CVE-2019-19133

CSS Hero <= 4.0.3 - Reflected Cross-Site Scripting

2019-12-02 00:00

Strategic Overview

Status: Patched in 4.07
Affected Plugin: CSS Hero
Affected Version: <= 4.03
CVSS: 6.1Medium
Weakness type: CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE: CVE-2019-19133

At a glance

CVE-2019-19133 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the CSS Hero WordPress plugin, affecting versions <= 4.03. 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 4.07; sites on affected versions should update now. Disclosed December 2019, reported by Cary Hooper.

Vulnerability Overview

The CSS Hero plugin through 4.0.3 for WordPress is prone to reflected XSS via the URI in a csshero_action=edit_page request because it fails to sufficiently sanitize user-supplied input. An attacker may leverage this issue to execute arbitrary JavaScript in the browser of an unsuspecting user in the context of the affected site. This may allow the attacker to steal cookies or launch other attacks.

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 CSS Hero <= 4.03 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 CSS Hero the fix is 4.07: builds <= 4.03 are affected, anything from 4.07 onward is not.

Remediation

Update to version 4.07, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to CSS Hero: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: CSS Hero 4.07 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2019-19133 https://www.wordfence.com/threat-intel/vulnerabilities/id/ffb97fa2-456c-4bc4-a09c-54daa17be3e8 https://nvd.nist.gov/vuln/detail/CVE-2019-19133

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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