Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 c715718183bb925e…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:43:59 Authoring application: Microsoft Excel First seen: 2021-10-02
MD5: 6f40f2ba0b65581039db957cc5098288 SHA-1: 5f683e8a5b1a15beb978f444e7c367c136eccf8c SHA-256: c715718183bb925e6ccbeabc6ef5d03f02d3adefc683d087507d734b97ce846f
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. The presence of an 'Auto_Open' defined name indicates that the macro will execute automatically when the workbook is opened. Heuristics indicate the use of dangerous formula APIs within the macro, suggesting it is designed to perform malicious actions, such as downloading and executing 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) 6612 bytes
SHA-256: b5653071104ed2621082de6c1634c41bb93a45ae42ff44c515aaecb9e0d90c24
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 -  vvucEPjTD
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I190 
' 0018     25 LABEL : Cell Value, String Constant - BrsZmTZKCw len=0 
' 0018     23 LABEL : Cell Value, String Constant - CeYSkpiz len=0 
' 0018     23 LABEL : Cell Value, String Constant - clgyFLYH len=0 
' 0018     27 LABEL : Cell Value, String Constant - dTmKqWpVfKTt len=0 
' 0018     22 LABEL : Cell Value, String Constant - IljQVrm len=0 
' 0018     22 LABEL : Cell Value, String Constant - ipseKLH len=0 
' 0018     27 LABEL : Cell Value, String Constant - lUIlHZYWazmg len=0 
' 0018     27 LABEL : Cell Value, String Constant - NoNZVtccSirg len=0 
' 0018     22 LABEL : Cell Value, String Constant - OXnnabn len=0 
' 0018     25 LABEL : Cell Value, String Constant - pbsrBhyBHu len=0 
' 0018     20 LABEL : Cell Value, String Constant - qsJoJ len=0 
' 0018     24 LABEL : Cell Value, String Constant - sveRbwwex len=0 
' 0018     24 LABEL : Cell Value, String Constant - TbTnjFOPo len=0 
' 0018     23 LABEL : Cell Value, String Constant - TqGNaxpX len=0 
' 0018     24 LABEL : Cell Value, String Constant - UbeULHdAY len=0 
' 0018     25 LABEL : Cell Value, String Constant - UoGawOvOLT len=0 
' 0018     20 LABEL : Cell Value, String Constant - VpppE len=0 
' 0018     26 LABEL : Cell Value, String Constant - woUElEpqPyY len=0 
' 0018     27 LABEL : Cell Value, String Constant - XFAVxMKAaaBy len=0 
' 0018     24 LABEL : Cell Value, String Constant - xJwJfeBCC 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/ S
... (truncated)

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