ASEC Weekly Malware Statistics (March 6th, 2023 – March 12th, 2023)

Malware Analysis
1

AhnLab Security response Center (ASEC) uses the ASEC automatic analysis system RAPIT to categorize and respond to known malware. This post will list weekly statistics collected from March 6th, 2023 (Monday) to March 12th, 2023 (Sunday).

For the main category, Infostealer ranked top with 52.6%, followed by backdoor with 27.6%, downloader with 15.7%, ransomware with 3.0%, CoinMiner with 0.7%, and banking malware with 0.4%.


Top 1 – AgentTesla

AgentTesla is an infostealer that ranked first place with 25.4%. It leaks user credentials saved in web browsers, emails, and FTP clients.

How AgentTesla Malware is Being Distributed in Korea

Although it uses emails (a.k.a. SMTP protocol) to leak collected information, there are samples that used FTP or Telegram API. The C&C information of recently collected samples is as follows.

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, and P.O. – Purchase Order). Multiple collected samples were disguised as files with extensions of pdf and xlsx.

  • QUOTATION #QO210421A87356.exe
  • Technical Sheet And P.O.exe
  • nova ordem.XLSx_______________________________.exe
  • PAGO FACTURA 3802.exe
  • DHL SHIPPING INVOICE COPYS.exe
  • Deposit slip.exe


Top 2 – RedLine

RedLine malware ranked second place with 23.1%. 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.

Infostealer Being Distributed via YouTube

The following are the confirmed C&C server domains for RedLine:

  • hxxp://hueref[.]eu:4162/
  • hxxp://193.233.20[.]27:4123/
  • hxxp://45.138.74[.]121:80/
  • hxxp://81.19.141[.]8:14701/
  • hxxp://82.115.223[.]46:57672/


Top 3 – SnakeKeylogger

Taking third with 13.4%, SnakeKeylogger is an Infostealer that leaks information such as user key inputs, system clipboards, and browser account information.

Snake Keylogger Being Distributed via Spam E-mails

Like AgentTesla, this malware uses e-mail servers and user accounts when leaking collected information. The following is the accounts used by recently collected samples.

  • hxxps://api.telegram[.]org/bot5310184099:AAGxqu0IL8tjOF6Eq6x2u0gfcHhvuxRwfLU/sendDocument?chat_id=5350445922
  • hxxps://api.telegram[.]org/bot5568312416:AAHFcV7Sj5ZHvpqi5PHfNfJ6Z7VDXDyymUI/sendDocument?chat_id=1884866272
  • hxxps://api.telegram[.]org/bot6112875567:AAELAi1dztc_XKpDFEg1a1IG01250o2gxXs/sendDocument?chat_id=5687933537
  • FTP Host : hxxp://www.213221321[.]com
    Username : root
    Password : 1*************


Top 4 – Formbook

Formbook is an Infostealer that ranked fourth place with 9.7%.

Like other Infostealers, it is mainly distributed through spam emails. The distributed file names are close to each other.

  • DHL.exe
  • Bill of Lading Toll – TTPE6214848………………………………………..exe
  • 3DC Project Marterials.exe
  • 03-07 GW consolution Bill Of Lading – 6040279326.scr

As Formbook is injected into normal processes (one is a running explorer.exe and the other is in system32), the malicious behaviors are performed by these 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.

  • hxxp://www.tomart[.]live/onpq/
  • hxxp://www.momarketing[.]xyz/nnbh/
  • hxxp://www.kitefig[.]online/us8k/
  • hxxp://www.bleclear[.]xyz/erh1/
  • hxxp://www.arrmart[.]life/gefg/


Top 5 – Guloader

GuLoader, which ranked fifth place with 8.2%, is a downloader malware that downloads additional malware and runs it. It was packed with Visual Basic language in the past to bypass detection, but it is now distributed in a form of an NSIS installer. It used to be known as CloudEye but got the 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 and Discord can also be used.

  • hxxps://drive.google[.]com/uc?export=download&id=1DT71DDf06jofYuWCFagrInsDMI08lUwU
  • hxxps://drive.google[.]com/uc?export=download&id=1yItocWkQEKby7n8DJtBTHjYu65QKBpF5
  • hxxps://drive.google[.]com/uc?export=download&id=1YF33ame0BzqR3-8q7MeMR6YEkqd4Pwmq
  • hxxps://onedrive.live[.]com/download?cid=89B6297861C1EBB8&resid=89B6297861C1EBB8%21117&authkey=AOkty2sYT6EDUBQ

Instead of being downloaded in a file form, GuLoader is downloaded on memory to avoid detection, and the downloaded file is encoded, not PE. It is then executed after being decoded in the memory, downloading malware such as Infostealers (Formbook and AgentTesla) and RAT (Remcos and 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, and 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.

  • ADV_9903119166.exe
  • SWIFT 5907275.exe
  • IRQ2207799_pdf.exe
  • Payment Swift.exe
  • Diphtherian.exe

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