Pierluigi Paganini
August 28, 2019
Trend Micro revealed that the TA505 group that is behind the Dridex and Locky malware families continue to make small changes to its operations. TA505 hacking group has been active since 2014 focusing on Retail and banking sectors. The group is also known for some evasive techniques they put in place over time to avoid the security controls and penetrate corporate perimeters with several kinds of malware, for instance abusing the so-called LOLBins (Living Off The Land Binaries), legit programs regularly used by
TA505 is now expanding the list of countries and entities targeted with its malware and it is modifying techniques to deploy malicious code.
“Given the group’s active campaigns since our updates in June and July, we continued following their latest campaigns. Just like in previous operations, they continue to make small changes, such as targeting other countries, entities, or the combination of techniques used for deployment, for each campaign.” reads the analysis published by TrendMicro.
The cyber criminals continue to use both FlawedAmmyy RAT or the ServHelper backdoor. In the last nine campaigns since June, the threat actors also started using
The cybercrime gang is also expanding the list of countries, recent
In the middle of July, Trend Micro observed for the first time attacks leveraging
Another attack observed by the experts leveraged an Excel document
TA505 also used in one attack an updated version of ServHelper that included the strings’ binary encrypted in Vigenère cipher. Experts observed that some samples still had errors in the cipher routine.
Malware researchers also discovered that the code included two new backdoor commands,
Experts believe that developers behind ServHelper continued to upgrade their malicious code to evade detection and implements more functions.
Another attack documented by Trend Micro sees attackers employing a
The TA505 also targeted government agencies in Saudi Arabia, Oman, and Qatar using another type of .XLS or .DOC attachments. and which used emails with subjects pertaining to finance or urgent concerns on insurance policies.
“We found another routine from a campaign targeting government agencies in Saudi Arabia, Oman, and Qatar with another type of .XLS or .DOC attachment. The emails used in these campaigns used subjects pertaining to finance or urgent concerns on insurance policies.” continues the report.
“A similar campaign targeting Turkish educational and government institutions used email subjects pertaining to invoice information or personnel payroll, and Visual Basic for Applications (VBA) .XLS or VBA .DOC macros.”
Earlier this month, the TA505 group was delivering a .DLL variant of the FlawedAmmyy RAT to targets in Canada that includes several updates, such as one that attempts to bypass detection rules.
It is interesting to note that experts observed a suspicious activity using ServHelper in attacks targeting China. In this
“The changes and adjustments that TA505 made from the original ServHelper and FlawedAmmyy routines may indicate that the group is experimenting and testing to determine which forms of obfuscation can bypass detections, resulting in more financial returns. It’s also possible that the changes in target countries and industries are driven by the group’s customers; targeting new victims and even returning to previously targeted countries and organizations with new techniques. This also gives TA505 more data on which types of files can be further used for detection evasion, or even to deter attribution.” Trend Micro concludes.
“Given the frequency of changes in routines and deployment from our previous articles, we can expect TA505 to come up with more methods for payload delivery, malware types, and combinations of previously used and new routines.”
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