Good morning,
We have found out a vulnerability through listener with some programs like nmap. As you can see bellow, running it we can see listener port and database version, which could be a big problem for our customer:
.\nmap.exe -p0- -v -A -T4 WIN-9H8TGULUPL1
1521/tcp open oracle-tns Oracle TNS listener 1.3.0.0.0 (unauthorized)
(only show 1, not 19, but it could be enough to have an attack)
.\nmap.exe -p0- -v -A -T4 vmNGF2
1521/tcp open oracle-tns Oracle TNS listener 12.2.0.1.0 (unauthorized)
.\nmap.exe -p0- -v -A -T4 vmNGF2
1523/tcp open oracle-tns Oracle TNS listener 12.2.0.1.0 (unauthorized)
We have checked this error since 10g version to 19c.
How we could restrict that information? I have already tested updating listener port, but we have same problem. Furthermore, we have update VALID_NODE_CHECKING_REGISTRATION_<listener_name> = ON but problem still happens.
If it helps, we're following OWASP 4 testing guide.
Thanks in advance.
Best regards