Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 1d801298e555fc14…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:45:28 Authoring application: Microsoft Excel First seen: 2021-10-23
MD5: f8bd3c506549bc43389dbf7d25052497 SHA-1: d52c12cc2ef1a231ec21a004290686b2e13d935d SHA-256: 1d801298e555fc149056e09cf4d82fcd013e48515b5631f00c16af904ea81f76
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. The critical heuristics indicate the presence of an Auto_Open defined name and the use of dangerous formula APIs, specifically the RUN function. This strongly suggests the macro is designed to execute arbitrary code upon opening the document, likely to download and run 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) 6597 bytes
SHA-256: 41b75da884fd9a844483f304f8583a9cc1e8b3b45f121b77d2177c1bf1eb2b63
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 -  ZjpiOTxCV
' 0018     27 LABEL : Cell Value, String Constant - aPBBWfevTrzA len=0 
' 0018     26 LABEL : Cell Value, String Constant - ASsPXqUtGKR len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E159 
' 0018     23 LABEL : Cell Value, String Constant - AZcuvWJq len=0 
' 0018     22 LABEL : Cell Value, String Constant - cjOGAnH len=0 
' 0018     26 LABEL : Cell Value, String Constant - dtueEIuoDUZ len=0 
' 0018     20 LABEL : Cell Value, String Constant - edyct len=0 
' 0018     26 LABEL : Cell Value, String Constant - enrjloqylkv len=0 
' 0018     22 LABEL : Cell Value, String Constant - hKyoVou len=0 
' 0018     25 LABEL : Cell Value, String Constant - hpzzsOAOLO len=0 
' 0018     26 LABEL : Cell Value, String Constant - HxzzVNNkxFR len=0 
' 0018     23 LABEL : Cell Value, String Constant - iPtIlDax len=0 
' 0018     22 LABEL : Cell Value, String Constant - lCsXVwJ len=0 
' 0018     27 LABEL : Cell Value, String Constant - LkIqhLboRHPp len=0 
' 0018     27 LABEL : Cell Value, String Constant - MkncTaejAaiz len=0 
' 0018     24 LABEL : Cell Value, String Constant - szbArjTIl len=0 
' 0018     20 LABEL : Cell Value, String Constant - xQIGZ len=0 
' 0018     24 LABEL : Cell Value, String Constant - XvlkOXZue len=0 
' 0018     20 LABEL : Cell Value, String Constant - xYuFL len=0 
' 0018     27 LABEL : Cell Value, String Constant - XzdeucLloxSj len=0 
' 0018     25 LABEL : Cell Value, String Constant - ZkiUVXBWui 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/
... (truncated)

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