CVE-2021-25033

WordPress Newsletter Plugin – Noptin < 1.6.5 - Open Redirect

2022-01-17 00:00

Strategic Overview

Status: Patched in 1.6.5
Affected Plugin: Simple Newsletter Plugin – Noptin
Affected Version: < 1.6.5
CVSS: 6.1Medium
Weakness type: CWE-601 · URL Redirection to Untrusted Site ('Open Redirect')
CVE: CVE-2021-25033

View all Simple Newsletter Plugin – Noptin vulnerabilities

At a glance

CVE-2021-25033 is a medium-severity URL Redirection to Untrusted Site ('Open Redirect') vulnerability in the Simple Newsletter Plugin WordPress plugin, affecting versions < 1.6.5. 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 1.6.5; sites on affected versions should update now. Disclosed January 2022, reported by Trang LKB.

Vulnerability Overview

The WordPress Newsletter Plugin WordPress plugin before 1.6.5 does not validate the to parameter before redirecting the user to its given value, leading to an open redirect issue.

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-601: URL Redirection to Untrusted Site ('Open Redirect')

Reaching this weakness in Simple Newsletter Plugin < 1.6.5 takes a caller who can reach the endpoint. An open redirect is a page that takes a destination from the request and sends the browser there without checking that the destination belongs to the site.

A link that starts on a trusted domain finishes on an attacker's, which is what makes phishing and consent-screen abuse credible to the person clicking it. For Simple Newsletter Plugin the fix is 1.6.5: builds < 1.6.5 are affected, anything from 1.6.5 onward is not.

Remediation

Update to version 1.6.5, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Simple Newsletter Plugin: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Simple Newsletter Plugin 1.6.5 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-25033 https://www.wordfence.com/threat-intel/vulnerabilities/id/c5372890-72d4-482d-a7f2-04a50520c4dc https://nvd.nist.gov/vuln/detail/CVE-2021-25033

Related records

Other vulnerabilities in Simple Newsletter Plugin – Noptin

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/