CVE-2017-5491

WordPress Core < 4.7.1 - Authorization Bypass

2017-01-11 00:00

Strategic Overview

Status: Patched in 3.7.17
Affected Core: WordPress 4.7
Affected Version: 3.7 – 4.7.0 · 12 branches
CVSS: 8.3High
Weakness type: CWE-285 · Improper Authorization
CVE: CVE-2017-5491

At a glance

CVE-2017-5491 is a high-severity Improper Authorization vulnerability in the WordPress 4.7 WordPress release line, affecting 3.7 – 4.7.0 · 12 branches. It carries a CVSS score of 8.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 3.7.17; sites on affected versions should update now. Disclosed January 2017, reported by John Blackbourn.

Vulnerability Overview

wp-mail.php in WordPress before 4.7.1 might allow remote attackers to bypass intended posting restrictions via a spoofed mail server with the mail.example.com name.

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, and no interaction from a victim user.

CWE-285: Improper Authorization

Reaching this weakness in WordPress 4.7 3.7 – 4.7.0 · 12 branches takes a caller who can reach the endpoint. Improper authorization means a permission check exists but does not cover the case being exercised, so a caller who is allowed to do one thing is allowed to do a neighbouring thing as well.

A lower-privileged account performs an action reserved for a higher one, which on a multi-author or membership site means an ordinary user reaching administrative behaviour. For WordPress 4.7 the fix is 3.7.17: builds 3.7 – 4.7.0 · 12 branches are affected, anything from 3.7.17 onward is not.

Remediation

Update to one of the following versions, or a newer patched version: 3.7.17, 3.8.17, 3.9.15, 4.0.14, 4.1.14, 4.2.11, 4.3.7, 4.4.6, 4.5.5, 4.6.2, 4.7.1

How does WordSec protect against this?

Because it turns on account access, WordSec's login security is the relevant layer: role-based two-factor, captcha and brute-force limits raise the cost of getting the account this needs. None of that substitutes for the fix: updating to 3.7.17 is the step that ends it.

Login Security
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2017-5491 https://www.wordfence.com/threat-intel/vulnerabilities/id/fd4ac2b0-120a-4e68-bf8d-e039336fe9dc https://nvd.nist.gov/vuln/detail/CVE-2017-5491

Related records

Same weakness class

Other vulnerabilities in WordPress 4.7

CVSS Vector

8.3

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeChanged
ConfidentialityLow
IntegrityLow
AvailabilityLow

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