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 EscribĂ for discovering these vulnerabilities and promptly bringing them to Oracle's attention.
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