Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 af66d9a5f92d07d3…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:47:02 Authoring application: Microsoft Excel First seen: 2021-09-18
MD5: f4a0c712d9f70dc86f8e586273874744 SHA-1: 051b866631461587bc13b25e5da0969214d0947d SHA-256: af66d9a5f92d07d39ec4c98c80b7292ad4d86d6ea66c5c32a34186b4c12fc39f
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open entry, which is a known method for executing malicious code. The macro sheet contains a reference to 'Auto_Open', suggesting it will run automatically upon opening the workbook. This is commonly used to download and execute further stages of malware.

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) 6708 bytes
SHA-256: 6d15ebf69fa3de9324d970984ccf06ff9e871f047c3710c590a64a376454e8c6
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     16 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  GkfmZsL
' 0018     26 LABEL : Cell Value, String Constant - AmqEJkoIwVk len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I146 
' 0018     25 LABEL : Cell Value, String Constant - bOzbXAfkIF len=0 
' 0018     21 LABEL : Cell Value, String Constant - bpnKQf len=0 
' 0018     23 LABEL : Cell Value, String Constant - ccGmwCcH len=0 
' 0018     22 LABEL : Cell Value, String Constant - EbvhwSa len=0 
' 0018     24 LABEL : Cell Value, String Constant - grldMzJOU len=0 
' 0018     23 LABEL : Cell Value, String Constant - JrKLNOLw len=0 
' 0018     20 LABEL : Cell Value, String Constant - lMkPD len=0 
' 0018     25 LABEL : Cell Value, String Constant - LSZkCLnmEi len=0 
' 0018     21 LABEL : Cell Value, String Constant - mEMHXV len=0 
' 0018     24 LABEL : Cell Value, String Constant - mpRyovHGL len=0 
' 0018     23 LABEL : Cell Value, String Constant - SKpZLWHD len=0 
' 0018     20 LABEL : Cell Value, String Constant - spUjB len=0 
' 0018     21 LABEL : Cell Value, String Constant - ujsbQu len=0 
' 0018     26 LABEL : Cell Value, String Constant - vYiWRWdyruu len=0 
' 0018     21 LABEL : Cell Value, String Constant - WeOrNR len=0 
' 0018     25 LABEL : Cell Value, String Constant - XOQOlItBvE len=0 
' 0018     22 LABEL : Cell Value, String Constant - ZKgiGGe len=0 
' 0018     20 LABEL : Cell Value, String Constant - ZRhAL len=0 
' 0018     22 LABEL : Cell Value, String Constant - ZUNXuUL 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     10 LABELSST : 
... (truncated)

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