Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 8390b3d5630a1129…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-25 10:43:53 Authoring application: Microsoft Excel First seen: 2021-10-23
MD5: 94cb37da79f79c498f21b800935eadf6 SHA-1: 051162bf7504c6e03d3316ea3bae286c62af67d0 SHA-256: 8390b3d5630a11291c698d298522df363e1524fb554baadf946bc17b2a3a9521
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 workbook. The critical heuristic firings indicate the presence of dangerous formula APIs, including the RUN function, suggesting the macro is designed to execute a payload. No specific family could be identified, but the technique is common for initial execution.

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: 634f4b198e3a6c190212cc78220688975107174a7c83d0fe2111ed23704d2fee
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     14 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  gOvwf
' 0018     26 LABEL : Cell Value, String Constant - AAWcevOkEEj len=0 
' 0018     25 LABEL : Cell Value, String Constant - aFARCMrcxv len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G174 
' 0018     24 LABEL : Cell Value, String Constant - AxFiWzyiI len=0 
' 0018     22 LABEL : Cell Value, String Constant - bfcJlxu len=0 
' 0018     22 LABEL : Cell Value, String Constant - BvmpWjh len=0 
' 0018     25 LABEL : Cell Value, String Constant - FvRGnOPRVs len=0 
' 0018     24 LABEL : Cell Value, String Constant - GOkWDDwRk len=0 
' 0018     23 LABEL : Cell Value, String Constant - GtNzjVvd len=0 
' 0018     27 LABEL : Cell Value, String Constant - iaROZhCEmJse len=0 
' 0018     20 LABEL : Cell Value, String Constant - IegZl len=0 
' 0018     21 LABEL : Cell Value, String Constant - KbCHVE len=0 
' 0018     26 LABEL : Cell Value, String Constant - kbqHRBvrRKV len=0 
' 0018     27 LABEL : Cell Value, String Constant - mKPHMVUlWGwy len=0 
' 0018     26 LABEL : Cell Value, String Constant - NGMWEVdYGxl len=0 
' 0018     24 LABEL : Cell Value, String Constant - plBHDefYB len=0 
' 0018     26 LABEL : Cell Value, String Constant - pMMVXCknPLI len=0 
' 0018     24 LABEL : Cell Value, String Constant - UhmLJWSYK len=0 
' 0018     21 LABEL : Cell Value, String Constant - WkflNb len=0 
' 0018     21 LABEL : Cell Value, String Constant - XTKTlu len=0 
' 0018     27 LABEL : Cell Value, String Constant - zBtRQBcvHNIN 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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