Group-IB, an international company that specializes in preventing cyber attacks, has established that Silence APT, a Russian-speaking cybercriminal group is likely to be behind the brazen attack on Dutch Bangla Bank’s ATMs resulting in the theft of $3 million, the amount reported by the local media. The actual amount of money stolen could be much higher. This is one of the Silence’s most recent international attacks which indicates that the gang has expanded its geography and has gone global, focusing now on APAC markets.
The final stage of the brash cyber attack, which started months earlier, took place in Dhaka on May 31, according to the local media reports. In CCTV footage posted by local newspapers two Ukrainian mules with covered faces are seen withdrawing money from the Dutch Bangla Bank’s ATMs. They were making phone calls every time before withdrawing money, which immediately prompted Group-IB’s Threat intelligence team’s interest and indicated that this could likely be be involvement of an organized financially cybercriminal group rather than simple skimming attack. By that moment, Group-IB Threat Intelligence team was already aware that Silence has been carrying out operations in Asia.
Group-IB has been tracking Silence and their infrastructure since 2016 and published a report “Silence: Moving into the darkside” in September 2018 which was the first to describe the group’s tactics and tools in detail. The information gathered by Group-IB’s Threat Intelligence team and comprehensive knowledge about Silence’s infrastructure suggested that Dutch Bangla Bank’s hosts with external IPs 184.108.40.206 and 220.127.116.11 were communicating with Silence’s C&C (18.104.22.168) since at least February 2019. During the attack on Dutch Bangla Bank cybercriminals have likely used the following Trojans – Silence.Downloader (aka TrueBot), Silence.MainModule (MD5 fd133e977471a76de8a22ccb0d9815b2) which allows to execute remote commands covertly and download files from the compromised server, and Silence.ProxyBot (MD5 2fe01a04d6beef14555b2cf9a717615c), which executes the tasks of the proxy server and allows the attacker to redirect traffic from the hidden node to the backconnect server via compromised PC.
Once they got access to the bank’s infrastructure, Silence went on to the next stage of the attack – money withdrawal. One of the instances was shown on the CCTV from May 31 published by the local media. Based on the TTPs used by Silence, the money could have been stolen two ways: the hackers could have either compromised the bank’s card processing system or used the custom Atmosphere software – a set of tools for ATMs jackpotting. The detailed description of Silence’s toolset is available in Group-IB’s report “Silence: Moving into the darkside”.
“What we see now is that Silence is continuing to shift their focus from CIS and neighbouring countries to international markets,” comments Rustam Mirkasymov, Head of Dynamic Analysis of Malicious Code at Group-IB. “Having tested their tools and techniques in Russia, Silence has gained the confidence and skill necessary to be an international threat to international banks and corporations. Asia particularly draws cybercriminals’ attention. Dutch Bangla Bank is not the first Silence’s victim in the region. In total, we are aware of at least 4 targets Silence attacked in Asia recently.”
Silence is an active though very small group of Russian-speaking hackers. Group-IB first detected the group’s activity in 2016. Over the course of their ‘work’, Silence attacked bank management systems, card processing systems, and the Russian interbank transfers system (AWS CBR). The gang’s targets are mainly located in Russia, Ukraine, Belarus, Azerbaijan, Poland, and Kazakhstan, although phishing emails were sent to bank employees in Central and Western Europe, Africa, and Asia.
Recently, Group-IB has detected Silence shifting their focus from the CIS and neighbouring countries to international markets. The report “Silence: Moving into the darkside” was published in September 2018 and was the first to describe the group’s tactics and tools.
About the author: Group-IB is a leading provider of solutions aimed at detection and prevention of cyberattacks, online fraud, and IP protection.
(SecurityAffairs – Silence APT, hacking)