Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 cdb51a76fb4bb90f…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:31:45 Authoring application: Microsoft Excel First seen: 2021-07-07
MD5: be9f40b1f96ed338307a3b96a46962d3 SHA-1: 7cf1e823705d30f19f5f66b2feb4090496856b17 SHA-256: cdb51a76fb4bb90fd039685bfa69233113855162e16ae5c5740bb9b2d4e7c63a
140 Risk Score

Malware Insights

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

The file contains critical heuristic firings indicating the presence of Excel 4.0 (XLM) macros, specifically an Auto_Open defined name. This suggests the macro is designed to execute automatically upon opening the workbook. The presence of dangerous formula APIs like RUN in the XLM macros points towards the execution of arbitrary commands, likely for downloading and executing a secondary payload. No specific family could be identified.

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) 6370 bytes
SHA-256: a082f16b7f8f04c66581592fd1a0312b408cd4d78d955d80b9d45744e846069d
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     13 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  meFr
' 0018     25 LABEL : Cell Value, String Constant - akUagHLPIA len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!H137 
' 0018     26 LABEL : Cell Value, String Constant - esDUGcXgcch len=0 
' 0018     23 LABEL : Cell Value, String Constant - fTFAIESp len=0 
' 0018     25 LABEL : Cell Value, String Constant - HDOcSjOoso len=0 
' 0018     22 LABEL : Cell Value, String Constant - HolUeZg len=0 
' 0018     25 LABEL : Cell Value, String Constant - hYNLdoDSYD len=0 
' 0018     23 LABEL : Cell Value, String Constant - jvZaNDBo len=0 
' 0018     23 LABEL : Cell Value, String Constant - kAMpGagQ len=0 
' 0018     21 LABEL : Cell Value, String Constant - Mccbcq len=0 
' 0018     21 LABEL : Cell Value, String Constant - mJKFzh len=0 
' 0018     20 LABEL : Cell Value, String Constant - NetFY len=0 
' 0018     21 LABEL : Cell Value, String Constant - nhJxxx len=0 
' 0018     27 LABEL : Cell Value, String Constant - PTqtvLaRPQFW len=0 
' 0018     27 LABEL : Cell Value, String Constant - pZedojEIOzJs len=0 
' 0018     20 LABEL : Cell Value, String Constant - RpMAG len=0 
' 0018     20 LABEL : Cell Value, String Constant - UPyOX len=0 
' 0018     24 LABEL : Cell Value, String Constant - UuUKnKUvj len=0 
' 0018     23 LABEL : Cell Value, String Constant - wesMvdNr len=0 
' 0018     25 LABEL : Cell Value, String Constant - xEaYbTKhko len=0 
' 0018     20 LABEL : Cell Value, String Constant - XQbxs 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     10 LABELSS
... (truncated)

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