CVE-2022-2434

String Locator <= 2.5.0 - Cross-Site Request Forgery to PHAR Deserialization

2022-08-08 00:00
Rasoul Jahanshahi

Strategic Overview

Status
Patched in 2.6.0
Affected Plugin
String locator
Affected Version
<= 2.5.0
CVSS
8.8High
Weakness type
CWE-502 · Deserialization of Untrusted Data
CVE
CVE-2022-2434
View all String locator vulnerabilities

At a glance

CVE-2022-2434 is a high-severity Deserialization of Untrusted Data vulnerability in the String locator WordPress plugin, affecting versions <= 2.5.0. It carries a CVSS score of 8.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. The issue is fixed in version 2.6.0; sites on affected versions should update now. Disclosed August 2022, reported by Rasoul Jahanshahi.

Vulnerability Overview

The String Locator plugin for WordPress is vulnerable to deserialization of untrusted input via the 'string-locator-path' parameter in versions up to, and including 2.5.0. This makes it possible for unauthenticated users to call files using a PHAR wrapper, granted they can trick a site administrator into performing an action such as clicking on a link, that will deserialize and call arbitrary PHP Objects that can be used to perform a variety of malicious actions granted a POP chain is also present. It also requires that the attacker is successful in uploading a file with the serialized payload.

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. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-502: Deserialization of Untrusted Data

String locator <= 2.5.0 carries this weakness at string-locator-path, and reaching it 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 String locator the fix is 2.6.0: builds <= 2.5.0 are affected, anything from 2.6.0 onward is not.

Remediation

Update to version 2.6.0, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to String locator: 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: String locator 2.6.0 closes this, and updating the plugin is the step that ends it.

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External References

Related records

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