CVE-2023-6620

POST SMTP Mailer – Email log, Delivery Failure Notifications and Best Mail SMTP for WordPress <= 2.8.6 - Authenticated (Administrator+) SQL Injection

2023-12-21 00:00
Alex Sanford

Strategic Overview

Status
Patched in 2.8.7
Affected Plugin
Post SMTP – Complete Email Deliverability and SMTP Solution with Email Logs, Alerts, Backup SMTP & Mobile App
Affected Version
<= 2.8.6
CVSS
7.2High
Weakness type
CWE-89 · Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')
CVE
CVE-2023-6620
View all Post SMTP – Complete Email Deliverability and SMTP Solution with Email Logs, Alerts, Backup SMTP & Mobile App vulnerabilities

At a glance

CVE-2023-6620 is a high-severity Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection') vulnerability in the Post SMTP WordPress plugin, affecting versions <= 2.8.6. It carries a CVSS score of 7.2 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires an authenticated account at Administrator level or above. The issue is fixed in version 2.8.7; sites on affected versions should update now. Disclosed December 2023, reported by Alex Sanford.

Vulnerability Overview

The POST SMTP – The #1 WordPress SMTP Plugin with Advanced Email Logging and Delivery Failure Notifications plugin for WordPress is vulnerable to time-based SQL Injection via the selected parameter in all versions up to, and including, 2.8.6 due to insufficient escaping on the user supplied parameter and lack of sufficient preparation on the existing SQL query. This makes it possible for authenticated attackers with administrator access or higher to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database.

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 confidentiality, integrity, availability — full site compromise territory.

CWE-89: Improper Neutralization of Special Elements used in an SQL Command ('SQL Injection')

Reaching this weakness in Post SMTP <= 2.8.6 takes an account at Administrator level or above. SQL injection happens when request data is concatenated into a query instead of being bound as a parameter, letting an attacker change the structure of the statement rather than just its values.

A working injection can read any table the database user can see, which on a WordPress install means user records, password hashes and session or API secrets stored in options. For Post SMTP the fix is 2.8.7: builds <= 2.8.6 are affected, anything from 2.8.7 onward is not.

Remediation

Update to version 2.8.7, or a newer patched version

How does WordSec protect against this?

An attacker needs Administrator access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Post SMTP 2.8.7 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2023-6620https://www.wordfence.com/threat-intel/vulnerabilities/id/a317395b-32ab-4a00-9568-b87d7c4f69a6https://nvd.nist.gov/vuln/detail/CVE-2023-6620

Related records

Vulnerability data © Defiant, Inc., provided under the Wordfence Intelligence T&C