Blog2Social <= 6.9.3 - PHP Object Injection

2022-04-05 00:00

Strategic Overview

Status: Patched in 6.9.4
Affected Plugin: Blog2Social: Social Media Auto Post & Scheduler
Affected Version: <= 6.9.3
CVSS: 8.5High
Weakness type: CWE-502 · Deserialization of Untrusted Data
CVE: CVE pending

View all Blog2Social: Social Media Auto Post & Scheduler vulnerabilities

At a glance

This record tracks a high-severity Deserialization of Untrusted Data vulnerability in the Blog2Social WordPress plugin, affecting versions <= 6.9.3. It carries a CVSS score of 8.5 (reachable over the network; high confidentiality, integrity, availability impact). The issue is fixed in version 6.9.4; sites on affected versions should update now. Disclosed April 2022.

Vulnerability Overview

The Blog2Social plugin for WordPress is vulnerable to PHP Object Injection in versions up to, and including 6.9.3 due to the use of unserialize on user supplied input retrieved from the 'b2s-post-meta-box-best-time-settings' and 'assignList' parameters.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, 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

Blog2Social <= 6.9.3 carries this weakness at b2s-post-meta-box-best-time-settings, 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 Blog2Social the fix is 6.9.4: builds <= 6.9.3 are affected, anything from 6.9.4 onward is not.

Remediation

Update to version 6.9.4, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Blog2Social: 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: Blog2Social 6.9.4 closes this, and updating the plugin is the step that ends it.

Firewall
Scanner
Alerts

External References

https://www.wordfence.com/threat-intel/vulnerabilities/id/02b61eb1-a93f-4437-87de-d698af8ef9f6

Related records

Same weakness class

7.4Blog2Social: Social Media Auto Post & Scheduler PHP Object Injection

Other vulnerabilities in Blog2Social: Social Media Auto Post & Scheduler

CVSS Vector

8.5

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

Base

Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredLow
User InteractionNone
ScopeChanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

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