Critical vulnerability in Popular Posts plugin allows uploading malicious file to hack WordPress websites

Cybersecurity specialists report the detection of a critical vulnerability in Popular Posts, a plugin for the content management system (CMS) WordPress. According to the report, the successful exploitation of this flaw would allow threat actors to deploy multiple risk scenarios.  

Tracked as CVE-2021-42362, this flaw exists due to improper file validation during upload to ~/src/Image.php, which would allow remote threat actors to upload a malicious file for execution on the compromised server.

The flaw received a score of 7.7/10 according to the Common Vulnerability Scoring System (CVSS) and its successful exploitation would put the entire vulnerable system at risk, according to experts.

Up next are all affected versions of WordPress Popular Posts: 1.0, 1.0.0, 1.1, 1.1.0, 1.2, 1.2.0, 1.3, 1.3.0, 1.3.1, 1.3.2, 1.4.0, 1.4.1, 1.4.2, 1.4.3, 1.4.4, 1.4.5, 1.4.6, 1.5.0, 1.5.1, 1.5.2, 2.0.0, 2.0.1, 2.0.2, 2.0.3, 2.1.0, 2.1.1, 2.1.2, 2.1.3, 2.1.4, 2.1.5, 2.1.6, 2.2.0, 2.2.1, 2.3.0, 2.3.1, 2.3.2, 2.3.3, 2.3.4, 2.3.5, 2.3.6, 2.3.7, 3.0.0, 3.0.1, 3.0.2, 3.0.3, 3.0.4, 3.1.0, 3.1.1, 3.1.2, 3.2.0, 3.2.1, 3.2.2, 3.2.3, 3.3.0, 3.3.1, 3.3.2, 3.3.3, 3.3.4, 4.0.0, 4.0.1, 4.0.2, 4.0.3, 4.0.5, 4.0.6, 4.0.7, 4.0.8, 4.0.9, 4.0.10, 4.0.11, 4.0.12, 4.0.13, 4.1.0, 4.1.1, 4.1.2, 4.2.0, 4.2.1, 4.2.2, 5.0.0, 5.0.1, 5.0.2, 5.1.0, 5.2.0, 5.2.1, 5.2.2, 5.2.3, 5.2.4, 5.3.0, 5.3.1 & 5.3.2.

While the vulnerability could be exploited remotely by unauthenticated malicious hackers, the researchers mention that so far no active exploitation attempts or the existence of a malware variant associated with the attack have been detected. Still, administrators of affected deployments are encouraged to upgrade as soon as possible to fully mitigate exploitation risk; updates are now available.

To learn more about information security risks, malware variants, vulnerabilities and information technologies, feel free to access the International Institute of Cyber Security (IICS) websites.