Tag Archives: Korea

PyeongChang 2018 Winter Olympics Opening Ceremony Disrupted by Malware Attack


The Pyeongchang Winter Olympics taking place in South Korea was disrupted over the weekend following a malware attack before and during the opening ceremony on Friday.

The cyber attack coincided with 12 hours of downtime on the official website for the Winter Games, the collapse of Wi-Fi in the Pyeongchang Olympic stadium and the failure of televisions and internet at the main press center, leaving attendees unable to print their tickets for events or get venue information.

The Pyeongchang Winter Olympics organizing committee confirmed Sunday that a cyber attack hit its network helping run the event during the opening ceremony, which was fully restored on 8 am local time on Saturday—that’s full 12 hours after the attack began.

Multiple cybersecurity firms published reports on Monday, suggesting that the cause of the disruption was “destructive” wiper malware that had been spread throughout the Winter Games’ official network using stolen credentials.

Dubbed “Olympic Destroyer” by the researchers at Cisco Talos, the wiper malware majorly focuses on taking down networks and systems and wiping data, rather than stealing information.

The Talos researchers would not comment on attribution, but various security experts have already started attributing the Olympic Destroyer malware to hackers linked to either North Korea, China or Russia.

According to the analysis by Cisco Talos, the attacker had intimate knowledge of the Pyeongchang 2018 network’s systems and knew a “lot of technical details of the Olympic Game infrastructure such as username, domain name, server name, and obviously password.”

“The other factor to consider here is that by using the hard-coded credentials within this malware it’s also possible the Olympic infrastructure was already compromised previously to allow the exfiltration of these credentials,” researchers said.

The Olympic Destroyer malware drops two credential stealers, a browser credential stealer and a system stealer, to obtain required credentials and then spreads to other systems as well using PsExec and Windows Management Instrumentation (WMI), two legitimate Windows administration tools used by network admins to access and carry out actions on other PCs on a network.

The researchers noted that both built-in tools were also abused by the Bad Rabbit ransomware and NotPetya wiper malware last year.

Once installed, the malware then first deletes all possible “shadow” copies of files and Windows backup catalogs, turn off recovery mode and then deletes system logs to cover its tracks and making file recovery difficult.

“Wiping all available methods of recovery shows this attacker had no intention of leaving the machine useable. The sole purpose of this malware is to perform destruction of the host and leave the computer system offline,” reads the Talos blog post.

It’s difficult to accurately attribute this cyber attack to a specific group or nation-state hackers due to sparse of technical evidence to support such a conclusion as well as hackers often employing techniques to obfuscate their operations.

South Korea hit with banking malware using VPN connection

South Korean banks have been attacked by hackers again!

This is not the first time we reported malware which targets Korean banking customers. In the past, we wrote about Chinese threats against Korean Windows users and last year we published a series of blogposts, Fake Korean bank applications for Android (part 1, part 2, part 3), about malware targeting mobile platforms.

The Korean banking malware is based on the same principle previously used. The customer executes the infected binary, which modifies Windows hosts file. This file contains a list of domains with assigned IP addresses.  Malware, however, may modify this file. When a customer wants to visit his online bank website, he is redirected to the IP address specified in the hosts file, not to the original bank website!

XP Debugging2

The piece of malware we will discuss in this blog post performs the above mentioned modification of system settings. However, when we looked into the modified hosts file, we noticed something unusual.


As you can see in the figure above (shortened screenshot of hosts file), the malware redirects many websites of South Korean banks to the IP address If you try to enter this address into your web browser, you probably won’t get any response, because this is the private IP address. The other websites which belong to South Korean search engines, like Naver, are redirected to the publicly accessible IP address. When visiting any of these search engines on the infected machine, the following banner is displayed on the top of the regular website.

popThe image says:

Do you have a security software or program in your PC or Do you have a security card? Due to hacking incidents and potential of compromising users’ information if you want to use internet banking you need to do identification procedure.

