Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 52fa230d2c46d8f9…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:28:23 Authoring application: Microsoft Excel First seen: 2021-07-13
MD5: 24b8295d5826697754e4d3f72046b634 SHA-1: 9471e676e65d842a99904cf8030dee1c02b8123a SHA-256: 52fa230d2c46d8f957347507e059a3b44e7aea8aa30892bbb49829e282a3949f
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 (XLM) macros, specifically an Auto_Open defined name, which is a known technique for executing malicious code upon opening the workbook. The critical heuristic firings confirm the presence of dangerous formula APIs within the Auto_Open macro, indicating an intent to execute arbitrary commands. No specific family could be identified, but the technique strongly suggests a downloader or initial execution stage.

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) 6641 bytes
SHA-256: 8e6e5de83119183dd8a3537a3d409f50b48c6352689a9e0432160bf436646180
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 -  yzuOGoWYg
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E172 
' 0018     21 LABEL : Cell Value, String Constant - azvXik len=0 
' 0018     27 LABEL : Cell Value, String Constant - BjTWxOQqZVDt len=0 
' 0018     24 LABEL : Cell Value, String Constant - cGIguWnMx len=0 
' 0018     26 LABEL : Cell Value, String Constant - CpcLdAkGjuE len=0 
' 0018     27 LABEL : Cell Value, String Constant - cQrQqQVRAOuA len=0 
' 0018     23 LABEL : Cell Value, String Constant - DpoVxiKk len=0 
' 0018     24 LABEL : Cell Value, String Constant - eibRigptW len=0 
' 0018     22 LABEL : Cell Value, String Constant - GHkWRbk len=0 
' 0018     23 LABEL : Cell Value, String Constant - GYnfaMkn len=0 
' 0018     24 LABEL : Cell Value, String Constant - hwBCohqZb len=0 
' 0018     25 LABEL : Cell Value, String Constant - InRxiCiqWL len=0 
' 0018     27 LABEL : Cell Value, String Constant - MDBKSLhWmHLp len=0 
' 0018     26 LABEL : Cell Value, String Constant - mupVtdsPxGJ len=0 
' 0018     22 LABEL : Cell Value, String Constant - OkirnQE len=0 
' 0018     27 LABEL : Cell Value, String Constant - OVRSviSgCZfE len=0 
' 0018     24 LABEL : Cell Value, String Constant - rnbBvYjqe len=0 
' 0018     24 LABEL : Cell Value, String Constant - Sfygqxawd len=0 
' 0018     22 LABEL : Cell Value, String Constant - TfbETzD len=0 
' 0018     21 LABEL : Cell Value, String Constant - wOldHz len=0 
' 0018     27 LABEL : Cell Value, String Constant - zozRalXZgEkI 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 Const
... (truncated)

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