The ASEC analysis team is using the ASEC automatic analysis system RAPIT to categorize and respond to known malware. This post will list weekly statistics collected from May 17th, 2021 (Monday) to May 23rd, 2021 (Sunday).
For the main category, info-stealer ranked top with 75%, followed by RAT (Remote Administration Tool) malware with 19.3%, downloader with 3.6%, and ransomware with 2.1%.
Top 1 – AgentTesla
AgentTesla was ranked first place with 27.9%. It is an info-stealer malware that leaks user information saved in web browsers, e-mails, and FTP clients.
Recently collected samples use the following mail servers and user accounts when leaking the collected information.
- mail.transitworldexpress[.]com (192.185.119[.]206)
- smtp.babcockvalve[.]com (193.239.84[.]207)
- smtp.vivaldi[.]net (31.209.137[.]12)
As most are distributed through spam mails disguised as invoice, shipment document, and purchase order, the file names contain such words shown above (Invoice, Shipment, P.O. – Purchase Order). Some samples have extensions disguised as document files such as pdf and xlsx or Auto CAD blueprint files such as dwg.
- Bank Details.exe
- ship’s particulars – YAHA.xlsx.exe
- Updated Purchase Order.exe
- MV TOP DILIGENCE V.20S32.exe
- ORIGINAL SHIPPING DOCUMENT.PDF.exe
Top 2 – Lokibot
This week, Lokibot ranked second place with 14.8%. It is an info-stealer malware that leaks information about programs such as web browsers, mail clients, and FTP clients.
Being a malware that is distributed through spam mails, it shares similar distributed file names with other malware that are distributed through spam mails.
- MV PVT DIAMOND V.21089.exe
- SUPRA THESSAL VENDOR FORM.exe
- Purchase Order.exe
As shown in the below, most Lokibot malware C&C server URLs tend to end in fre.php.
Top 3 – Formbook
Formbook is an info-stealer malware ranked in third place with 12.6%.
Like other info-stealer malware, it is mainly distributed through spam mails. The distributed file names are close to each other.
- Swift_05182021 png.scr
- katalog produktów 2021_pdf.exe
As Formbook malware is injected in a normal process that is in the directory of explorer.exe and system32, the malicious behaviors are performed by the normal process. Besides web browser user account information, the malware can steal various information through keylogging, clipboard grabbing, and web browser form grabbing. Below is the list of confirmed C&C server URLs of Formbook.
Top 4 – CryptBot
For the first time, CryptBot malware was among the Top 5 malware, ranking fourth place with 11.0%. The malware is downloaded through PUP programs and has features of stealing additional information and downloading additional malware.
It is mainly distributed from phishing sites disguised as utility program download pages which are shown when searching certain keywords in Google.
The following are the confirmed C&C server URLs and additional malware download URLs of CryptBot.
- C&C 1: hxxp://morkqz03[.]top/index.php
C&C 2: hxxp://remkdi35[.]top/index.php
Download URL: hxxp://sulejx04[.]top/download.php?file=lv.exe
- C&C 1: hxxp://morkcx01[.]top/index.php
C&C 2: hxxp://sogdkz15[.]top/index.php
Download URL: hxxp://dousaj01[.]top/download.php?file=lv.exe
- C&C 1: hxxp://moreru07[.]top/index.php
C&C 2: hxxp://soguex75[.]top/index.php
Download URL: hxxp://doumbw10[.]top/download.php?file=lv.exe
The filenames distributed from phishing sites disguised as utility program download pages are as follows.
- P.O 3471.exe
- Bank Details.exe
Top 5 – NanoCore
NanoCore ranks fifth place with 6.7%. It is a RAT malware developed with .NET. Like njRAT, it can perform various commands given by the attacker such as information leakage including keylogging.
Similar to AgentTesla, Formbook, AveMaria, and Remcos, the NanoCore is packed with .NET packing and distributed through attached files in spam mails. As such, the file names reported are not much different from those of other malware distributed through spam mails.
- SCANNED DOCUMENTS_JPEG_IMG_ COPY_00213118570001.exe
- invoice copy.pdf.exe
The following list is the confirmed C&C server domains for NanoCore.