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 31st, 2021 (Monday) to June 6th, 2021 (Sunday).
For the main category, info-stealer ranked top with 82.5%, followed by RAT (Remote Administration Tool) malware with 16.0%, and downloader with 1.5%. Banking malware and ransomware were excluded due to decrease in the number of cases.
Top 1 – AgentTesla
AgentTesla was ranked first place with 29.4%. 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.
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.
- DHL.exe GE-726705.pdf.exe
- INVOICE PDF.exe
- New Order List.exe
- New Order Specifications xlsx.exe
- Payment Copy.exe
Top 2 – Formbook
Formbook is an info-stealer malware ranked in second place with 19.9%.
Like other info-stealer malware, it is mainly distributed through spam mails. The distributed file names are close to each other.
- 2103-004-I (BGP-0036) GEAR CASE B3-503597_JIANGSU SYD PROJECT.exe
- CONTRACT SWIFT.exe
- Failure Notice Details PDF.exe
- New price quotation.bat
- Order Specification.exe
- PO 0231.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 user account information in the web browser, 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 3 – Lokibot
This week, Lokibot ranked third place with 16.0%. 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.
- 20200237 Item List (84EA) – Specification Applied.exe
- 20200237 Item List -Specification Applied.xlsx.exe
- 20210531 Item List -Specification Applied-114578PZ75.exe
- 20210604133Order (New) Specification Applied10115.exe
- 20210604Order (New) Specification Applied_101157.exe
- 20210605Order (New) Specification Applied_101157.exe
- Balance Invoice-56400003970_pdf.exe
- Heeman Corporation_21531HY01.exe
- Heeman PO210601.exe
- Heeman quote.pdf.exe
- INSUNG PO196389.exe
- insung po9923458.exe
- Request of Quote 04-06-2021·pdf.exe
- SCAN JUNE’21.exe
As shown in the below, most Lokibot malware C&C server URLs tend to end in fre.php.
Top 4 – CryptBot
CryptBot malware ranked fourth place with 8.0%. 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&C1 : nimuvw35[.]top/index.php
C&C2 : morudl03[.]top/index.php
Download URL : noirsy04[.]top/download.php?file=lv.exe
- C&C1 : geobau75[.]top/index.php
C&C2 : moryce07[.]top/index.php
DownloadURL : rogkjs10[.]top/download.php?file=lv.exe
- C&C1 : geopfu25[.]top/index.php
C&C2 : moreok02[.]top/index.php
Download URL : rogmzx03[.]top/download.php?file=lv.exe
The filenames distributed from phishing sites disguised as utility program download pages are as follows.
Top 5 – NanoCore
NanoCore ranked fifth place with 6.3%. 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.
- RFQ – ship equipments and parts.exe
- swift copy 06032021.exe
- THUAN HIEP THANH CO – PURCHASE ORDER.exe
The following list is the confirmed C&C server domains for NanoCore.