CVE-2023-33999

Freemius SDK <= 2.5.9 - Reflected Cross-Site Scripting via fs_request_get

2023-07-18 00:00

Strategic Overview

Status: Patched in 2.8.0
Affected Plugin: MasterStudy LMS WordPress Plugin – for Online Courses and Education
Affected Version: <= 2.7.9
CVSS: 6.1Medium
Weakness type: CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE: CVE-2023-33999

View all MasterStudy LMS WordPress Plugin – for Online Courses and Education vulnerabilities

At a glance

CVE-2023-33999 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the MasterStudy LMS WordPress Plugin WordPress plugin, affecting versions <= 2.7.9. It carries a CVSS score of 6.1 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 2.8.0; sites on affected versions should update now. Disclosed July 2023, reported by Rafie Muhammad.

Vulnerability Overview

The Freemius SDK for WordPress is vulnerable to Reflected Cross-Site Scripting via the ‘fs_request_get’ function in versions up to, and including, 2.5.9 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no privileges on the target site.

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

MasterStudy LMS WordPress Plugin <= 2.7.9 carries this weakness at fs_request_get, and reaching it takes a caller who can reach the endpoint. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.

Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For MasterStudy LMS WordPress Plugin the fix is 2.8.0: builds <= 2.7.9 are affected, anything from 2.8.0 onward is not.

Remediation

Update to version 2.8.0, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to MasterStudy LMS WordPress Plugin: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: MasterStudy LMS WordPress Plugin 2.8.0 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2023-33999 https://www.wordfence.com/threat-intel/vulnerabilities/id/5253fe2b-040b-417c-b257-0cb59ee5aa6e https://nvd.nist.gov/vuln/detail/CVE-2023-33999

Related records

Same weakness class

Other vulnerabilities in MasterStudy LMS WordPress Plugin – for Online Courses and Education

CVSS Vector

6.1

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeChanged
ConfidentialityLow
IntegrityLow
AvailabilityNone

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