CVE-2020-35932

Newsletter <= 6.8.1 - Authenticated PHP Object Injection

2020-08-02 00:00

Strategic Overview

Status: Patched in 6.8.2
Affected Plugin: Newsletter – Send awesome emails from WordPress
Affected Version: < 6.8.2
CVSS: 7.5High
Weakness type: CWE-502 · Deserialization of Untrusted Data
CVE: CVE-2020-35932

View all Newsletter – Send awesome emails from WordPress vulnerabilities

At a glance

CVE-2020-35932 is a high-severity Deserialization of Untrusted Data vulnerability in the Newsletter WordPress plugin, affecting versions < 6.8.2. It carries a CVSS score of 7.5 (reachable over the network; high confidentiality, integrity, availability impact). Exploitation requires an authenticated account. The issue is fixed in version 6.8.2; sites on affected versions should update now. Disclosed August 2020, reported by Ram.

Vulnerability Overview

Insecure Deserialization in the Newsletter plugin before 6.8.2 for WordPress allows authenticated remote attackers with minimal privileges (such as subscribers) to use the tpnc_render AJAX action to inject arbitrary PHP objects via the options[inline_edits] parameter. NOTE: exploitability depends on PHP objects that might be present with certain other plugins or themes.

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

Reaching this weakness in Newsletter < 6.8.2 takes any authenticated account. 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 Newsletter the fix is 6.8.2: builds < 6.8.2 are affected, anything from 6.8.2 onward is not.

Remediation

Update to version 6.8.2, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Newsletter: 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: Newsletter 6.8.2 closes this, and updating the plugin is the step that ends it.

Firewall
Scanner
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2020-35932 https://www.wordfence.com/threat-intel/vulnerabilities/id/d684efcd-74fa-4b0c-b8dd-9674a2748fc3 https://nvd.nist.gov/vuln/detail/CVE-2020-35932

Related records

Other vulnerabilities in Newsletter – Send awesome emails from WordPress

CVSS Vector

7.5

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

Base

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

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