Furthermore, PCI DSS (Payment Card Industry Data Security Standard) requires that all code on your server be secure and known. A nulled theme violates PCI compliance immediately, meaning you could lose your ability to process credit cards entirely. A common myth is: "I scanned it with VirusTotal, and it found nothing."
But Google will. Google’s crawlers will detect the malicious outbound links, and your site will be flagged with the dreaded red warning: "This site may be hacked." Once you're on Google's blacklist, organic traffic dies instantly, and recovery takes months. Opencart itself releases security patches. Legitimate theme developers update their themes to stay compatible and patch vulnerabilities. Opencart Nulled Themes
The short answer:
It sounds tempting. Why pay $59 for a theme when you can get it for free? Furthermore, PCI DSS (Payment Card Industry Data Security