Lumma Stealer infection with Sectop RAT (ArechClient2)

    Published: 2026-04-17. Last Updated: 2026-04-17 00:30:27 UTC
    by Brad Duncan (Version: 1)
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    Introduction

    This diary provides indicators from a Lumma Stealer infection that was followed by Sectop RAT (ArechClient2). I searched for cracked versions of popular copyright-protected software, and I downloaded the initial malware after following the results of one such search. This is a common distribution technique for various families of malware, and I often find Lumma Stealer this way.

    In this case, the initial malware for Lumma Stealer was delivered as a password-protected 7-zip archive. The extracted malware is an inflated Windows executable (EXE) file at 806 MB. The EXE is padded with null-bytes (0x00), a technical which increases the EXE size while allowing the compressed archive file to be much smaller. The password-protected archive and inflated EXE file are designed to avoid detection.

    Images from the infection


    Shown above: Example of a page with instructions to download the initial malware file.


    Shown above: Traffic from the infection filtered in Wireshark.


    Shown above: Sectop RAT persistent on an infected Windows host.

    Indicators of Compromise

    Example of download link from the site advertising cracked versions of copyright-protected software:

    hxxps[:]//incolorand[.]com/how-visual-patch-enhances-ui-consistency-across-releases/?utm_source={CID}&utm_term=Adobe%20Premiere%20Pro%20(2026)%20Full%20v26.0.2%20Espa%C3%B1ol%20[Mega]&utm_content={SUBID1}&utm_medium={SUBID2}

    Example of URL for page with the file download instructions:

    hxxps[:]//mega-nz.goldeneagletransport[.]com/Adobe_Premiere_Pro_%282026%29_Full_v26.0.2_Espa%C3%B1ol_%5BMega%5D.zip?c=ABUZ4WkRgQUA_YUCAFVTFwASAAAAAACh&s=360721

    Example of URL for file download from site above site impersonating MEGA:

    hxxps[:]//arch.primedatahost3[.]cfd/auth/media/JvWcFd5vUoYTrImvtWQAASTh/Adobe_Premiere_Pro_(2026)_Full_v26.0.2_Espa%C3%B1ol_%5BMega%5D.zip

    Downloaded file:

    Extracted malware:

    • SHA256 hash: 4849f76dafbef516df91fecfc23a72afffaf77ade51f805eae5ad552bed88923
    • File size: 806,127,604 bytes
    • File name: appFile.exe
    • File type: PE32 executable (GUI) Intel 80386, for MS Windows
    • File description: Inflated Windows EXE file for Lumma Stealer, padded with null-bytes

    Deflated malware:

    Lumma Stealer command and control (C2) domains from Triage sandbox analysis:

    • cankgmr[.]cyou
    • carytui[.]vu
    • decrnoj[.]club
    • genugsq[.]best
    • longmbx[.]click
    • mushxhb[.]best
    • pomflgf[.]vu
    • strikql[.]shop
    • ulmudhw[.]shop

    Follow-up malware:

    Example of Sectop RAT C2 traffic from an infected Windows host:

    • hxxp[:]//91.92.241[.]102:9000/wmglb
    • hxxp[:]//91.92.241[.]102:9000/wbinjget?q=66B553A8B94CE37C16F4EBC863D51FCC
    • tcp[:]//91.92.241[.]102:443/ - encoded or otherwise encrypted traffic (not HTTPS/TLS)

    ---
    Bradley Duncan
    brad [at] malware-traffic-analysis.net

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