GHSA-cr3w-cw5w-h3fj: Saltcorn's Reflected XSS and Command Injection vulnerabilities can be chained for 1-click-RCE

Should you act?

• Only if you depend on one of the packages below, directly or transitively, in a vulnerable version. Check your lockfile with npm audit (or: npm ls <package>).
• No CVE has been assigned, so it will not appear in CVE-based scanners that ignore GitHub advisories. npm audit, pip-audit and Dependabot do read GitHub advisories.

Affected packages

Details

Summary 1. There is a reflected XSS vulnerability in the GET /admin/edit-codepage/:name route through the name parameter. This can be used to hijack the session of an admin if they click a specially crafted link. 2. Additionally, there is a Command Injection vulnerability in GET /admin/backup. The admin can inject a shell command in the backup password which is inserted in the command used to create the backup zip.

Both vulnerabilities can be chained to craft a malicious link which will execute an arbitrary shell command on the server if it is clicked by a saltcorn admin with an active session. I believe iframes could also be used to exploit this silently when the admin visits an attacker-controlled web page (though I have not tested that).

Details 1. The XSS vulnerability is here: https://github.com/saltcorn/saltcorn/blob/020893c0001678fd5ebd2c088ba68b395de1aabc/packages/server/routes/admin.js#L4886-L4887 Specifically, the name parameter is inserted into the pages breadcrumbs without sanitization. 2. The Command Injection happens here: https://github.com/saltcorn/saltcorn/blob/020893c0001678fd5ebd2c088ba68b395de1aabc/packages/saltcorn-admin-models/models/backup.ts#L381-L382

PoC 1. A minimal PoC for the XSS can be as simple as: http://localhost:3000/admin/edit-codepage/%3Cimg%20src%3Dx%20onerror%3Dalert%281%29%3E%0A (assuming saltcorn running at localhost:3000 and the user having an active admin session) 2. For the Command Injection, visit the backup section of saltcorn, set an admin password like ";$(whoami);" (including the quotation marks) and then click "Download a backup" in the "Manual backup" section. This should display an error page saying that /bin/sh could not find the binary named "root" or "saltcorn", depending on the user.

An example of an exploit that chains both vulnerabilities and generates the aforementioned malicious link: exploit.zip

Affected Versions Edit: The following Docker containers from docker hub were tested: 1.4.1, 1.4.0, 1.3.1, 1.3.0, 1.2.0, 1.1.2, 1.1.1, 1.0.0 The Command Injection is applicable to versions >= 1.3.0. The XSS is applicable to versions >= 1.1.1

CVSS: 9.6 (v3.1) CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Sources and references

1. GitHub Advisory GHSA-cr3w-cw5w-h3fj github.com
2. github.com github.com
3. github.com github.com
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5. github.com github.com

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