Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 6b27adc47458d59f…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:38:43 Authoring application: Microsoft Excel First seen: 2021-07-10
MD5: 7f161984dceeb92798af73b089c05a06 SHA-1: 38056c0e947d2121666658756d06d7c41cca8806 SHA-256: 6b27adc47458d59f5cf39cfda5bc7e239d1d548c298fa66f35356469993a8969
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 (XLM) macros, indicated by the OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN heuristics. The presence of an Auto_Open defined name suggests that the macro is intended to run automatically when the workbook is opened. The dangerous formula APIs used in the macro indicate it's designed for malicious execution, likely to download and execute a second-stage payload.

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) 6792 bytes
SHA-256: 392ef05c0249055600e4a9e10e8b654bbf793b6ce73ee271f7988b09fb34802f
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     18 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  AuLiOIAuM
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!A174 
' 0018     24 LABEL : Cell Value, String Constant - dIYhNTyJQ len=0 
' 0018     25 LABEL : Cell Value, String Constant - eEpviHYumE len=0 
' 0018     20 LABEL : Cell Value, String Constant - FcOJN len=0 
' 0018     23 LABEL : Cell Value, String Constant - gwsfUplp len=0 
' 0018     22 LABEL : Cell Value, String Constant - htaAnxk len=0 
' 0018     21 LABEL : Cell Value, String Constant - Kvbuyb len=0 
' 0018     23 LABEL : Cell Value, String Constant - LfhFPxuP len=0 
' 0018     24 LABEL : Cell Value, String Constant - lvotKsdcW len=0 
' 0018     23 LABEL : Cell Value, String Constant - mLuAvaVk len=0 
' 0018     26 LABEL : Cell Value, String Constant - OQXRCjarvVj len=0 
' 0018     20 LABEL : Cell Value, String Constant - pfusW len=0 
' 0018     23 LABEL : Cell Value, String Constant - sUMdkkie len=0 
' 0018     22 LABEL : Cell Value, String Constant - TMWeQSt len=0 
' 0018     25 LABEL : Cell Value, String Constant - UlrhTabrWe len=0 
' 0018     25 LABEL : Cell Value, String Constant - UwpYsHhzfV len=0 
' 0018     26 LABEL : Cell Value, String Constant - vjPvkpewXMt len=0 
' 0018     23 LABEL : Cell Value, String Constant - vWmPwzqY len=0 
' 0018     24 LABEL : Cell Value, String Constant - xASlcKiIG len=0 
' 0018     25 LABEL : Cell Value, String Constant - xCVseJyUPV len=0 
' 0018     24 LABEL : Cell Value, String Constant - zXJKExPhf 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   
... (truncated)

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