Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 549634a95c69c79d…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:41:28 Authoring application: Microsoft Excel First seen: 2021-10-01
MD5: aadab1b3432e52ff81993735f4c75543 SHA-1: ec6e253e9088c124a80d6cd6d17fa06021a859b5 SHA-256: 549634a95c69c79db597f32ce48e4f695f2f6f1ef550f280d0f4986744a7fe4d
140 Risk Score

Malware Insights

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

The file is an Excel macro-enabled document containing Excel 4.0 (XLM) macros. Critical heuristics indicate the presence of an Auto_Open function, which is a common technique for executing malicious code upon opening the document. The macro sheet also contains dangerous formula APIs, specifically the RUN function, suggesting it's designed to launch an executable or script.

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) 6661 bytes
SHA-256: 649768c07f5d1af455741c96adda1c4c1a0dc4daaa13612b81bdf30416311309
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 -  vwQnhseCrxI
' 0018     27 LABEL : Cell Value, String Constant - AacBjuPSZdnP len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!G142 
' 0018     22 LABEL : Cell Value, String Constant - CNvrWxw len=0 
' 0018     23 LABEL : Cell Value, String Constant - fdSZIouf len=0 
' 0018     26 LABEL : Cell Value, String Constant - FNdNzwFavMM len=0 
' 0018     20 LABEL : Cell Value, String Constant - jPxIg len=0 
' 0018     26 LABEL : Cell Value, String Constant - kkhnlPVvEJe len=0 
' 0018     20 LABEL : Cell Value, String Constant - LAzZE len=0 
' 0018     26 LABEL : Cell Value, String Constant - LffEUBbuhQe len=0 
' 0018     21 LABEL : Cell Value, String Constant - nLkzwt len=0 
' 0018     21 LABEL : Cell Value, String Constant - nRcmiZ len=0 
' 0018     20 LABEL : Cell Value, String Constant - OmVXk len=0 
' 0018     25 LABEL : Cell Value, String Constant - qeaIXEFWvJ len=0 
' 0018     27 LABEL : Cell Value, String Constant - QHkJcwgXLgQp len=0 
' 0018     20 LABEL : Cell Value, String Constant - QqOYb len=0 
' 0018     21 LABEL : Cell Value, String Constant - SMzXAZ len=0 
' 0018     26 LABEL : Cell Value, String Constant - SrjJYFrnWSa len=0 
' 0018     27 LABEL : Cell Value, String Constant - tdJRxjdsMLhI len=0 
' 0018     24 LABEL : Cell Value, String Constant - VyKPYqtaw len=0 
' 0018     20 LABEL : Cell Value, String Constant - WovVk len=0 
' 0018     26 LABEL : Cell Value, String Constant - zJefLzbGzXv 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
' 00fd 
... (truncated)

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