CVE-2021-24145

Modern Events Calendar Lite <= 5.16.4 - Authenticated Arbitrary File Upload leading to Remote Code Execution

2021-01-29 00:00
Nguyen Van Khanh

Strategic Overview

Status
Patched in 5.16.5
Affected Plugin
Modern Events Calendar Lite
Affected Version
<= 5.16.4
CVSS
7.2High
Weakness type
CWE-434 · Unrestricted Upload of File with Dangerous Type
CVE
CVE-2021-24145
View all Modern Events Calendar Lite vulnerabilities

At a glance

CVE-2021-24145 is a high-severity Unrestricted Upload of File with Dangerous Type vulnerability in the Modern Events Calendar Lite WordPress plugin, affecting versions <= 5.16.4. 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. The issue is fixed in version 5.16.5; sites on affected versions should update now. Disclosed January 2021, reported by Nguyen Van Khanh.

Vulnerability Overview

Arbitrary file upload in the Modern Events Calendar Lite WordPress plugin, versions before 5.16.5, did not properly check the imported file, allowing PHP ones to be uploaded by administrator by using the 'text/csv' content-type in the request.

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 Modern Events Calendar Lite <= 5.16.4 takes any authenticated account. 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. For Modern Events Calendar Lite the fix is 5.16.5: builds <= 5.16.4 are affected, anything from 5.16.5 onward is not.

Remediation

Update to version 5.16.5, or a newer patched version

How does WordSec protect against this?

The attempt arrives as an ordinary request to Modern Events Calendar Lite: 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: Modern Events Calendar Lite 5.16.5 closes this, and updating the plugin is the step that ends it.

  • Firewall
  • Scanner
  • Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2021-24145https://www.wordfence.com/threat-intel/vulnerabilities/id/b9e67e3e-188c-4ca9-b846-d318859aeaf8https://nvd.nist.gov/vuln/detail/CVE-2021-24145

Related records

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