CVE-2016-6897

WordPress Core < 4.6 - Cross-Site Request Forgery

2016-08-16 00:00

Strategic Overview

Status: Patched in 4.6
Affected Core: WordPress 4.6
Affected Version: < 4.6
CVSS: 8.8High
Weakness type: CWE-352 · Cross-Site Request Forgery (CSRF)
CVE: CVE-2016-6897

At a glance

CVE-2016-6897 is a high-severity Cross-Site Request Forgery (CSRF) vulnerability in the WordPress 4.6 WordPress release line, affecting < 4.6. It carries a CVSS score of 8.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 4.6; sites on affected versions should update now. Disclosed August 2016.

Vulnerability Overview

Cross-site request forgery (CSRF) vulnerability in the wp_ajax_update_plugin function in wp-admin/includes/ajax-actions.php in WordPress before 4.6 allows remote attackers to hijack the authentication of subscribers for /dev/random read operations by leveraging a late call to the check_ajax_referer function, a related issue to CVE-2016-6896.

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. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-352: Cross-Site Request Forgery (CSRF)

Reaching this weakness in WordPress 4.6 < 4.6 takes a caller who can reach the endpoint. Cross-site request forgery abuses the fact that browsers attach a victim's cookies to any request, so a state-changing action that only checks who you are, not whether you meant to act, can be triggered from another site.

An attacker who gets a logged-in user to load a crafted page can perform that action as them, with the impact scaling to whatever the victim's role is allowed to do. For WordPress 4.6 the fix is 4.6: builds < 4.6 are affected, anything from 4.6 onward is not.

Remediation

Update to version 4.6, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to WordPress 4.6: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: updating to 4.6 is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2016-6897 https://www.wordfence.com/threat-intel/vulnerabilities/id/d6dfed14-bb6f-4418-bdd8-9c548e63dac0 https://nvd.nist.gov/vuln/detail/CVE-2016-6897

Related records

Same weakness class

Other vulnerabilities in WordPress 4.6

CVSS Vector

8.8

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

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