Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ac779f3f97a547a1…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-27 11:38:46 Authoring application: Microsoft Excel First seen: 2021-06-28
MD5: 03580b3ab53111650aa038a892a5ac04 SHA-1: cbca6a8b533b47f8eca563416d993d6e39986af3 SHA-256: ac779f3f97a547a14e8e4567c1b6bbbcd6d65f63856e9ac753a074795d3ec59e
140 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The file contains Excel 4.0 macros, specifically an Auto_Open function, which is a known method for executing malicious code. The critical heuristics indicate the presence of dangerous formula APIs within the Auto_Open macro, suggesting it's designed to run arbitrary commands. This points to a macro-based downloader, likely delivered as a spearphishing attachment, intended to fetch and execute a further 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) 6757 bytes
SHA-256: 46ea92cc54b069809a8ed4e51f63a2aebae56d9fa95afcae56a0e8f57e8fce1e
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 -  BYhEZQNf
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D147 
' 0018     27 LABEL : Cell Value, String Constant - EeNqXzMChKMx len=0 
' 0018     27 LABEL : Cell Value, String Constant - ekvZbMbPuLVY len=0 
' 0018     25 LABEL : Cell Value, String Constant - FbalpGuRlO len=0 
' 0018     21 LABEL : Cell Value, String Constant - hDOLCC len=0 
' 0018     23 LABEL : Cell Value, String Constant - HZPMDcmh len=0 
' 0018     22 LABEL : Cell Value, String Constant - JVQAbdF len=0 
' 0018     23 LABEL : Cell Value, String Constant - LVzjyWxC len=0 
' 0018     23 LABEL : Cell Value, String Constant - oBeQqiOI len=0 
' 0018     26 LABEL : Cell Value, String Constant - pQeXvLMDmlc len=0 
' 0018     24 LABEL : Cell Value, String Constant - QaMttXmxg len=0 
' 0018     25 LABEL : Cell Value, String Constant - qTVSELYPDV len=0 
' 0018     22 LABEL : Cell Value, String Constant - rPHVFTR len=0 
' 0018     26 LABEL : Cell Value, String Constant - rPLwZGrIlea len=0 
' 0018     25 LABEL : Cell Value, String Constant - SCQthSkSgh len=0 
' 0018     20 LABEL : Cell Value, String Constant - UMwaN len=0 
' 0018     24 LABEL : Cell Value, String Constant - vJkkmAOCe len=0 
' 0018     25 LABEL : Cell Value, String Constant - WEnoZhzLWg len=0 
' 0018     22 LABEL : Cell Value, String Constant - xLqrCfa len=0 
' 0018     27 LABEL : Cell Value, String Constant - YrepxNKHeEhm len=0 
' 0018     22 LABEL : Cell Value, String Constant - zMZVVKF 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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