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||Potential Vulnerabilities in Oracle Internet Application Server
||25th December 2000
Potential Vulnerabilities in Oracle Internet Application Server
The first potential vulnerability is found in the WebDB/Portal component
of Oracle Internet Application Server (iAS) Listener and modplsql, up to
and including release 3.0.7 (associated modplsql version is 22.214.171.124.1).
The second potential vulnerability affects all versions of the PL/SQL
gateway including Oracle Application Server (OAS), the WebDB/Portal
listener, and iAS.
The first possible vulnerability is essentially a configuration issue
associated with the Portal Listener and modplsql. When these are
installed, the default configuration allows all users access to the
Listener and modplsql administration pages.
A second potential vulnerability may occur if customers grant public
access to PL/SQL procedures, in particular those which access an Oracle
database such as OWA, SYS and DBMS. Since publicly accessible
procedures may be accessed through a URL, it may be possible to to
invoke these procedures through a URL and cause SQL statements to be
executed on a back-end Oracle database.
Likelihood of Occurrence:
The first vulnerability may occur if the default permission for admin
pages is not changed after WebDB/Portal install. The second
vulnerability depends on the design of applications which use the PL/SQL
gateway, but may occur whenever procedures are granted public access.
The first vulnerability may allow unauthorized access to administrative
pages. The second vulnerability may allow unauthorized access to data
within a back-end Oracle database.
The workaround for the first vulnerability is to specify that the
Listener and modplsql administrator must be one or more known users.
This may be done by simply editing the wdbsvr.app configuration file on
WebDB/Portal. All versions of the Listener and modplqsl use this file;
at the top of the file is a setting entitled 'administrators='.
Customers should set this property to specify one or more named users
who are allowed to have administrative privileges.
In addition, customers can change the path used to reference the admin
pages. By default this path is 'admin_', but can be changed in the
wdbsvr.app file to something else (e.g., changing it to 'foo' would
change the admin page URL to
Customers who have granted public access to PL/SQL procedures on
WebDB/Portal can mitigate the risk associated with second vulnerability
in two ways.
The first is to revoke public access to procedures such as OWA, SYS and
DBMS which can potentially execute user-specified SQL statements.
For modplsql in iAS, a second solution is to disable access to URLs
which match certain criteria. For example, in the case of SYS, OWA, and
DBMS this may be done by adding the following rules to the plsql.conf
# Disallow direct access to any PL/SQL procedure in the SYS schema, in
Deny from all
# Disallow direct access to any DBMS* PL/SQL procedure which is called
thru public synonyms:
Deny from all
# Disallow direct access to any owa_util procedure:
Deny from all
Note that since Apache treats these rules as case sensitive, the first
rule prevents access to any URL including sys.*, but would allow access
to URLs with SYS.* or Sys.*. It may be therefore be necessary to
include additional rules with different case combinations in the names
of the procedures (e.g., repeat rule 1 in the config. file, substituting
SYS.*, Sys.*, etc. for sys.*).
Note also that the plsql.conf file can be configured to include rules
which prevent access to URLs containing specific SQL statements such as
select, insert, grant, etc., keeping in mind that rules are case
Release 3.0.8 of Portal will restrict default access to the Listener and
modplsql admin pages on installation.
Oracle is developing enhancements for iAS which will allow customers to
define case insensitive rules to disable access to certain procedures