CVE-2015-9503

Modern <= 1.4.1 - Cross-Site Scripting

2015-05-12 00:00

Strategic Overview

Status: Patched in 1.4.2
Affected Theme: Modern
Affected Version: <= 1.4.1
CVSS: 6.1Medium
Weakness type: CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE: CVE-2015-9503

At a glance

CVE-2015-9503 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the Modern WordPress theme, affecting versions <= 1.4.1. 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 1.4.2; sites on affected versions should update now. Disclosed May 2015.

Vulnerability Overview

The Modern theme before 1.4.2 for WordPress has XSS via the genericons/example.html anchor identifier.

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 Modern <= 1.4.1 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 Modern the fix is 1.4.2: builds <= 1.4.1 are affected, anything from 1.4.2 onward is not.

Remediation

Update to version 1.4.2, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Modern: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Modern 1.4.2 closes this, and updating the theme is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2015-9503 https://www.wordfence.com/threat-intel/vulnerabilities/id/ae1820ab-6a24-45b3-801c-34c5515c8868 https://nvd.nist.gov/vuln/detail/CVE-2015-9503

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

This record contains material that is subject to copyright

CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE®). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy.

https://www.cve.org/Legal/TermsOfUse

Defiant hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute this software vulnerability information. Any copy of the software vulnerability information you make for such purposes is authorized provided that you include a hyperlink to this vulnerability record and reproduce Defiant's copyright designation and this license in any such copy.

https://www.wordfence.com/wordfence-intelligence-terms-and-conditions/