Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b6d410d59a9c773c…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:37:48 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: e1b2286d0ecac6857585756f4cd7b57f SHA-1: 0093a5f652d1d3e86d9a4a91b6ad7bcee51706ef SHA-256: b6d410d59a9c773cc0cff87f01ccfd0239381ecaa6606e99094a9e17868ee632
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry, which is a common technique for executing malicious code upon opening the document. The macro sheet's name, 'zsGxrwytoljt', is included as a potential indicator. The Auto_Open function is likely used to download and execute a second-stage payload, aligning with spearphishing attachment tactics.

Heuristics 3

  • 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.
  • 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 xlm-macro oletools.olevba.extract_all_macros (XLM macro listing) 6926 bytes
SHA-256: ecf40f3b62bd6afd2b7d654b7448a50d9616bb7150eee346165b56b1c9c3feff
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     20 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  zsGXrwytoLJ
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!B151 
' 0018     20 LABEL : Cell Value, String Constant - CSIkB len=0 
' 0018     26 LABEL : Cell Value, String Constant - CtJsyTXDSpM len=0 
' 0018     25 LABEL : Cell Value, String Constant - CzATlRnNSg len=0 
' 0018     27 LABEL : Cell Value, String Constant - eXHsaZLlHoel len=0 
' 0018     22 LABEL : Cell Value, String Constant - HfwBSzY len=0 
' 0018     26 LABEL : Cell Value, String Constant - hPEmabMNnwE len=0 
' 0018     25 LABEL : Cell Value, String Constant - HwIOpokWHj len=0 
' 0018     22 LABEL : Cell Value, String Constant - IWTbdku len=0 
' 0018     26 LABEL : Cell Value, String Constant - kWTcjpuVWue len=0 
' 0018     27 LABEL : Cell Value, String Constant - MTUVBcdthxcG len=0 
' 0018     26 LABEL : Cell Value, String Constant - NcymTMlaLzg len=0 
' 0018     23 LABEL : Cell Value, String Constant - OiLdYOiT len=0 
' 0018     26 LABEL : Cell Value, String Constant - OSMjDJRsgWM len=0 
' 0018     27 LABEL : Cell Value, String Constant - SwrdljSfAerE len=0 
' 0018     22 LABEL : Cell Value, String Constant - uHTRzVT len=0 
' 0018     25 LABEL : Cell Value, String Constant - wdVpkZKgWr len=0 
' 0018     26 LABEL : Cell Value, String Constant - WFhfANpSjqS len=0 
' 0018     24 LABEL : Cell Value, String Constant - YmyjtnoPU len=0 
' 0018     21 LABEL : Cell Value, String Constant - yoWZVj len=0 
' 0018     23 LABEL : Cell Value, String Constant - YPPjTLSp len=0 
' 002a      2 PRINTHEADERS : Print Row/Column Labels
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String Constant/ SST
' 00fd     10 LABELSST : Cell Value, String 
... (truncated)

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