What type of attack is Intruders exploiting a vulnerability in which no patch is yet available from the system vendor?

This type of attack is known as a zero-day exploit. Attackers take advantage of a previously unknown vulnerability in software or hardware for which no patch or fix has been released by the vendor. Since there is no defense available, these exploits can be particularly dangerous and effective. Organizations are often urged to implement security measures and monitoring to mitigate the risk associated with such vulnerabilities.