CVE-2021-24490

Email Artillery (MASS EMAIL) <= 4.1 - Arbitrary File Upload

2021-08-16 00:00
Jin Huang

Strategic Overview

Status
Unpatched
Affected Version
<= 4.1
CVSS
7.2High
Weakness type
CWE-434 · Unrestricted Upload of File with Dangerous Type
CVE
CVE-2021-24490
View all Email Artillery (MASS EMAIL) vulnerabilities

At a glance

CVE-2021-24490 is a high-severity Unrestricted Upload of File with Dangerous Type vulnerability in the Email Artillery (MASS EMAIL) WordPress plugin, affecting versions <= 4.1. It carries a CVSS score of 7.2 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). No fixed release has been reported yet; treat installations running this software as exposed. Disclosed August 2021, reported by Jin Huang.

Vulnerability Overview

The Email Artillery (MASS EMAIL) WordPress plugin through 4.1 does not properly check the uploaded files from the Import Emails feature, allowing arbitrary files to be uploaded. Furthermore, the plugin is also lacking any CSRF check, allowing such issue to be exploited via a CSRF attack as well. However, due to the presence of a .htaccess, denying access to everything in the folder the file is uploaded to, the malicious uploaded file will only be accessible on Web Servers such as Nginx/IIS

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-434: Unrestricted Upload of File with Dangerous Type

Reaching this weakness in Email Artillery (MASS EMAIL) <= 4.1 takes a caller who can reach the endpoint. An unrestricted file upload lets a caller store a file whose type or destination the application does not properly constrain.

If an uploaded file lands anywhere the server will execute, the flaw becomes remote code execution and the site should be treated as fully compromised. No fixed build of this plugin is recorded for Email Artillery (MASS EMAIL) yet, so installs running <= 4.1 stay exposed until the vendor ships one.

Remediation

No known patch available. Please review the vulnerability's details in depth and employ mitigations based on your organization's risk tolerance. It may be best to uninstall the affected software and find a replacement.

How does WordSec protect against this?

The attempt arrives as an ordinary request to Email Artillery (MASS EMAIL): 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. No patched version is recorded yet, which is the case where a filtering layer matters most, because there is nothing to update to.

  • Firewall
  • Scanner
  • Alerts

External References

Related records

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