Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 0c1a93e375b43723…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:41:23 Authoring application: Microsoft Excel First seen: 2021-09-27
MD5: 82df089b21b5eb3fa6374323730d6a37 SHA-1: d41e58d0c2e98925a9aa340fdc560157b5c64091 SHA-256: 0c1a93e375b43723290e870121f1931370dfff6b8aa0b5381bcedd54f3983bf8
140 Risk Score

Malware Insights

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

The sample is an Excel file containing Excel 4.0 (XLM) macros. Critical heuristics indicate the presence of an Auto_Open defined name and the use of dangerous formula APIs, specifically 'RUN'. This strongly suggests the macro is intended to execute a command or script upon opening the document, likely 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) 6878 bytes
SHA-256: 57b704f5977483df4ccddf8494893bcc2adfae9440b6d3ffc9c023766239d32a
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 -  lSEgnVpza
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I136 
' 0018     21 LABEL : Cell Value, String Constant - cNjeLn len=0 
' 0018     26 LABEL : Cell Value, String Constant - cnsDNCXjsqj len=0 
' 0018     25 LABEL : Cell Value, String Constant - EuYJSeNgAT len=0 
' 0018     25 LABEL : Cell Value, String Constant - GglQWlQkAF len=0 
' 0018     23 LABEL : Cell Value, String Constant - hMxgpSUV len=0 
' 0018     20 LABEL : Cell Value, String Constant - lkfNH len=0 
' 0018     24 LABEL : Cell Value, String Constant - LsfQcTLFo len=0 
' 0018     25 LABEL : Cell Value, String Constant - lYlFtKxZhY len=0 
' 0018     27 LABEL : Cell Value, String Constant - MCGCfdNXpIqK len=0 
' 0018     27 LABEL : Cell Value, String Constant - MoTLcvaLmwPf len=0 
' 0018     26 LABEL : Cell Value, String Constant - MUPRECIPzQe len=0 
' 0018     23 LABEL : Cell Value, String Constant - SwhpzUFb len=0 
' 0018     20 LABEL : Cell Value, String Constant - uRwaK len=0 
' 0018     26 LABEL : Cell Value, String Constant - uyivIwWGuwX len=0 
' 0018     27 LABEL : Cell Value, String Constant - UZtYkrIqTONK len=0 
' 0018     20 LABEL : Cell Value, String Constant - VbEjy len=0 
' 0018     20 LABEL : Cell Value, String Constant - vstVY len=0 
' 0018     22 LABEL : Cell Value, String Constant - VxcGDmY len=0 
' 0018     21 LABEL : Cell Value, String Constant - wxaohz len=0 
' 0018     27 LABEL : Cell Value, String Constant - xemTiSYmQgzI 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
' 
... (truncated)

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