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 August 1st, 2022 (Monday) to August 7th, 2022 (Sunday).
For the main category, info-stealer ranked top with 47.4%, followed by backdoor with 22.6%, downloader with 20.0%, ransomware with 6.8%, banking with 2.6%, and CoinMiner with 0.5%.
Top 1 – Agent Tesla
AgentTesla is an infostealer that ranked first place with 25.8%. 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: mail.activandalucia[.]com (185.162.171[.]75)
- server: smtp.dhavaldistilevap[.]cam (208.91.198[.]143)
- server: mail.enmark.com[.]my (110.4.45[.]145)
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.
- URGENT REQUIREMENT.exe
- AWD 0926317468 DHL SHIPPING DOCUMENTS.exe
- Bank Slip #eo0012it90019999prt0001.exe
- SWIFT TRANSFER-00298760.exe
- Swift – 21,700 – 060296.exe
- E700 quotation20111209.exe
- DECLARATIE EXPORT UK1RO-0108DSV_0381.exe
- PO 2220802-031A.exe
Top 2 – Formbook
Formbook ranked second place with 15.3%.
Like other info-stealers, it is mainly distributed through spam emails. The distributed file names are close to each other.
- Pre Alert Docs.exe
- Сатып алуға тапсырыс.exe
- PRE-ALERT IOF22-23BLB1399.exe
Formbook is injected into normal processes (one is a running explorer.exe and the other in system32) that performs malicious behaviors. 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 3 – Guloader
GuLoader, which ranked third place with 9.5%, 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 is now distributed in a form of 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.
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 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.
- DHL_229140 documento de recebimento,pdf.exe
- order samples.bat
- Purchase Order – 12994-.exe
Top 4 – RedLine
RedLine ranked fourth place with 9.5%. 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 following are the confirmed C&C server domains for RedLine:
Top 5 – Stop Ransomware
Lastly, Stop Ransomware ranked fifth place with 6.8%. It is malware that is distributed mainly using exploit kits. This malware encrypts certain files in user PCs. It has been distributed in various forms since the past. The recently distributed samples perform ransomware behavior by installing Vidar, which is an infostealer.
The following is the C&C server URLs of Stop ransomware.
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