1.0 through 8.3.0.15, LTS2025 release version 8.3.1.0, LTS2024 release versions 7.13.1.0 through 7.13.1.30, LTS 2023 release versions 7.10.1.0 through 7.10.1.60, contain an Improper Neutralization of Special Elements used in an OS Command (\u0027OS Command Injection\u0027) vulnerability. A high privileged attacker with local access could potentially exploit this vulnerability, leading to arbitrary command execution. Exploitation may allow privilege escalation to root.",
"id": "GHSA-g953-3vv7-4pc3",
"modified": "2025-10-07T18:31:11Z",
"published": "2025-10-07T18:31:11Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-43906"
},
{
"type": "WEB",
"url": "https://www.dell.com/support/kbdoc/en-us/000376224/dsa-2025-333-security-update-for-dell-powerprotect-data-domain-multiple-vulnerabilities"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-G954-8257-GR6C
Vulnerability from github – Published: 2023-05-23 03:30 – Updated: 2024-04-04 04:18OS command injection vulnerability in the mail setting page of SolarView Compact SV-CPT-MC310 versions prior to Ver.8.10 and SV-CPT-MC310F versions prior to Ver.8.10 allows remote authenticated attackers to execute an arbitrary OS command.
{
"affected": [],
"aliases": [
"CVE-2023-27521"
],
"database_specific": {
"cwe_ids": [
"CWE-78"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-05-23T02:15:09Z",
"severity": "HIGH"
},
"details": "OS command injection vulnerability in the mail setting page of SolarView Compact SV-CPT-MC310 versions prior to Ver.8.10 and SV-CPT-MC310F versions prior to Ver.8.10 allows remote authenticated attackers to execute an arbitrary OS command.",
"id": "GHSA-g954-8257-gr6c",
"modified": "2024-04-04T04:18:15Z",
"published": "2023-05-23T03:30:16Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-27521"
},
{
"type": "WEB",
"url": "https://jvn.jp/en/vu/JVNVU92106300"
},
{
"type": "WEB",
"url": "https://www.contec.com/jp/api/downloadlogger?download=/-/media/Contec/jp/support/security-info/contec_security_solarview_230508.pdf"
},
{
"type": "WEB",
"url": "https://www.contec.com/jp/download/donwload-list/?itemid=b28c8b7c-9f40-40b2-843c-b5b04c035b0e#firmware"
}
],
"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"
}
]
}
GHSA-G95V-666P-2M3X
Vulnerability from github – Published: 2023-10-16 12:33 – Updated: 2024-04-04 08:40An OS command injection vulnerability exists in the httpd iperfrun.cgi functionality of FreshTomato 2023.3. A specially crafted HTTP request can lead to arbitrary command execution. An attacker can send an HTTP request to trigger this vulnerability.
{
"affected": [],
"aliases": [
"CVE-2023-3991"
],
"database_specific": {
"cwe_ids": [
"CWE-78"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2023-10-16T10:15:11Z",
"severity": "CRITICAL"
},
"details": "An OS command injection vulnerability exists in the httpd iperfrun.cgi functionality of FreshTomato 2023.3. A specially crafted HTTP request can lead to arbitrary command execution. An attacker can send an HTTP request to trigger this vulnerability.",
"id": "GHSA-g95v-666p-2m3x",
"modified": "2024-04-04T08:40:17Z",
"published": "2023-10-16T12:33:36Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-3991"
},
{
"type": "WEB",
"url": "https://govtech-csg.github.io/security-advisories/2023/10/16/CVE-2023-3991.html"
}
],
"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"
}
]
}
Mitigation
If at all possible, use library calls rather than external processes to recreate the desired functionality.
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
Strategy: Attack Surface Reduction
For any data that will be used to generate a command to be executed, keep as much of that data out of external control as possible. For example, in web applications, this may require storing the data locally in the session's state instead of sending it out to the client in a hidden form field.
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-4.3
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.
- For example, consider using the ESAPI Encoding control [REF-45] or a similar tool, library, or framework. These will help the programmer encode outputs in a manner less prone to error.
Mitigation MIT-28
Strategy: Output Encoding
While it is risky to use dynamically-generated query strings, code, or commands that mix control and data together, sometimes it may be unavoidable. Properly quote arguments and escape any special characters within those arguments. The most conservative approach is to escape or filter all characters that do not pass an extremely strict allowlist (such as everything that is not alphanumeric or white space). If some special characters are still needed, such as white space, wrap each argument in quotes after the escaping/filtering step. Be careful of argument injection (CWE-88).
