CVE-2020-36726

Ultimate Reviews < 2.1.33 - PHP Object Injection

2020-11-10 00:00

Strategic Overview

Status: Patched in 2.1.33
Affected Plugin: Ultimate Reviews
Affected Version: < 2.1.33
CVSS: 9.8Critical
Weakness type: CWE-502 · Deserialization of Untrusted Data
CVE: CVE-2020-36726

View all Ultimate Reviews vulnerabilities

At a glance

CVE-2020-36726 is a critical-severity Deserialization of Untrusted Data vulnerability in the Ultimate Reviews WordPress plugin, affecting versions < 2.1.33. It carries a CVSS score of 9.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 2.1.33; sites on affected versions should update now. Disclosed November 2020, reported by Jerome Bruandet.

Vulnerability Overview

The Ultimate Reviews plugin for WordPress is vulnerable to PHP Object Injection in versions up to, and including, 2.1.32 via deserialization of untrusted input in several vulnerable functions. This allows unauthenticated attackers to inject a PHP Object. No POP chain is present in the vulnerable plugin.

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, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-502: Deserialization of Untrusted Data

Reaching this weakness in Ultimate Reviews < 2.1.33 takes a caller who can reach the endpoint. Deserialization of untrusted data means the application reconstructs objects from input a caller controls, letting the attacker choose which classes get instantiated and what their properties hold.

A workable chain turns deserialization into file writes, deletions or code execution, depending on what the loaded classes do in their magic methods. For Ultimate Reviews the fix is 2.1.33: builds < 2.1.33 are affected, anything from 2.1.33 onward is not.

Remediation

Update to version 2.1.33, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Ultimate Reviews: WordSec's web application firewall inspects request payloads before WordPress loads them. Classes like this one can leave something behind, so the staged malware scanner is the second half: it looks for dropped files and modified code rather than for the request that created them. None of that substitutes for the fix: Ultimate Reviews 2.1.33 closes this, and updating the plugin is the step that ends it.

Firewall
Scanner
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2020-36726 https://www.wordfence.com/threat-intel/vulnerabilities/id/db30acd7-ce51-45d9-8ff0-6ceea8237a8c https://nvd.nist.gov/vuln/detail/CVE-2020-36726

Related records

Other vulnerabilities in Ultimate Reviews

CVSS Vector

9.8

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

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

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