Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c84e891b9cf7df78…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:40:58 Authoring application: Microsoft Excel First seen: 2021-07-07
MD5: b324f953d67761ad15e7e1aff7fbd275 SHA-1: db477581096c28212a027f068a86e5d2691e1e13 SHA-256: c84e891b9cf7df78d5eff76bf7ba97371650a0a167ea516b6120487769f8d3bd
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry, which is a common method for executing malicious code upon opening the document. The macro sheet contains obfuscated strings and potentially dangerous formula APIs, suggesting an intent to download and execute a second-stage payload. No specific family could be identified due to the generic nature of the macro execution.

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) 6705 bytes
SHA-256: 902ca22823ee828a9bc3e9f9351558af748764f91d764e0d3255d32a67110c3c
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     16 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  JxsTXbi
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G176 
' 0018     23 LABEL : Cell Value, String Constant - bbCWZzdb len=0 
' 0018     20 LABEL : Cell Value, String Constant - FBKJl len=0 
' 0018     23 LABEL : Cell Value, String Constant - FHKdESZE len=0 
' 0018     25 LABEL : Cell Value, String Constant - FyERimSPyf len=0 
' 0018     20 LABEL : Cell Value, String Constant - HAHsl len=0 
' 0018     22 LABEL : Cell Value, String Constant - IRkKigX len=0 
' 0018     26 LABEL : Cell Value, String Constant - KqtfXDGOFoW len=0 
' 0018     27 LABEL : Cell Value, String Constant - LcrjkAkETgmY len=0 
' 0018     24 LABEL : Cell Value, String Constant - LjsxHEhzp len=0 
' 0018     20 LABEL : Cell Value, String Constant - Lvpgv len=0 
' 0018     21 LABEL : Cell Value, String Constant - MKDYue len=0 
' 0018     21 LABEL : Cell Value, String Constant - nOSpPM len=0 
' 0018     23 LABEL : Cell Value, String Constant - oAYEVhJD len=0 
' 0018     24 LABEL : Cell Value, String Constant - piQDfKNdc len=0 
' 0018     25 LABEL : Cell Value, String Constant - pqzcTWZQsd len=0 
' 0018     27 LABEL : Cell Value, String Constant - RdHyfltvmbXT len=0 
' 0018     22 LABEL : Cell Value, String Constant - tUSozub len=0 
' 0018     25 LABEL : Cell Value, String Constant - UPVwzEpywU len=0 
' 0018     20 LABEL : Cell Value, String Constant - XeUPh len=0 
' 0018     25 LABEL : Cell Value, String Constant - ZjpUZTvohX 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 Constant/ SST
' 00fd     10 LA
... (truncated)

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