Trustwave SpiderLabs Security Advisory TWSL2016-017:
SQL Injection Vulnerability in SAP Adaptive Server Enterprise

Published: 09/16/2016 
Version: 1.0

Vendor: SAP (www.sap.com)
Product: Adaptive Server Enterprise (ASE)
Version affected: 16.0 SP02 PL03

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

Finding 1: dbcc import_sproc SQL injection
Credit: Martin Rakhmanov of Trustwave 
CVE: CVE-2016-7402

SAP ASE 16.0 SP02 PL03 introduced a new DBCC command: dbcc import_sproc

Example invocation:

dbcc import_sproc('loopback', 'SourceDB', 'TargetDB')

Any database owner can run this DBCC statement by default.

Suppose a malicious user owns databases SourceDB and TargetDB on some server running ASE 16.0 SP02 PL03.

In that case he or she can elevate privileges to sa (system administrator) in a few simple steps:

In TargetDB create some dummy stored procedure via the CREATE PROCEDURE statement:

create procedure usp_demo as return

Replace the stored procedure body in syscomments with malicious T-SQL:

update syscomments set text = 'grant role sa_role to james--' where id = object_id('usp_demo')

Note that this requires ad-hoc updates to system catalog to be enabled which is 
not the default setting. But it can be easily bypassed by dumping the database, 
restoring the dump on another attacker-controlled server where ad-hoc updates are on, doing 
the update and then dumping and restoring back to the server being attacked.

Run dbcc import_sproc('loopback', 'TargetDB', 'SourceDB') while in SourceDB or 
TargetDB context which will execute T-SQL of attacker's choice with 
the highest privileges possible. Examine roles via sp_displayroles for role 
granted via the malicious T-SQL.

Remediation Steps:
Apply the SAP ASE 16.0 SP02 PL04 HF1 vendor supplied patch.  Please refer to SAP 
Security Note 2353243 for additional information.


Revision History:
06/02/2016 - Vulnerability disclosed to vendor
09/13/2016 - Patch released by vendor
09/16/2016 - Advisory published


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