We found one very interesting technical detail about the malware behavior – it uses a VPN connection! When a user clicks on one of the bank’s logos below, he is connected to a VPN and the fake banking website is displayed. At first, the malware connects to the C&C server and obtains configuration by GET request on The C&C answer includes a link to an executable modifying the hosts file and VPN server IP address.


The executable is responsible for properly rewriting %windows%system32driversetchost file, which is queried for address translation before querying DNS on Windows machines. For example, if you want to go to www.naver.com the system first accesses the host file, and if there is a match it uses the specified IP address ( for that site which differs from the original DNS records – for our geographical location.

The malware targets Korean bank customers who access the following bank websites:

www.nonghyup.com, nonghyup.com, banking.nonghyup.com, www.nonghyup.co.kr, nonghyup.co.kr, banking.nonghyup.co.kr, www.shinhan.com, shinhan.com, www.shinhanbank.com, shinhanbank.com, www.shinhanbank.co.kr, shinhanbank.co.kr, banking.shinhanbank.com, banking.shinhan.com, banking.shinhanbank.co.kr, www.hanabank.com, hanabank.com, www.hanabank.co.kr, hanabank.co.kr, www.wooribank.com, wooribank.com, www.wooribank.kr, wooribank.kr, www.wooribank.co.kr, wooribank.co.kr, www.kbstar.com, kbstar.com, www.kbstar.co.kr, kbstar.co.kr, www.keb.co.kr, keb.co.kr, ebank.keb.co.kr, online.keb.co.kr, www.ibk.co.kr, ibk.co.kr, www.ibk.kr, ibk.kr, mybank.ibk.co.kr, banking.ibk.co.kr, www.kfcc.co.kr, kfcc.co.kr, www.kfcc.com, kfcc.com, www.epostbank.co.kr, epostbank.co.kr, www.epost.kr, epost.kr, www.epostbank.kr, epostbank.kr

The bank domain names are translated into a private network address range ( and the search engines are translated to webserver running IIS. Webserver runs a Chinese version of IIS, as shown from the error message displayed when supplying incorrect header information.

The malware, however, is not connected to the VPN all the time. The malware searches for the active Internet Explorer windows and if found, depending on Internet Explorer version, it locates browser’s address bar and extracts the currently entered url address. If URL belonging to any of the banks is found, VPN connection is established.

At first, malware drops a file %USERPROFILE%profiles.pbk, which includes the basic configuration. The credentials for VPN (name and password) are hard coded in the binary. The connection is made with help of Windows RAS API interface.


If we want to verify the VPN connection in Windows, we can simply locate the dropped PBK file and double click on it. In properties, we will choose “Prompt for name and passwords, certificate, etc.” We enter the username and password, which we previously extracted from the malicious binary. After pressing the “Connect” button, we are connected to the VPN, and if hosts file is properly modified, we can access the fake bank websites. After pressing “Hang Up”, we can disconnect from VPN.






After a successful connection, “ipconfig /all” command lists PPP connection to VPN, with the current machine’s assigned private IP address. At this moment, the infected machine is connected into the private network and it can access contents hosted on


Example of visiting bank’s website on a compromised computer

When a customer visits nate, daum or naver on an infected machine, he is presented with the following banner.
XP Debugging1

After clicking on the logo of a bank, the customer is presented with the following modified website (the example below was taken for epostbank.kr, however this attack works the same way for the other banks). If the customer clicks on any link on the fake bank website, he is presented with an error message. The message says that the additional security measures are available. After clicking OK, the fake verification process starts.
The customer is asked to fill in some personal details.
Then he is asked for a phone number and numbers in his security card.
Lastly, he is presented with a link to download a malicious Android application. At the writing of this blog post, the link to the malicious Android app is not working anymore.


Original dropper


Dropped DLL, C&C communication


Hosts file modifier




This analysis was jointly accomplished by Jaromir Horejsi, David Fiser and Honza Zika.

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