ASEC Weekly Malware Statistics (July 25th, 2022 – July 31st, 2022)

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 25th, 2022 (Monday) to July 31st, 2022 (Sunday).

For the main category, info-stealer ranked top with 38.6%, followed by backdoor with 38.1%, and downloader with 23.3%.

Top 1 – Agent Tesla

AgentTesla is an infostealer that ranked first place with 23.8%. It is an info-stealer that leaks user credentials saved in web browsers, emails, and FTP clients.

How AgentTesla Malware is Being Distributed in Korea

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.

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.

  • SHipping documents.exe
  • ftkbeaep.exe
  • Purchase Order_Request for QUOTE Specs.exe
  • 220077 INVOICE.exe
  • Img-08052020.exe
  • Payment Advice.exe
  • DHL SHIPMENT NOTIFICATION.exe

Top 2 – RedLine

RedLine malware ranked second place with 21.2%. 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:

  • 62.204.41[.]144
  • 31.41.244[.]134
  • trustamsty[.]com
  • 103.89.90[.]61
  • 185.106.92[.]226
  • lunovim957.duckdns[.]org

Top 3 – GuLoader

GuLoader, which ranked third place with 11.6%, is a downloader malware that downloads additional malware and runs it. It was packed with Visual Basic language in the past to bypass detection, 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 can also be used.

  • hxxp://3sixtyd[.]nl/bin_KyNCVEt113.bin
  • hxxp://3sixtyd[.]nl/bin_qvhDx81.bin
  • hxxp://lansol[.]com/shaq_/babaC_ZVbkF201.bin
  • hxxps://401kforce[.]com/myspecailbin_frFgfn5.bin
  • hxxps://drive.google[.]com/uc?export=download&id=1CC0uVUY8fxeHHshjvaB-rsBabBVyNuJm
  • hxxps://drive.google[.]com/uc?export=download&id=1CC0uVUY8fxeHHshjvaB-rsBabBVyNuJm
  • hxxps://drive.google[.]com/uc?export=download&id=1PxiGxacgLs_2PRBMmPOqobz1QQAB-KCC
  • hxxps://onecallitservices.co[.]uk/gumabelt_kZSaaDscx165.bin

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).

Distribution of Remcos RAT Disguised as Tax Invoice

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.

  • Abridgedly hypokinesis.exe
  • adv.._ref_copy_pdf.exe
  • Farmaceut.exe
  • Order#A0-22-039_A0009110234-22-036-pdf.exe
  • PO202202AG7.exe
  • Quote – Compagnie Madecasse _ RN6.exe
  • TNT_AWB_AND_INVOICE_098768.exe

Top 4 – Smoke Loader

Smoke Loader is an info-stealer / downloader malware that ranked fourth place with 11.1%. For an analysis report related to Smoke Loader, refer to the ASEC Report below.

[PDF] ASEC REPORT vol.101_Smoke Loader Learns New Tricks

The confirmed C&C server URLs are as follows.

  • rfgsdfhfghdfjdghkj[.]xyz
  • host-file-host6[.]com/
  • rgyui[.]top/dl/
  • acacaca[.]org/files/1/
  • cucumbetuturel4[.]com
  • linislominyt11[.]at
  • susuerulianita1[.]net
  • nusurionuy5ff[.]at
  • nunuslushau[.]com
  • moroitomo4[.]net
  • monsutiur4[.]com
  • ejeana.co[.]ug

Top 5 – Formbook

Formbook ranked fifth place with 9.5%.

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

  • Purchase Order Frank Manufact…….er Frank Manufactures.Pdf.exe
  • F22-0000746.pdf.exe
  • Statement (74002425).Pdf.exe
  • Automatic Deluge Pump.exe

As Formbook is injected into normal processes (one is a running explorer.exe and the other 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.gutro[.]online/ja25/
  • hxxp://www.caobatins[.]com/vcir/
  • hxxp://www.tecmos[.]xyz/d2s6/
  • hxxp://www.numu882[.]com/6hsc/
  • hxxp://www.chuvop[.]xyz/bg11/
  • hxxp://www.vast-yep[.]xyz/en15/
  • hxxp://www.numu882[.]com/6hsc/
  • hxxp://www.yourpamlano[.]xyz/sn31/
  • hxxp://www.gankotin[.]online/nt19/
  • hxxp://www.yaeting[.]online/f93z/
  • hxxp://www.keropy[.]xyz/s4s9/

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