Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 3f23af8a47588e0a…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:40:40 Authoring application: Microsoft Excel First seen: 2021-10-07
MD5: db7cd2128e53e5cd885300299a95ed3d SHA-1: a93444f0385f60f8243edb7bbb090094ed3b8157 SHA-256: 3f23af8a47588e0a34b84a6198cfb99a30dbadc6c306a011da83a0209c1c2918
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known technique for executing malicious code upon opening the document. The presence of dangerous formula APIs like RUN further indicates malicious intent. The macro sheet itself contains obfuscated strings and potentially executable content.

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) 6626 bytes
SHA-256: fdae5bba3b383a7675aad928d3ec30cd5f92271b0c866aaebacbcc5e65ed48e3
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     19 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  JaswGuuhpb
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D185 
' 0018     23 LABEL : Cell Value, String Constant - CqlrwpPI len=0 
' 0018     25 LABEL : Cell Value, String Constant - HBzOGzMGkB len=0 
' 0018     22 LABEL : Cell Value, String Constant - hHqYYZm len=0 
' 0018     21 LABEL : Cell Value, String Constant - hJPVcs len=0 
' 0018     27 LABEL : Cell Value, String Constant - HlcqCxtaoBHe len=0 
' 0018     24 LABEL : Cell Value, String Constant - JHWuqKQvV len=0 
' 0018     27 LABEL : Cell Value, String Constant - JZzAiPoNAPve len=0 
' 0018     24 LABEL : Cell Value, String Constant - KamDTazhg len=0 
' 0018     27 LABEL : Cell Value, String Constant - kNwoErjWjsHj len=0 
' 0018     20 LABEL : Cell Value, String Constant - mPdQr len=0 
' 0018     27 LABEL : Cell Value, String Constant - oBpuUGfTPeOX len=0 
' 0018     24 LABEL : Cell Value, String Constant - ObqdLWUsD len=0 
' 0018     24 LABEL : Cell Value, String Constant - pniGAljgi len=0 
' 0018     21 LABEL : Cell Value, String Constant - PqVWLk len=0 
' 0018     24 LABEL : Cell Value, String Constant - qNrgjrifS len=0 
' 0018     21 LABEL : Cell Value, String Constant - RcZkex len=0 
' 0018     24 LABEL : Cell Value, String Constant - seDTAdIkm len=0 
' 0018     27 LABEL : Cell Value, String Constant - SsgmoCGhbQWT len=0 
' 0018     21 LABEL : Cell Value, String Constant - XfyzBV len=0 
' 0018     21 LABEL : Cell Value, String Constant - xHYXvj 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
' 
... (truncated)

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