Strategic Overview
- Status
- Unpatched
- Affected Plugin
- Business Hours Pro WordPress Plugin
- Affected Version
<= 5.5.0- CVSS
- 9.8Critical
- Weakness type
- CWE-434 · Unrestricted Upload of File with Dangerous Type
- CVE
CVE-2021-24240
At a glance
CVE-2021-24240 is a critical-severity Unrestricted Upload of File with Dangerous Type vulnerability in the Business Hours Pro WordPress Plugin WordPress plugin, affecting versions <= 5.5.0. It carries a CVSS score of 9.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires no authentication. No fixed release has been reported yet; treat installations running this software as exposed. Disclosed April 2021, reported by Harald Eilertsen.
Vulnerability Overview
The Business Hours Pro WordPress plugin through 5.5.0 allows a remote attacker to upload arbitrary files using its manual update functionality, leading to an unauthenticated remote code execution vulnerability.
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 privileges on the target site, 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 Business Hours Pro WordPress Plugin <= 5.5.0 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 Business Hours Pro WordPress Plugin yet, so installs running <= 5.5.0 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 Business Hours Pro WordPress Plugin: 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
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