Recently <= 3.0.4 - Arbitrary File Upload to Remote Code Exectution
Strategic Overview
- Status
- Patched in 3.0.5
- Affected Plugin
- Recently
- Affected Version
<= 3.0.4- CVSS
- 8.8High
- Weakness type
- CWE-434 · Unrestricted Upload of File with Dangerous Type
- CVE
CVE-2021-4382
At a glance
CVE-2021-4382 is a high-severity Unrestricted Upload of File with Dangerous Type vulnerability in the Recently WordPress plugin, affecting versions <= 3.0.4. It carries a CVSS score of 8.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). The issue is fixed in version 3.0.5; sites on affected versions should update now. Disclosed June 2021, reported by Jerome Bruandet.
Vulnerability Overview
The Recently plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in the fetch_external_image() function in versions up to, and including, 3.0.4. This makes it possible for authenticated attackers to upload arbitrary files on the affected site's server which may make remote code execution possible.
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
Recently <= 3.0.4 carries this weakness at fetch_external_image(), and reaching it 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. For Recently the fix is 3.0.5: builds <= 3.0.4 are affected, anything from 3.0.5 onward is not.
Remediation
Update to version 3.0.5, or a newer patched version
How does WordSec protect against this?
The attempt arrives as an ordinary request to Recently: 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: Recently 3.0.5 closes this, and updating the plugin is the step that ends it.
- Firewall
- Scanner
- Alerts
External References
Related records
Other vulnerabilities in Recently
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