CVE-2019-7412

PS PHPCaptcha <= 1.1.0 - Authenticated Denial of Service

2019-02-16 00:00

Strategic Overview

Status: Patched in 1.2.0
Affected Plugin: PS PHPCaptcha WP
Affected Version: <= 1.1.0
CVSS: 6.5Medium
Weakness type: CWE-20 · Improper Input Validation
CVE: CVE-2019-7412

View all PS PHPCaptcha WP vulnerabilities

At a glance

CVE-2019-7412 is a medium-severity Improper Input Validation vulnerability in the PS PHPCaptcha WP WordPress plugin, affecting versions <= 1.1.0. It carries a CVSS score of 6.5 (reachable over the network; low attack complexity; high availability impact). Exploitation requires an authenticated account. The issue is fixed in version 1.2.0; sites on affected versions should update now. Disclosed February 2019, reported by Metamorfosec.

Vulnerability Overview

The PS PHPCaptcha pluginfor WordPress is vulnerable to Denial of Service in versions up to, and including, 1.1.0. This is due to improper sanitization of user inputted values. This makes it possible for authenticated attackers to slow and or completely freeze the vulnerable service.

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 interaction from a victim user. A successful exploit has high impact on availability.

CWE-20: Improper Input Validation

Reaching this weakness in PS PHPCaptcha WP <= 1.1.0 takes any authenticated account. Improper input validation means the application accepts input without confirming it has the form, type or range the code downstream assumes.

The concrete impact depends on where the unvalidated value lands, which is why records in this class range from cosmetic bugs to full compromise. For PS PHPCaptcha WP the fix is 1.2.0: builds <= 1.1.0 are affected, anything from 1.2.0 onward is not.

Remediation

Update to version 1.2.0, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to PS PHPCaptcha WP: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: PS PHPCaptcha WP 1.2.0 closes this, and updating the plugin is the step that ends it.

Firewall
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2019-7412 https://www.wordfence.com/threat-intel/vulnerabilities/id/b9ed7e26-34f0-4e5d-b560-03b1de9c5c95 https://nvd.nist.gov/vuln/detail/CVE-2019-7412

CVSS Vector

6.5

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredLow
User InteractionNone
ScopeUnchanged
ConfidentialityNone
IntegrityNone
AvailabilityHigh

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