Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b8aae3b2189c8328…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:27:37 Authoring application: Microsoft Excel First seen: 2021-06-28
MD5: 752a3b50cd640747770ed944a02437ad SHA-1: 962d85c9b85492d437b54f0261dc6e349be529c8 SHA-256: b8aae3b2189c8328a31becb0d2601e68d7f253746d99df4827bdbc630e0fe846
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, specifically an Auto_Open macro. This macro is designed to execute dangerous formulas, including the RUN function, which is highly indicative of downloading and executing a secondary payload. The presence of the Auto_Open entry and the use of dangerous functions strongly suggest malicious intent.

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) 6406 bytes
SHA-256: fee72039b4839696cf780613191964e3746667357ebd322f702dfa40a7709edf
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     13 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  sePl
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E168 
' 0018     22 LABEL : Cell Value, String Constant - BdKnxCT len=0 
' 0018     26 LABEL : Cell Value, String Constant - BkAFGtBbneO len=0 
' 0018     26 LABEL : Cell Value, String Constant - DMpsgVYnJYa len=0 
' 0018     20 LABEL : Cell Value, String Constant - EwRxV len=0 
' 0018     20 LABEL : Cell Value, String Constant - FcjEZ len=0 
' 0018     21 LABEL : Cell Value, String Constant - fxyFiS len=0 
' 0018     22 LABEL : Cell Value, String Constant - hHDNmNe len=0 
' 0018     27 LABEL : Cell Value, String Constant - kTfOBnITUdDa len=0 
' 0018     23 LABEL : Cell Value, String Constant - kwccragB len=0 
' 0018     25 LABEL : Cell Value, String Constant - lyyFstvosU len=0 
' 0018     25 LABEL : Cell Value, String Constant - MMowwoUGEY len=0 
' 0018     25 LABEL : Cell Value, String Constant - msOnUldSDe len=0 
' 0018     26 LABEL : Cell Value, String Constant - NFzFjdpkYMX len=0 
' 0018     24 LABEL : Cell Value, String Constant - nZljHwolg len=0 
' 0018     26 LABEL : Cell Value, String Constant - oEGwzkgfTjn len=0 
' 0018     24 LABEL : Cell Value, String Constant - oqXgCKjoq len=0 
' 0018     25 LABEL : Cell Value, String Constant - rUiUrfvSeg len=0 
' 0018     20 LABEL : Cell Value, String Constant - sJjtJ len=0 
' 0018     20 LABEL : Cell Value, String Constant - swoRS len=0 
' 0018     25 LABEL : Cell Value, String Constant - TmvCblfNPP 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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