The ASEC analysis team uses the ASEC automatic analysis system RAPIT to categorize and respond to known malware. This post will list weekly statistics collected from January 2nd, 2023 (Monday) to January 8th, 2023 (Sunday).
For the main category, downloader ranked top with 55.9%, followed by Infostealer with 21.3%, backdoor with 14.2%, ransomware with 7.9%, and CoinMiner with 0.8%.
Top 1 – BeamWinHTTP
BeamWinHTTP is a downloader malware that ranked top with 32.3%. The malware is distributed via malware disguised as PUP installer. When it is executed, it installs PUP malware Garbage Cleaner and can download and install additional malware at the same time.
Top 2 – SmokeLoader
SmokeLoader is an Infostealer/downloader malware that is distributed via exploit kits. This week, it ranked second place with 22.0%. Like other malware that is distributed via exploit kits, this malware also has a MalPe form.
When executed, it injects itself into explorer.exe, and the actual malicious behavior is executed by explorer.exe. After connecting to the C&C server, it can download additional modules or other malware strains. Additionally downloaded modules usually have Infostealer features, and explorer.exe (child process) is created and injects modules to operate.
For an analysis report related to Smoke Loader, refer to the ASEC Report below.
The confirmed C&C server URLs are as follows.
Top 3 – AgentTesla
AgentTesla is an Infostealer that ranked third place with 6.3%. It leaks user credentials saved in web browsers, emails, and FTP clients.
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.
- Telegram API : hxxps://api.telegram[.]org/bot5932499274:AAFVgY_mSAbCu0fXfBWMuUmyk56JtTf6–Q/
- SMTP Server : gmail.com
User : email@example.com
Password : hn********abdsss
Receiver : firstname.lastname@example.org
- SMTP Server : host39.registrar-servers.com
User : Account@nachnegg.net
Password : P*********45
Receiver : Account@nachnegg.net
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.
Top 4 – Formbook
Formbook ranked fourth place with 5.5% (tied with Mallox).
Like other Infostealers, it is mainly distributed through spam emails. The distributed file names are close to each other.
- sipariş pdf.exe
- Banco Atlantico_SWIFT208_eEXT…….3-FEB-2021_9bb08cb7292ai1.exe
- About Us – MS-Group.exe
- MS – Group Projects.exe
- teklif siparişi pdf.exe
- INVOICE CORRECTION.png.scr
- Camscanner.New Order.09878766.exe
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.
Top 4 – Mallox
Mallox also ranked fourth place with 5.5% (tied with Formbook). Mallox is a ransomware that is mainly distributed to vulnerable MS-SQL servers to perform file encryption.
Mallox Ransomware is injected into a normal process to be executed, and as it is usually distributed to vulnerable MS-SQL servers, it terminates SQL server-related processes. It also carries URLs to download additional malware.
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