Oracle databases have several well-known default username/password
combinations. These combinations include the following:

SCOTT/TIGER,
DBSNMP/DBSNMP  ------> ***
SYSTEM/MANAGER,
SYS/CHANGE_ON_INSTALL,
TRACESVR/TRACE,
CTXSYS/CTXSYS,
MDSYS/MDSYS,
DEMO/DEMO,
CTXDEMO/CTXDEMO,
APPLSYS/FND,
PO8/PO8,
NAMES/NAMES,
SYSADM/SYSADM,
ORDPLUGINS/ORDPLUGINS,
OUTLN/OUTLN,
ADAMS/WOOD,
BLAKE/PAPER,
JONES/STEEL,
CLARK/CLOTH,
AURORA$ORB$UNAUTHENTICATED/INVALID, and APPS/APPS.

These default combinations could allow an attacker to may provide unauthorized access to the server.