Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 a6dc5a86bb0fbd7c…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:42:32 Authoring application: Microsoft Excel First seen: 2021-07-10
MD5: 4e46ecaf4289847d64b7faad00a8d944 SHA-1: 135115d1bd2980f1d43bb8332a30e26eb2dfe109 SHA-256: a6dc5a86bb0fbd7c44d2da59465d303467922e98738f20354994464ed43b1888
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-enabled workbook containing an Auto_Open macro. This macro is flagged as dangerous due to its use of the RUN function, indicating it's designed to execute arbitrary code. The presence of the Auto_Open entry and the use of the RUN function strongly suggest the intent is to download and execute 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) 6511 bytes
SHA-256: c66790ea04c32499fa6486680bcfdd556560bac8c6a0f4ee4d8878d63db3bf52
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     17 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  cLKQRIcH
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E136 
' 0018     20 LABEL : Cell Value, String Constant - bLItB len=0 
' 0018     25 LABEL : Cell Value, String Constant - bZTHIQCrJi len=0 
' 0018     21 LABEL : Cell Value, String Constant - cqXdxB len=0 
' 0018     21 LABEL : Cell Value, String Constant - ddUFCQ len=0 
' 0018     21 LABEL : Cell Value, String Constant - GcTwJs len=0 
' 0018     23 LABEL : Cell Value, String Constant - GEoqjQgr len=0 
' 0018     27 LABEL : Cell Value, String Constant - HbXcRoAcybEv len=0 
' 0018     26 LABEL : Cell Value, String Constant - ILkkenFqIAM len=0 
' 0018     23 LABEL : Cell Value, String Constant - iRDZIWrJ len=0 
' 0018     27 LABEL : Cell Value, String Constant - jAPTzhQUjeAm len=0 
' 0018     25 LABEL : Cell Value, String Constant - mgMXABtrsU len=0 
' 0018     20 LABEL : Cell Value, String Constant - ORGcs len=0 
' 0018     25 LABEL : Cell Value, String Constant - PzBmIJlcKP len=0 
' 0018     25 LABEL : Cell Value, String Constant - shTTfUDRDM len=0 
' 0018     21 LABEL : Cell Value, String Constant - ThKOJv len=0 
' 0018     20 LABEL : Cell Value, String Constant - uYJZM len=0 
' 0018     27 LABEL : Cell Value, String Constant - VujxyoJebvDw len=0 
' 0018     21 LABEL : Cell Value, String Constant - vZtFlD len=0 
' 0018     23 LABEL : Cell Value, String Constant - wTeaMZjW len=0 
' 0018     26 LABEL : Cell Value, String Constant - WZuhLWQOgOR 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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