Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 550e4a6dab4b2ab1…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:40:13 Authoring application: Microsoft Excel First seen: 2021-06-04
MD5: 96ffd0b92d45e2f85406f6c145c42aa7 SHA-1: 4b38f80fabecef88040a49e4f5f1cbdf192de577 SHA-256: 550e4a6dab4b2ab16cc7939a260afdce5d327a00403b749c828135f1875fb30b
140 Risk Score

Malware Insights

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

The file is an Excel document containing Excel 4.0 (XLM) macros. A critical heuristic identified an Auto_Open defined name, indicating that the macro will execute automatically when the workbook is opened. The presence of dangerous formula APIs like RUN suggests the macro is designed to execute arbitrary code, likely downloading and running 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) 6655 bytes
SHA-256: 36203ef788f4fbfc94fc9d67c3bc341d916ebf81754f66aa73473bd7a23c5c97
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     20 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  ZliYCGtUHgL
' 0018     25 LABEL : Cell Value, String Constant - ABlXXFNXDV len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H152 
' 0018     26 LABEL : Cell Value, String Constant - bPMbyfnieSS len=0 
' 0018     25 LABEL : Cell Value, String Constant - bUpyMGPauD len=0 
' 0018     26 LABEL : Cell Value, String Constant - EwNvSXTXVRc len=0 
' 0018     26 LABEL : Cell Value, String Constant - FLbsGXuJraR len=0 
' 0018     25 LABEL : Cell Value, String Constant - gSTmRXanGr len=0 
' 0018     21 LABEL : Cell Value, String Constant - Gtnfwv len=0 
' 0018     21 LABEL : Cell Value, String Constant - hURman len=0 
' 0018     23 LABEL : Cell Value, String Constant - ijvVBEKl len=0 
' 0018     25 LABEL : Cell Value, String Constant - JEYhOTVoWl len=0 
' 0018     23 LABEL : Cell Value, String Constant - MhKhQoqi len=0 
' 0018     24 LABEL : Cell Value, String Constant - NBIrcNwrP len=0 
' 0018     21 LABEL : Cell Value, String Constant - QUQqAd len=0 
' 0018     26 LABEL : Cell Value, String Constant - sMUJYPodsEH len=0 
' 0018     23 LABEL : Cell Value, String Constant - sOQvTXat len=0 
' 0018     21 LABEL : Cell Value, String Constant - TOZObq len=0 
' 0018     24 LABEL : Cell Value, String Constant - TQMixAyAt len=0 
' 0018     21 LABEL : Cell Value, String Constant - VmAYrO len=0 
' 0018     21 LABEL : Cell Value, String Constant - xejdOj len=0 
' 0018     23 LABEL : Cell Value, String Constant - yyIGqwuT 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
' 00f
... (truncated)

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