Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 414e6c701f976c16…

MALICIOUS

Office (OLE) / .XLSX

155.2 KB Created: 2022-01-27 11:58:35 Authoring application: Microsoft Excel
MD5: e9c990242cb7dac6f6a725280552c710 SHA-1: 077ea57840830b0a2444b46e657ddaee4f7e633a SHA-256: 414e6c701f976c16a9a0312d986f9ccad2a2be67278c118513706adec11376c4
322 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Service Execution: Visual Basic T1059.001 Command and Scripting Interpreter: PowerShell T1204.002 Malicious File Execution: User Execution

The sample contains Excel 4.0 macros, specifically an Auto_Open macro, which is a critical finding. This macro is configured to execute a command using mshta.exe, which in turn downloads a file from a provided URL. The ClamAV detection and heuristic firings strongly indicate this is an Emotet downloader variant. The macro directly calls dangerous formula APIs like RUN, and the presence of mshta.exe in the document text further supports the execution path.

Heuristics 8

  • Excel 4.0 Auto_Open defined name critical OLE_XLM_AUTOOPEN_DEFINEDNAME
    oletools recovered an Auto_Open / Auto_Close entry from an Excel 4.0 macro sheet. The raw BIFF name can be tokenized or partially opaque to byte-string checks, but the recovered macro listing confirms the workbook has an XLM auto-execution entry.
  • XLM Auto_Open with dangerous formula APIs critical OLE_XLM_DANGEROUS_FN
    Excel 4.0 macro sheet contains an Auto_Open / Auto_Close entry and dangerous XLM formula APIs that can invoke programs, write files, or transfer control without VBA.
  • ClamAV: Xls.Downloader.Emotet-a5251d1d2d6d3726-9951018-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-a5251d1d2d6d3726-9951018-0
  • Reference to mshta.exe high SC_STR_MSHTA
    Reference to mshta.exe
  • LOLBin token sequence in document text high SE_LOLBIN_RUN_COMMAND
    Extracted document text contains a Windows script/execution tool name (PowerShell, mshta, cmd, rundll32, regsvr32, …) within 220 characters of a dangerous flag, command verb, or URL. This is a visible 'run this' instruction in HTML/PDF/RTF lure bodies, or — in macro-laden Office files — the macro's own string-pool entries appearing adjacent in extracted text.
  • Suspicious extracted artifact high EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Excel 4.0 (XLM) macro sheet present medium OLE_XLM_AUTOOPEN
    Workbook contains an Excel 4.0 macro sheet sub-stream — XLM is rarely seen in modern legitimate workbooks and was a major Office malware vector during 2020-2022.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://91.240.118.168/zqqw/zaas/fe.htmlB
    • http://91.240.118.168/zqqw/zaas/fe.html

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
e8a01a22c7557f125914eb9c24c0c453abc47445220644b213e0fed4e678b8cf
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3733 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 1 shell/COM execution token(s). Carved macro source contains an auto-exec entry point and execution/download terms.