Oracle File Overwrite Security Vulnerability

[Oracle Security Alerts <secalert_us () oracle com>]

Security Alert #20
Reference Date: 10/18/01

Oracle File Overwrite Security Vulnerability

Overview
There is a potential security vulnerability associated with the Oracle
binary oracle on UNIX platforms. A non-privileged user (such as
“nobody”) invokes the oracle executable: as a result of the presence of
the SETUID bit, the executable can be forced to write to a trace file in
ORACLE_HOME/rdbms/log directory and thereby overwrite existing log files
or create new (unauthorized) files. The non-privileged user can also
point the environment variable, ORACLE_HOME, to an arbitrary directory
in the operating system and thereby corrupt other files as well.

Products
All Oracle database server releases (8.0.x, 8.1.x and 9.0.1)

Platforms
All Unix platforms

Workaround
Change the file permissions on the oracle executable as follows:
% chmod o-x oracle

Notes
The workaround suggested above will permit only the owner of the oracle
executable and users defined in the OS DBA group to run the oracle
executable directly. With the execute permissions for “others” removed,
other users cannot connect to an Oracle database server using the BEQ
driver. If the BEQ driver is being used to connect to an Oracle
database, a client program (such as SQLPLUS) will fork its processes and
try to execute the oracle executable directly. This operation will fail
because such a client program will run with the OS user’s privileges who
no longer has execute permission on the oracle executable. To avoid this
problem, local users
must connect to an Oracle database using the IPC driver which makes it
possible to connect to a TNS listener listening on an Oracle database.
The TNS listener will need to be started by a user that has execute
permissions on the oracle executable.

Patches
The potential security vulnerability will be code-fixed in the next
release of the Oracle database server which is Oracle9i, Release 2,
only. All other releases of the Oracle database (8.0.x, 8.1.x and 9.0.1)
must use follow the workarounds specified above to circumvent the
potential security vulnerability.

Credits
Oracle wishes to thank Juan Manuel Pascual Escribà for discovering these
vulnerabilities and promptly bringing them to Oracle's attention.