CVE-2021-24853

QR Redirector <= 1.5 - Cross-Site Request Forgery

2021-10-18 00:00

Strategic Overview

Status: Patched in 1.6
Affected Plugin: QR Redirector
Affected Version: < 1.6
CVSS: 4.3Medium
Weakness type: CWE-352 · Cross-Site Request Forgery (CSRF)
CVE: CVE-2021-24853

At a glance

CVE-2021-24853 is a medium-severity Cross-Site Request Forgery (CSRF) vulnerability in the QR Redirector WordPress plugin, affecting versions < 1.6. It carries a CVSS score of 4.3 (reachable over the network; low attack complexity). Exploitation requires no authentication. The issue is fixed in version 1.6; sites on affected versions should update now. Disclosed October 2021, reported by apple502j.

Vulnerability Overview

The QR Redirector WordPress plugin before 1.6 does not have capability and CSRF checks when saving bulk QR Redirector settings via the qr_save_bulk AJAX action, which could allow any authenticated user, such as subscriber to change the redirect response status code of arbitrary QR Redirects

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-352: Cross-Site Request Forgery (CSRF)

Reaching this weakness in QR Redirector < 1.6 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 QR Redirector the fix is 1.6: builds < 1.6 are affected, anything from 1.6 onward is not.

Remediation

Update to version 1.6, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to QR Redirector: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: QR Redirector 1.6 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-24853 https://www.wordfence.com/threat-intel/vulnerabilities/id/82f311a5-6ef3-4052-ab9d-fdb23f7b7406 https://nvd.nist.gov/vuln/detail/CVE-2021-24853

Related records

Other vulnerabilities in QR Redirector

CVSS Vector

4.3

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeUnchanged
ConfidentialityNone
IntegrityLow
AvailabilityNone

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