CVE-2021-24423

UpdraftPlus WordPress Backup Plugin < 1.6.59 - Stored Cross-Site Scripting

2021-05-09 00:00

Strategic Overview

Status: Patched in 1.6.59
Affected Plugin: UpdraftPlus: WP Backup & Migration Plugin
Affected Version: < 1.6.59
CVSS: 4.8Medium
Weakness type: CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE: CVE-2021-24423

View all UpdraftPlus: WP Backup & Migration Plugin vulnerabilities

At a glance

CVE-2021-24423 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the UpdraftPlus WordPress plugin, affecting versions < 1.6.59. It carries a CVSS score of 4.8 (reachable over the network; low attack complexity). The issue is fixed in version 1.6.59; sites on affected versions should update now. Disclosed May 2021, reported by R3N0.

Vulnerability Overview

The UpdraftPlus WordPress Backup Plugin WordPress plugin before 1.6.59 does not sanitise its updraft_service settings, allowing high privilege users to set malicious JavaScript payload in it and leading to a Stored Cross-Site Scripting 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.

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Reaching this weakness in UpdraftPlus < 1.6.59 takes a caller who can reach the endpoint. Cross-site scripting happens when input from a request is written into a page without being escaped for the context it lands in, so the browser parses attacker-supplied text as markup or script.

Injected script runs with the privileges of whoever views the affected page, which is how these flaws turn into administrator session theft, silent account creation or persistent backdoors in page content. For UpdraftPlus the fix is 1.6.59: builds < 1.6.59 are affected, anything from 1.6.59 onward is not.

Remediation

Update to version 1.6.59, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to UpdraftPlus: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: UpdraftPlus 1.6.59 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-24423 https://www.wordfence.com/threat-intel/vulnerabilities/id/0987f9a5-eb11-4756-a09a-26dc66a8c690 https://nvd.nist.gov/vuln/detail/CVE-2021-24423

Related records

Same weakness class

Other vulnerabilities in UpdraftPlus: WP Backup & Migration Plugin

CVSS Vector

4.8

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredHigh
User InteractionRequired
ScopeChanged
ConfidentialityLow
IntegrityLow
AvailabilityNone

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