Malicious Office (OLE) / .XLSX — malware analysis report

Static analysis result for SHA-256 d49e9025b35f9a34…

MALICIOUS

Office (OLE) / .XLSX

75.7 KB Created: 2022-01-26 21:52:19 Authoring application: Microsoft Excel
MD5: 87c7ea3fce1ae91a1fdaafd64d788191 SHA-1: 696136e9d7a90b1de2cee39cad831a1ce4e35ca2 SHA-256: d49e9025b35f9a342a86473f059bec35c9c22d4f41619d3e80cc151e78ed1514
322 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open macro that is configured to execute a command. This command uses mshta to download and execute a script from the URL http://91.240.118.168/zzx/ccv/fe.html. The ClamAV detection and heuristic firings strongly indicate this is a downloader for a malicious payload, likely Emotet.

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.EmotetRed02220-9938633-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.EmotetRed02220-9938633-0
  • 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/zzx/ccv/fe.htmlB
    • http://91.240.118.168/zzx/ccv/fe.html

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
ae04d5c104f21141f430aad243ecbad709822bd8efcfd8c6a83945c0ae8dd42a
xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 3673 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.