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Online banking threats have been prevalent for many years, but recently they seem to be determined to expand beyond their usual targets. In the past few weeks and months, we’ve seen various attacks target Korean banks using various techniques.

The latest attack we’ve found uses a Trojan that redirects users of various Korean banks to malicious phishing sites. It does this by modifying the system’s HOSTS file and redirecting users to an IP address located in Japan. We detect the Trojan responsible for this attack as TSPY_QHOST.QFB, while the related batch file (which actually modifies the HOSTS file) is detected as BAT_QHOST.QFB. (This technique has been used for many years by other banking threats.)

The malicious site looks like this:

Figure 1. Page of malicious site

The malicious site has an additional window in the middle.

Figure 2. Additional window of malicious site

The image roughly translates to:

• Did you install the certificate of authentication in your PC (computer)?
• Are you using the security card for identification?

• You can safely use the Internet banking of WOORI-Bank if you obtain this security certificate.
• You will move to the security verification page, if you click the following button.
• Start Date: August – September Planned.

Unsuspecting users might believe they do need to perform this verification and thus click the button. Initially, the user will be directed to the following page that will ask for their name and Korean resident registration number:

Figure 3. Information is asked

The following screen asks for more information such as their cell phone number, account number, account password, user ID, user password, and certificate password:

Figure 4. Additional information is asked

These phishing sites abuse the trust that users have in their banks to get financial and personal information from users. They are made to think that they are entering their information in the bank’s real online banking site, when in fact they are not. Instead, the information ends up in the hands of the attackers who created this malware. (The phishing site and associated malware are all detected by Trend Micro products.)

While these may represent an evolution in terms of the chosen targets, the malware used is still not as sophisticated as what is typically used elsewhere. In addition, banking threats using various methods to steal information from Korean users have been seen multiple times recently.

Banking threats in general were described in our crimeware paper last year. However, it is likely that we will see these more sophisticated threats hit these banks in the future.