Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 abd3c6354084e9d3…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:45:19 Authoring application: Microsoft Excel First seen: 2020-12-25
MD5: 8906386115cf1a0bdc5192d9548a34ed SHA-1: 8a83e249ffd75ce88657d37a957ac04f1eba8b7e SHA-256: abd3c6354084e9d3f079ff981556bdd85dedcc571849c2d4d4802f19c2c0dea8
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 macros, indicated by the OLE_XLM_AUTOOPEN and OLE_XLM_DANGEROUS_FN heuristic firings. The presence of an Auto_Open defined name suggests that the macro will execute automatically upon opening the workbook. The dangerous formula APIs used, specifically 'RUN', strongly indicate that the macro is designed 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) 6691 bytes
SHA-256: 700a21c768e92fa9a0e710f13bd392775858c8be97384329e1fce9a18a35afae
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 -  BxsoXlCYWRk
' 0018     22 LABEL : Cell Value, String Constant - akSXXAP len=0 
' 0018     23 LABEL : Cell Value, String Constant - aPLNzDtp len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H172 
' 0018     21 LABEL : Cell Value, String Constant - ElXrEU len=0 
' 0018     23 LABEL : Cell Value, String Constant - eNNvjQyz len=0 
' 0018     27 LABEL : Cell Value, String Constant - gQQOWXFlzORk len=0 
' 0018     24 LABEL : Cell Value, String Constant - ILSCGyEek len=0 
' 0018     24 LABEL : Cell Value, String Constant - JVSlXdSNu len=0 
' 0018     22 LABEL : Cell Value, String Constant - kUXCFhe len=0 
' 0018     27 LABEL : Cell Value, String Constant - NSVmzOSnOqEv len=0 
' 0018     21 LABEL : Cell Value, String Constant - pbubft len=0 
' 0018     21 LABEL : Cell Value, String Constant - PHwHMx len=0 
' 0018     24 LABEL : Cell Value, String Constant - PTguEzocL len=0 
' 0018     21 LABEL : Cell Value, String Constant - qiNFKw len=0 
' 0018     21 LABEL : Cell Value, String Constant - qqkAyf len=0 
' 0018     24 LABEL : Cell Value, String Constant - RDwDBclzZ len=0 
' 0018     23 LABEL : Cell Value, String Constant - WvIhjiFW len=0 
' 0018     25 LABEL : Cell Value, String Constant - WWCALnTiHD len=0 
' 0018     26 LABEL : Cell Value, String Constant - xiUlPnLKOnS len=0 
' 0018     22 LABEL : Cell Value, String Constant - ZtWzwOZ len=0 
' 0018     22 LABEL : Cell Value, String Constant - ZugOswb 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     1
... (truncated)

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