Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 5bb21ad158ffd8d5…

MALICIOUS

Office (OLE) / .XLSX

89.7 KB Created: 2022-01-27 23:33:44 Authoring application: Microsoft Excel
MD5: 8ae8dc1de8bf02c01b7f6dae0ffe44ac SHA-1: 5117eb414eb8517d702c06df86c72f3327c0543a SHA-256: 5bb21ad158ffd8d5bdb9bc7a065cc1dfcee95f0edc94ef18997842a9b5f1c538
322 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1059.005 Visual Basic T1203 Exploitation for Client Execution

The sample contains Excel 4.0 macros, specifically an Auto_Open macro, which is designed to execute a command. This command uses mshta to download and execute a script from the URL http://91.240.118.172/ee/ss/se.html. This behavior is characteristic of downloader malware like Emotet, which often uses macro-enabled documents to fetch and run further malicious payloads.

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.EmotetRed02220-9938645-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.EmotetRed02220-9938645-0
  • 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://91.240.118.172/ee/ss/se.html

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
712daaadef5bb5a097700650c710c5cfa82b295835e03515a82f90167f9f4c8e
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 540 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.