CVE-2014-5266

WordPress Core < 3.9.2 - Denial of Service via XML #2

2014-08-06 00:00

Strategic Overview

Status: Patched in 3.7.4
Affected Core: WordPress 3.9
Affected Version: 3.7 – 3.9.1 · 4 branches
CVSS: 6.5Medium
Weakness type: CWE-400 · Uncontrolled Resource Consumption
CVE: CVE-2014-5266

At a glance

CVE-2014-5266 is a medium-severity Uncontrolled Resource Consumption vulnerability in the WordPress 3.9 WordPress release line, affecting 3.7 – 3.9.1 · 4 branches. It carries a CVSS score of 6.5 (reachable over the network; low attack complexity; high availability impact). The issue is fixed in version 3.7.4; sites on affected versions should update now. Disclosed August 2014, reported by Ivan Novikov.

Vulnerability Overview

The Incutio XML-RPC (IXR) Library, as used in WordPress before 3.9.2 and Drupal 6.x before 6.33 and 7.x before 7.31, does not limit the number of elements in an XML document, which allows remote attackers to cause a denial of service (CPU consumption) via a large document, a different vulnerability than CVE-2014-5265.

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 interaction from a victim user. A successful exploit has high impact on availability.

CWE-400: Uncontrolled Resource Consumption

Reaching this weakness in WordPress 3.9 3.7 – 3.9.1 · 4 branches takes a caller who can reach the endpoint. Uncontrolled resource consumption means a request can make the server do an amount of work it never bounds, because the size or repetition of the job is taken from the request rather than capped by the code.

A single caller can hold PHP workers, database connections or disk open long enough to slow the site for everyone, without needing any account or any other flaw. For WordPress 3.9 the fix is 3.7.4: builds 3.7 – 3.9.1 · 4 branches are affected, anything from 3.7.4 onward is not.

Remediation

Update to one of the following versions, or a newer patched version: 3.7.4, 3.8.4, 3.9.2

How does WordSec protect against this?

The attempt arrives as an ordinary request to WordPress 3.9: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: updating to 3.7.4 is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2014-5266 https://www.wordfence.com/threat-intel/vulnerabilities/id/b0382227-48eb-4a97-8f3c-5c8fc4bcc0b6 https://nvd.nist.gov/vuln/detail/CVE-2014-5266

Related records

Same weakness class

Other vulnerabilities in WordPress 3.9

CVSS Vector

6.5

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredLow
User InteractionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh

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