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 July 4th, 2022 (Monday) to July 10th, 2022 (Sunday).
For the main category, info-stealer ranked top with 43.9%, followed by downloader with 27.2%, backdoor with 21.1%, banking with 6.1%, ransomware with 1.1%, and coinminer with 0.6%.
Top 1 – AgentTesla
AgentTesla is an infostealer that ranked first place with 27.2%. It is an info-stealer that leaks user credentials saved in web browsers, emails, and FTP clients.
It uses e-mail to leak collected information, and there are samples that used FTP or Discord API. C&C information of recently collected samples is as follows.
- server : swlft-transportbd[.]com (193.239.84[.]207)
sender : taher@swlft-transportbd[.]com
receiver : taher@swlft-transportbd[.]com
user : taher@swlft-transportbd[.]com
pw : 2eO****tl
- server : filamenthubb[.]com (162.214.73[.]110)
sender : liton.chandra@newgengroupbd[.]com
receiver : marionhuntm@gmail[.]com
user : liton.chandra@newgengroupbd[.]com
pw : LiT****21a
- server : smtp.nutiribio[.]com (208.91.199[.]223)
sender : humhum@nutiribio[.]com
receiver : humhum@nutiribio[.]com
user : humhum@nutiribio[.]com
pw : zG****15
As most are distributed through spam emails disguised as invoices, shipment documents, and purchase orders, the file names contain such words shown above (Invoice, Shipment, P.O. – Purchase Order). Multiple collected samples were disguised as files with extensions of pdf and xlsx.
- E700 new order20111209.exe
- PO-0911254253364565009_JULY 2022.exe
- DHL AWB-COMMERCIAL INVOICE, BILL OF LADING, ETC DOC.exe
- SwiftMessage INVOICE 198208099.exe
- QuotationOrder (SCS).exe
- banco swift104##..exe
Top 2 – GuLoader
GuLoader, which ranked second place with 20.0%, is a downloader malware that downloads and runs additional malware. It was packed with Visual Basic language in the past to avoid detection, but it is now distributed in a form of NSIS installer. It used to be known as CloudEye, but got a name GuLoader because Google Drive is frequently used as a download URL. In addition to Google Drive, various URLs such as One Drive from Microsoft can also be used.
Instead of being downloaded in a file form, GuLoader is downloaded on memory to avoid detection, and downloaded file is encoded, not PE. It then runs after decoding in the memory, downloading malware such as infostealer (Formbook, AgentTesla) and RAT (Remcos, NanoCore).
As most are distributed through spam emails disguised as invoices, shipment documents, and purchase orders, 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.
- MV MASTER.exe
- R Order confirmation_20220707_1431_doc456670987640987236793289.xlsx_doc45667098.exe
Top 3 – Formbook
Formbook ranked third place with 12.8%.
Like other info-stealer, it is mainly distributed through spam emails. The distributed file names are close to each other.
- siparis 732022Yvvthilkr.exe
As Formbook is injected into two normal processes (one is explorer.exe and the other in system32 directory), the malicious behaviors are performed by the normal processes. Besides user credentials 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 4 – Remcos
This week, Remcos ranked fourth place with 6.7%. Remcos is a RAT malware that carries out various commands given by the attacker such as keylogging and information leaking.
Remcos is packed with a .NET packer and is distributed as attachments of spam mails, just like AgentTesla, Formbook, and NanoCore. Recently, there are some cases where it got distributed after disguising itself as a certain tool.
The confirmed C&C server URLs of Remcos are as follows.
Top 5 – Redline
RedLine ranked fifth place with 6.1%. The malware steals various information such as web browsers, FTP clients, cryptocurrency wallets, and PC settings. It can also download additional malware by receiving commands from the C&C server. Like BeamWinHTTP, there have been numerous cases of RedLine being distributed under the disguise of a software crack file.
The confirmed C&C server domains for RedLine are as follows:
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