Ice IX Malware Redirects Bank Phone Calls to Attackers

IBM research has discovered a concerning development in some new Ice IX configurations that are targeting online banking customers in the U.K. and U.S. Ice IX is a modified variant of the Zeus financial malware platform.

In addition to stealing bank account data, these configurations are capturing information on victims’ telephone accounts. This allows attackers to divert calls from the bank that were intended for its customers to attacker-controlled phone numbers. The fraudsters are presumably executing fraudulent transactions using the stolen credentials and redirecting the bank’s post-transaction verification phone calls to professional criminal caller services that approve the transactions.

How Ice IX Logs In

In one attack captured by IBM researchers, at the point of login the malware steals the victim’s user ID and password as well as the answers to the user’s memorable information/secret question, date of birth and account balance.

Next, victims are asked to update their recorded phone numbers (home, mobile and work) and select the name of their service provider from a drop-down list. In this particular attack, the three most popular phone service providers in the U.K. are presented: British Telecommunications (BT), TalkTalk and Sky. Here’s an example of the webinjection the user sees in his or her browser:

Example of the webinjection a user sees in his browser during an Ice IX attack

To enable the attacker to modify the victim’s phone service settings, the malware then asks the victim to submit his or her telephone account number. This is very private and sensitive data — typically only known to the phone subscriber and the phone company — and is used by the phone company to verify the identity of the subscriber and authorize sensitive account modifications such as call forwarding. The fraudsters justify this request by stating that the information is required as part of a verification process caused by “a malfunction of the bank’s anti-fraud system with its landline phone service provider.”

Here are the webinject messages presented to BT, Sky and TalkTalk users:

Webinject message presented by Ice IX malware to British Telecommunications (BT) users

Webinject message presented by Ice IX malware to Sky users

Webinject message presented by Ice IX malware to TalkTalk users

Fraudsters are increasingly turning to these post-transaction attack methods to hide fraudulent activities from the victim and block email and phone communication from the bank. This allows attackers to circumvent security mechanisms that look for anomalies once transactions have already been executed by the user.

Deterministic detection security mechanisms, like IBM Security Trusteer Rapport, search for specific malware crime logic footprints before transactions are submitted and allow the online banking application to stop fraud by changing business flows (block money transfers, decline/add payee, limit amounts, etc.). Uniquely, they are not vulnerable to post-transaction attacks.

Thanks to Tanya Shafir from the IBM analysis team for providing the intelligence for this post.


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Amit Klein

CTO, Trusteer, an IBM company

As Trusteer’s CTO, Amit Klein is responsible for researching and introducing game changing technologies into Trusteer’s products, with particular focus on Turtseer’s enterprise solutions. Prior to that, Mr. Klein established, managed and grew the company’s security group, which is one of the world’s leading financial malware research groups. Prior to Trusteer, Mr. Klein was Chief Scientist at Cyota Inc. (acquired by RSA Security), a leading provider of layered authentication solutions. In this role, Mr. Klein researched technologies that prevent online fraud, phishing, and pharming and filed several patents in those areas. Prior to this, Mr. Klein worked as Director of Security and Research at Sanctum, Inc. (acquired by Watchfire, now part of IBM Security Systems), where he was responsible for the security content of all Sanctum products. Mr. Klein holds a B.Sc. (cum laude) in Mathematics and Physics from the Hebrew University of Jerusalem (through IDF’s Talpiot programme). Mr. Klein is a world-renowned security researcher, having published more than thirty articles, papers and technical notes on the topic of Internet security. He was named CTO of the Year by InfoWorld Magazine and has presented at many prestigious conferences including RSA US, FSISAC, OWASP, Microsoft BlueHat, InterOp USA, AusCERT and CertConf.