CVE-2018-20434: Librenms/librenms LibreNMS Arbitrary OS Commands Execution Vulnerability

CRITICAL
Advisory Identifier: GHSA-62q7-qj6g-gvr7
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CVSS 9.8
CWE-78
Published
Advisory Summary

CVE-2018-20434 is a CRITICAL (CVSS 9.8) librenms arbitrary os commands execution vulnerability (CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')) affecting Librenms/librenms libraries in the Packagist ecosystem. The issue involves librenms arbitrary os commands execution. Remediation is available in the latest vendor maintenance releases.

CVE-2018-20434 at a Glance

CVE Identifier CVE-2018-20434
GHSA Identifier GHSA-62q7-qj6g-gvr7
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Affected Product Librenms/librenms
Package Ecosystem Packagist
Published Date
Last Updated

Security Impact

CVSS: 9.8

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2018-20434

To remediate this vulnerability, upgrade all affected Librenms/librenms dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

librenms/librenms fixed: Latest secure release 
Upgrade librenms/librenms to Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for librenms/librenms

How to Check if You Are Affected

To determine whether your application is affected by CVE-2018-20434, inspect your project dependencies for Librenms/librenms:

inspect dependencies for librenms/librenms

Analyze the terminal output to locate any version of Librenms/librenms in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection'), where 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. In Librenms/librenms, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

LibreNMS 1.46 allows remote attackers to execute arbitrary OS commands by using the `$_POST['community']` parameter to `html/pages/addhost.inc.php` during creation of a new device, and then making a `/ajax_output.php?id=capture&format=text&type=snmpwalk&hostname=localhost request that triggers html/includes/output/capture.inc.php` command mishandling.

CVE-2018-20434 Affected Librenms/librenms Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
librenms/librenms
 Packagist
1.46
All 1 versions
1.46
None specified

References

NVD — CVE-2018-20434 NVD
https://nvd.nist.gov/vuln/detail/CVE-2018-20434
drive.google.com/file/d/1lcgmoy8x-tg... WEB
https://drive.google.com/file/d/1LcGmOY8x-TG-wnNr-cM_f854kxk0etva/view?usp=sharing
Librenms/librenms Source Repository REPOSITORY
https://gist.github.com/mhaskar/516df57aafd8c6e3a1d70765075d372d
Librenms/librenms Source Repository REPOSITORY
https://github.com/librenms/librenms
shells.systems/librenms-v1-46-remo... WEB
https://shells.systems/librenms-v1-46-remote-code-execution-cve-2018-20434

Frequently Asked Questions

What is CVE-2018-20434?
CVE-2018-20434 is a security vulnerability in Librenms/librenms involving LibreNMS arbitrary OS commands execution under CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection').
Which Librenms/librenms versions are affected?
Affected versions include releases prior to current release patches across affected packages: librenms/librenms.
What version fixes CVE-2018-20434?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is librenms/librenms affected?
Yes, librenms/librenms is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2018-20434?
CVE-2018-20434 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2018-20434?
CVE-2018-20434 is classified under CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') (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.).
How can I check Packagist dependencies for CVE-2018-20434?
Run the dependency tree command: 'inspect dependencies for librenms/librenms'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-62q7-qj6g-gvr7",
  "modified" : "2024-04-24T22:10:15Z",
  "published" : "2022-05-24T16:44:30Z",
  "aliases" : [ "CVE-2018-20434" ],
  "summary" : "LibreNMS arbitrary OS commands execution",
  "details" : "LibreNMS 1.46 allows remote attackers to execute arbitrary OS commands by using the `$_POST['community']` parameter to `html/pages/addhost.inc.php` during creation of a new device, and then making a `/ajax_output.php?id=capture&format=text&type=snmpwalk&hostname=localhost request that triggers html/includes/output/capture.inc.php` command mishandling.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "librenms/librenms"
    },
    "versions" : [ "1.46" ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2018-20434"
  }, {
    "type" : "WEB",
    "url" : "https://drive.google.com/file/d/1LcGmOY8x-TG-wnNr-cM_f854kxk0etva/view?usp=sharing"
  }, {
    "type" : "WEB",
    "url" : "https://gist.github.com/mhaskar/516df57aafd8c6e3a1d70765075d372d"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/librenms/librenms"
  }, {
    "type" : "WEB",
    "url" : "https://shells.systems/librenms-v1-46-remote-code-execution-cve-2018-20434"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-78" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-04-24T22:10:15Z",
    "nvd_published_at" : "2019-04-24T21:29:00Z"
  }
}