Unrestricted File Upload in WordPress WP Super Edit Plugin

WordPress Plugin WP Super Edit 2.5.4 and earlier contains an unrestricted file upload vulnerability in the FCKeditor component that allows attackers to upload dangerous file types without validation. Attackers can upload arbitrary files through the filemanager upload endpoint to achieve remote code execution and complete system compromise.

Casky was already ahead

This CVE exploits attack patterns that Casky's 419matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

CVE-2021-47965 is a critical unrestricted file upload vulnerability affecting WordPress Plugin WP Super Edit versions 2.5.4 and earlier. The vulnerability exists in the FCKeditor component's filemanager upload endpoint, which fails to validate uploaded file types before processing. This allows unauthenticated attackers to upload arbitrary files—including executable scripts—directly to the web server, leading to remote code execution and complete system compromise. Any WordPress installation using this vulnerable plugin becomes a direct target for attackers seeking initial access to web infrastructure, making this a high-priority remediation for website administrators.

Casky's 419 mapped skills leverage Claude's extended reasoning to detect the attack patterns underlying this vulnerability across the MITRE ATT&CK framework. Practitioners using Casky will identify reconnaissance activity (TA0001) as attackers probe for the vulnerable FCKeditor endpoint, followed by initial access exploitation (TA0001/TA0043) when malicious files are uploaded. The platform correlates indicators with resource development techniques (TA0042) to flag suspicious file staging and delivery mechanisms. During post-exploitation, Casky's skills detect execution patterns (TA0002) as uploaded shells or backdoors execute on the compromised server. Practitioners receive findings that connect suspicious HTTP POST requests to /wp-content/plugins/wp-super-edit/fckeditor/editor/filemanager/ paths, unexpected executable files appearing in web-accessible directories, and anomalous process spawning from web server processes—enabling rapid response before attackers establish persistence.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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Composite risk scoring from EPSS, CISA KEV, Shodan, and GreyNoise — 21 security APIs correlated into a single Casky Risk Score. Coming in Casky Pro. Join early access →

419 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2021-47965.

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malware analysis · medium

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MITRE ATT&CK Techniques

TA0001 TA0043 TA0002

Investigate the attack patterns behind CVE-2021-47965

Casky has 419 skills that investigate the attack patterns behind CVE-2021-47965. Run one and get CVSS-scored findings in 3 minutes.

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