Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 74fd5b5a996c61bb…

MALICIOUS

Office (OLE) / .XLSX

44.5 KB Created: 2022-01-26 14:19:06 Authoring application: Microsoft Excel
MD5: 5f8922d383773afa3eab5c66d0c5f1c4 SHA-1: 845aa45f48462e9a2b8a351364fc02e814d18e0f SHA-256: 74fd5b5a996c61bbc0b92796792e3128792e94d1b0b3134ac6fb443f562c4216
322 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample contains an Excel 4.0 macro that automatically executes upon opening. This macro uses the 'EXEC' function to run a command that launches 'mshta.exe' with a URL, indicating an attempt to download and execute a second-stage payload. The ClamAV detection name 'Doc.Downloader.Emotet01220-9937698-0' strongly suggests the Emotet family.

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: Doc.Downloader.Emotet01220-9937698-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Emotet01220-9937698-0
  • 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/fe/f.htmlB
    • http://91.240.118.168/fe/f.html

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
1496b5efc0849ea9e0695ef96c66819bec865a2ce110a32e705833c9ed3fc17b
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 1149 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.