Mitigation
If the program to be executed allows arguments to be specified within an input file or from standard input, then consider using that mode to pass arguments instead of the command line.
Mitigation MIT-27
Strategy: Parameterization
- If available, use structured mechanisms that automatically enforce the separation between data and code. These mechanisms may be able to provide the relevant quoting, encoding, and validation automatically, instead of relying on the developer to provide this capability at every point where output is generated.
- Some languages offer multiple functions that can be used to invoke commands. Where possible, identify any function that invokes a command shell using a single string, and replace it with a function that requires individual arguments. These functions typically perform appropriate quoting and filtering of arguments. For example, in C, the system() function accepts a string that contains the entire command to be executed, whereas execl(), execve(), and others require an array of strings, one for each argument. In Windows, CreateProcess() only accepts one command at a time. In Perl, if system() is provided with an array of arguments, then it will quote each of the arguments.
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.
- When constructing OS command strings, use stringent allowlists that limit the character set based on the expected value of the parameter in the request. This will indirectly limit the scope of an attack, but this technique is less important than proper output encoding and escaping.
- Note that proper output encoding, escaping, and quoting is the most effective solution for preventing OS command injection, although input validation may provide some defense-in-depth. This is because it effectively limits what will appear in output. Input validation will not always prevent OS command injection, especially if you are required to support free-form text fields that could contain arbitrary characters. For example, when invoking a mail program, you might need to allow the subject field to contain otherwise-dangerous inputs like ";" and ">" characters, which would need to be escaped or otherwise handled. In this case, stripping the character might reduce the risk of OS command injection, but it would produce incorrect behavior because the subject field would not be recorded as the user intended. This might seem to be a minor inconvenience, but it could be more important when the program relies on well-structured subject lines in order to pass messages to other components.
- Even if you make a mistake in your validation (such as forgetting one out of 100 input fields), appropriate encoding is still likely to protect you from injection-based attacks. As long as it is not done in isolation, input validation is still a useful technique, since it may significantly reduce your attack surface, allow you to detect some attacks, and provide other security benefits that proper encoding does not address.
Mitigation MIT-21
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.
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 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 OS Command Injection, error information passed back to the user might reveal whether an OS command is being executed and possibly which command is being used.
Mitigation
Strategy: Sandbox or Jail
Use runtime policy enforcement to create an allowlist of allowable commands, then prevent use of any command that does not appear in the allowlist. Technologies such as AppArmor are available to do this.
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-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-108: Command Line Execution through SQL Injection
An attacker uses standard SQL injection methods to inject data into the command line for execution. This could be done directly through misuse of directives such as MSSQL_xp_cmdshell or indirectly through injection of data into the database that would be interpreted as shell commands. Sometime later, an unscrupulous backend application (or could be part of the functionality of the same application) fetches the injected data stored in the database and uses this data as command line arguments without performing proper validation. The malicious data escapes that data plane by spawning new commands to be executed on the host.
CAPEC-15: Command Delimiters
An attack of this type exploits a programs' vulnerabilities that allows an attacker's commands to be concatenated onto a legitimate command with the intent of targeting other resources such as the file system or database. The system that uses a filter or denylist input validation, as opposed to allowlist validation is vulnerable to an attacker who predicts delimiters (or combinations of delimiters) not present in the filter or denylist. As with other injection attacks, the attacker uses the command delimiter payload as an entry point to tunnel through the application and activate additional attacks through SQL queries, shell commands, network scanning, and so on.
CAPEC-43: Exploiting Multiple Input Interpretation Layers
An attacker supplies the target software with input data that contains sequences of special characters designed to bypass input validation logic. This exploit relies on the target making multiples passes over the input data and processing a "layer" of special characters with each pass. In this manner, the attacker can disguise input that would otherwise be rejected as invalid by concealing it with layers of special/escape characters that are stripped off by subsequent processing steps. The goal is to first discover cases where the input validation layer executes before one or more parsing layers. That is, user input may go through the following logic in an application: <parser1> --> <input validator> --> <parser2>. In such cases, the attacker will need to provide input that will pass through the input validator, but after passing through parser2, will be converted into something that the input validator was supposed to stop.
CAPEC-6: Argument Injection
An attacker changes the behavior or state of a targeted application through injecting data or command syntax through the targets use of non-validated and non-filtered arguments of exposed services or methods.
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.