CVE-2020-5650

Simple Download Monitor <= 3.8.8 - Unauthenticated Stored Cross-Site Scripting

2020-10-21 00:00
Gen Sato

Strategic Overview

Status
Patched in 3.3.9
Affected Plugin
Simple Download Monitor
Affected Version
<= 3.3.8
CVSS
6.1Medium
Weakness type
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE
CVE-2020-5650
View all Simple Download Monitor vulnerabilities

At a glance

CVE-2020-5650 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Simple Download Monitor WordPress plugin, affecting versions <= 3.3.8. 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 3.3.9; sites on affected versions should update now. Disclosed October 2020, reported by Gen Sato.

Vulnerability Overview

The Simple Download Monitor plugin for WordPress is vulnerable to Cross-Site Scripting in versions up to, and including, 3.8.8 due to insufficient input sanitization and output escaping on the User-Agent header. This makes it possible for attackers to inject arbitrary web scripts that execute in a victim's browser.

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')

Reaching this weakness in Simple Download Monitor <= 3.3.8 takes no account at all. 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 Simple Download Monitor the fix is 3.3.9: builds <= 3.3.8 are affected, anything from 3.3.9 onward is not.

Remediation

Update to version 3.3.9, or a newer patched version

How does WordSec protect against this?

Requests carrying this pattern arrive without a session, so nothing upstream of the firewall gets a chance to reject them: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Simple Download Monitor 3.3.9 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Login Security
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2020-5650https://www.wordfence.com/threat-intel/vulnerabilities/id/32f03892-500f-4925-9b3d-3160243de8a0https://nvd.nist.gov/vuln/detail/CVE-2020-5650

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C