Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 55bcc997c76852fe…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:33:06 Authoring application: Microsoft Excel First seen: 2021-10-11
MD5: 2647c5ccf32760f6b8da19b2f2513a91 SHA-1: b60e7b7e8f4928ac6b20b12681761b54b245a324 SHA-256: 55bcc997c76852fe7b6d623e56ce90fb81fe3c4bc5dafd8f3fa9e23bc1576eb6
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro sheet containing an Auto_Open defined name, indicating an attempt to automatically execute code upon opening. Heuristics identified the use of dangerous formula APIs, specifically referencing RUN=0, which suggests the macro is designed to execute arbitrary commands or payloads. The presence of numerous obfuscated string constants within the macro sheet further supports a malicious intent.

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) 6635 bytes
SHA-256: 7236674fb243769b8e1a98d79a92b02f637229431f08c439c8844324529ef77a
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 -  ZyhBoIzpMA
' 0018     20 LABEL : Cell Value, String Constant - AKqKp len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I176 
' 0018     26 LABEL : Cell Value, String Constant - bVVDkPcRywg len=0 
' 0018     24 LABEL : Cell Value, String Constant - fkyXQIuJZ len=0 
' 0018     21 LABEL : Cell Value, String Constant - gQrwyZ len=0 
' 0018     20 LABEL : Cell Value, String Constant - hdVDT len=0 
' 0018     21 LABEL : Cell Value, String Constant - JxcVqs len=0 
' 0018     27 LABEL : Cell Value, String Constant - LrNPqOoUAjck len=0 
' 0018     26 LABEL : Cell Value, String Constant - NZjUkHVPcWS len=0 
' 0018     20 LABEL : Cell Value, String Constant - oNGrI len=0 
' 0018     22 LABEL : Cell Value, String Constant - QFzVOFe len=0 
' 0018     20 LABEL : Cell Value, String Constant - sXFVA len=0 
' 0018     27 LABEL : Cell Value, String Constant - tVgIttkbFkiV len=0 
' 0018     23 LABEL : Cell Value, String Constant - VQxEFRpd len=0 
' 0018     24 LABEL : Cell Value, String Constant - VsdwrwVfB len=0 
' 0018     23 LABEL : Cell Value, String Constant - WNvUYBNW len=0 
' 0018     23 LABEL : Cell Value, String Constant - XfSYUBSt len=0 
' 0018     27 LABEL : Cell Value, String Constant - yaJpyldxtoCm len=0 
' 0018     26 LABEL : Cell Value, String Constant - ZduotlXVWvY len=0 
' 0018     25 LABEL : Cell Value, String Constant - ZeJtidNUib len=0 
' 0018     26 LABEL : Cell Value, String Constant - zKntuGNhWrz 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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