Full Disclosure mailing list archives
Re: Privat24 (Facebook version) bypass of static password for accounts of PrivatBank (Ukraine, Russia and CIS)
From: Shreyas Zare <shreyas () secfence com>
Date: Mon, 11 Oct 2010 22:28:43 +0530
LOL. It must be quite convenient to use banking alongside FarmVille. Shreyas Zare Sr. Information Security Researcher Secfence Technologies www.secfence.com On Mon, Oct 11, 2010 at 3:57 AM, Andriy Tereshchenko <tag () 24 odessa ua>wrote:
1) Affected Service * Privat24 application in Facebook created by PrivatBank, Ukraine 2) Severity Rating: Moderate (need user actions or access to mobile phone) Impact: Exposure of sensitive financial information and unauthorized payment transactions Where: Remote (man in the middle), Local (removed authentication factor) 3) Vendor's Description of Service "Privat24 application in Facebook allows to view bank statement recent transactions on all your PrivatBank cards and account, refill mobile phones balance. More services to be added in future." Product Description Link: http://privatblog.com.ua/?p=269 Actual Product Link: http://apps.facebook.com/pb_transactions/ 4) Description of Vulnerability During registration process Facebook application ask for one-time-password from SMS message sent to mobile phone of registered Privat24 user. Once user name supplied proper OTP from SMS - his Facebook account ID is linked to ID of PrivatBank client. Vulnerabilities are: 1. SMS messages are not tagged in any way that they are from Privat24 (Facebook) system and no risks are described to client on disclosure of this OTP. 2. Secondary (mandatory) factor currently used on original non-Facebook Privat24 system ( http://privat24.ua ) is not used in this version of application. 3. Once linking/authorization process is done - no future SMS codes or passwords are needed to access application others that Facebook account login/password. 4. Client has no control on which Facebook accounts are linked to his financial information. Exploitation scenario: Attacker create fake Facebook accounts and link them to ID of Privat client. In order to link attacker need short-term access to the mobile phone (in order to receive SMS code) or setup fake website to ask for code from SMS (ex. eurovoice.tv SMS best-song voting process). After linking - attacker can access balances and statement on last transactions from all accounts of PrivatBank client. As well attacker can make small (tested are ~10 UAH) payments without any SMS passwords. 5) Solution a) SMS messages from Privat24 (Facebook) system should be tagged properly in order to allow users clearly identify service and website URL of SMS origin. b) SMS codes should be requested on each login to Privat24 (Facebook) application (at least once per day) or SMS notification be sent on login. c) Static (existing) password factor should be used in order to link Facebook account to client ID or visit to ATM for extra password is acceptable solution. Temporary solutions for current users offered by Rakaev Rostislav from bank support: Option 1: Protect your mobile phone using PIN/password from usage by wife/husband or co-workers. Never give it to unknown people. Option 2: Blacklist own phone-number for usage in PrivatBank Facebook applications by contacting 0 800 500 003 (for Ukraine) or online-chat support. 6) Timeline Postal mail letter addressed to author by PrivatBank from 03.05.2010 No. 30.1.0/2-100412/1849 describe intentions of PrivatBank to restore extra login factor (static password). Phone call from bank Security Department (Dnepropetrovsk) on 07.10.2010 with apology on inability to address issues due to conflict of interests with Electronic Business Department. Insecurity accepted as trade-off. 7) Credits Discovered by client of PrivatBank. 8) About The Commercial bank PrivatBank (Ukraine) was founded in 1992. Its services are used by more than 23% population of Ukraine population. PrivatBank currently serves 420 thousand corporate clients and small businesses, and over 13 million individual accounts. Moscomprivatbank Joint Stock Co. is subsidiary of PrivatBank. It has about 1.5 million credit cards issued. Privat24 is online-banking system used by more 1 million clients in Ukraine, Russia and CIS. 9) Links Privat24 (Facebook version) http://apps.facebook.com/pb_transactions/ Vendor announcement of service http://privatblog.com.ua/?p=269 Existing Privat24 system http://privat24.ua -- Andriy G. Tereshchenko Odessa, Ukraine +380683777768 _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
_______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/
Current thread:
- Privat24 (Facebook version) bypass of static password for accounts of PrivatBank (Ukraine, Russia and CIS) Andriy Tereshchenko (Oct 11)
- Re: Privat24 (Facebook version) bypass of static password for accounts of PrivatBank (Ukraine, Russia and CIS) Shreyas Zare (Oct 11)
- Re: Privat24 (Facebook version) bypass of static password for accounts of PrivatBank (Ukraine, Russia and CIS) Andriy Tereshchenko (Oct 11)
- Re: Privat24 (Facebook version) bypass of static password for accounts of PrivatBank (Ukraine, Russia and CIS) Andriy Tereshchenko (Oct 11)
- Re: Privat24 (Facebook version) bypass of static password for accounts of PrivatBank (Ukraine, Russia and CIS) Shreyas Zare (Oct 11)