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GHSA-vm64-cfqx-3698

Code Injection in jsen

Source: GitHub Advisory Database (reviewed) High CVE-2020-7777

Packages

EcosystemPackageAffectedFixed in
npm jsen <= 0.6.6 no fix listed

Details

As written in the advisory (Markdown source, shown as plain text).

This affects all versions of package jsen. If an attacker can control the schema file, it could run arbitrary JavaScript code on the victim machine. In the module description and README file there is no mention about the risks of untrusted schema files, so it is assumed that this is applicable. In particular the required field of the schema is not properly sanitized. The resulting string that is build based on the schema definition is then passed to a `Function.apply();`, leading to an Arbitrary Code Execution. ### PoC ```js const jsen = require('jsen'); let schema = JSON.parse( { &quot;type&quot;: &quot;object&quot;, &quot;properties&quot;: { &quot;username&quot;: { &quot;type&quot;: &quot;string&quot; } }, &quot;required&quot;: [&quot;\\&quot;+process.mainModule.require(\&#39;child_process\&#39;).execSync(\&#39;touch malicious\&#39;)+\\&quot;&quot;] } ); const validate = jsen(schema); validate({}); ```

References

External links from the advisory. They lead to third-party sites.