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Null characters not escaped

High
ericcornelissen published GHSA-f2rp-38vg-j3gh Mar 13, 2021

Package

npm shescape (npm)

Affected versions

< 1.1.3

Patched versions

1.1.3

Description

Impact

Anyone using Shescape to defend against shell injection may still be vulnerable against shell injection if the attacker manages to insert a null character into the payload. For example (on Windows):

const cp = require("child_process");
const shescape = require("shescape");

const nullChar = String.fromCharCode(0);
const payload = "foo\" && ls -al ${nullChar} && echo \"bar";
console.log(cp.execSync(`echo ${shescape.quote(payload)}`));
// foototal 3
// drwxr-xr-x 1 owner XXXXXX      0 Mar 13 18:44 .
// drwxr-xr-x 1 owner XXXXXX      0 Mar 13 00:09 ..
// drwxr-xr-x 1 owner XXXXXX      0 Mar 13 18:42 folder                                                                 
// -rw-r--r-- 1 owner XXXXXX      0 Mar 13 18:42 file

Patches

The problem has been patched in v1.1.3 which you can upgrade to now. No further changes are required.

Workarounds

Alternatively, null characters can be stripped out manually using e.g. arg.replace(/\u{0}/gu, "")

Severity

High

CVE ID

CVE-2021-21384

Weaknesses

No CWEs