Perhaps most ironic for ad server software, nulled versions frequently inject their own advertisements—often of questionable quality. These might include gambling ads, scam promotions, or even malicious downloads masquerading as legitimate software.
If the script encounters a database error or a memory leak, you have no access to official customer support to fix it.
The Sucuri research team has documented numerous cases where nulled plugins and themes came with backdoors, hidden links, unwanted ads, and even pure malware such as CryptoPHP or fake jQuery scripts designed to compromise entire servers.