Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 8c685cf94131f28f…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:44:52 Authoring application: Microsoft Excel First seen: 2021-06-20
MD5: b288ad56c91ef0303e1c699b1c1486f8 SHA-1: 63cb3faf60c847d38aed94183ed246c95f553211 SHA-256: 8c685cf94131f28fa05e9f873ac55320b81d609baba62bc27149bb34f4c6c67a
140 Risk Score

Malware Insights

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

The file contains critical heuristics indicating 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 also contains a reference to a dangerous formula API, specifically 'RUN', suggesting it is designed to execute external commands or download payloads. No specific IOCs were extracted, but the technique strongly implies a downloader or initial execution stage.

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) 6536 bytes
SHA-256: 9188671b7a49b5fec7500e8142b69c74b6dfb850fcd51c4dad77a9a5d9f49c05
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     15 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  iYZtFY
' 0018     24 LABEL : Cell Value, String Constant - aQQguvUFC len=0 
' 0018     20 LABEL : Cell Value, String Constant - aqsIY len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C149 
' 0018     23 LABEL : Cell Value, String Constant - BACxhQeK len=0 
' 0018     24 LABEL : Cell Value, String Constant - DbkdcZhGm len=0 
' 0018     25 LABEL : Cell Value, String Constant - EhdwlVfVcG len=0 
' 0018     24 LABEL : Cell Value, String Constant - FGAyyNSaf len=0 
' 0018     27 LABEL : Cell Value, String Constant - nbxbmfOGHbFY len=0 
' 0018     22 LABEL : Cell Value, String Constant - njSevya len=0 
' 0018     27 LABEL : Cell Value, String Constant - nJwkxZlOMtAD len=0 
' 0018     26 LABEL : Cell Value, String Constant - nneBioVsOLY len=0 
' 0018     23 LABEL : Cell Value, String Constant - QpZfuxoq len=0 
' 0018     24 LABEL : Cell Value, String Constant - QZSYKxTwV len=0 
' 0018     20 LABEL : Cell Value, String Constant - RAJxi len=0 
' 0018     25 LABEL : Cell Value, String Constant - RsbxnSSVxQ len=0 
' 0018     26 LABEL : Cell Value, String Constant - SUZdMUVtvsh len=0 
' 0018     23 LABEL : Cell Value, String Constant - VEsNLpyM len=0 
' 0018     23 LABEL : Cell Value, String Constant - xhQUZgAT len=0 
' 0018     22 LABEL : Cell Value, String Constant - yaCrMzP len=0 
' 0018     23 LABEL : Cell Value, String Constant - YIdylIWw len=0 
' 0018     25 LABEL : Cell Value, String Constant - yzoDogvBYF 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
' 00
... (truncated)

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