CVE-2021-24670

CoolClock <= 4.3.4 - Authenticated Stored Cross-Site Scripting

2021-08-30 00:00

Strategic Overview

Status: Patched in 4.3.5
Affected Plugin: CoolClock
Affected Version: < 4.3.5
CVSS: 5.4Medium
Weakness type: CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CVE: CVE-2021-24670

At a glance

CVE-2021-24670 is a medium-severity Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in the CoolClock WordPress plugin, affecting versions < 4.3.5. It carries a CVSS score of 5.4 (reachable over the network; low attack complexity). Exploitation requires an authenticated account. The issue is fixed in version 4.3.5; sites on affected versions should update now. Disclosed August 2021, reported by apple502j.

Vulnerability Overview

The CoolClock WordPress plugin before 4.3.5 does not escape some shortcode attributes, allowing users with a role as low as Contributor toperform Stored Cross-Site Scripting attacks

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 CoolClock < 4.3.5 takes any authenticated account. 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 CoolClock the fix is 4.3.5: builds < 4.3.5 are affected, anything from 4.3.5 onward is not.

Remediation

Update to version 4.3.5, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to CoolClock: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: CoolClock 4.3.5 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-24670 https://www.wordfence.com/threat-intel/vulnerabilities/id/5bb45de4-2c83-4c77-aec0-f28ade966468 https://nvd.nist.gov/vuln/detail/CVE-2021-24670

CVSS Vector

5.4

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

Base

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

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