Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 ac1733a40abd8c4f…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-25 10:43:50 Authoring application: Microsoft Excel First seen: 2021-06-28
MD5: e9732fa8de3effddfc0803afc0690212 SHA-1: 050d3b3a57c972df00c9bea122bba4c66701b9ee SHA-256: ac1733a40abd8c4f1e38312453c3da57015fea7b9ff14d9439c9d8dab1ec9728
140 Risk Score

Malware Insights

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

The file contains Excel 4.0 macros, specifically an Auto_Open defined name, which is a critical finding indicating potential automatic execution of malicious code upon opening. The presence of dangerous formula APIs like RUN further increases the risk. The macro sheet itself contains obfuscated data, suggesting an attempt to hide its true functionality.

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) 6610 bytes
SHA-256: f065896148658a086f6cdc07265e3ab3c99664bcdcd71a9a8746f7fffa6b72f4
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 -  zopKIoIBV
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!C188 
' 0018     27 LABEL : Cell Value, String Constant - fGzyGwGzyEZo len=0 
' 0018     21 LABEL : Cell Value, String Constant - gpVzFe len=0 
' 0018     20 LABEL : Cell Value, String Constant - HsQjJ len=0 
' 0018     26 LABEL : Cell Value, String Constant - LFeJmQBoKWA len=0 
' 0018     24 LABEL : Cell Value, String Constant - LZJzIXIfU len=0 
' 0018     20 LABEL : Cell Value, String Constant - Mmgji len=0 
' 0018     25 LABEL : Cell Value, String Constant - NoUflzFQNl len=0 
' 0018     24 LABEL : Cell Value, String Constant - osqyKvaFY len=0 
' 0018     22 LABEL : Cell Value, String Constant - oTjKoMw len=0 
' 0018     26 LABEL : Cell Value, String Constant - oYiAJArHaqf len=0 
' 0018     25 LABEL : Cell Value, String Constant - PDcbftQjHy len=0 
' 0018     24 LABEL : Cell Value, String Constant - PHFXPjXSY len=0 
' 0018     24 LABEL : Cell Value, String Constant - qOVuqXQed len=0 
' 0018     23 LABEL : Cell Value, String Constant - RNkjbqdw len=0 
' 0018     25 LABEL : Cell Value, String Constant - rxvqgegiWw len=0 
' 0018     25 LABEL : Cell Value, String Constant - VhPtxhUmSa len=0 
' 0018     24 LABEL : Cell Value, String Constant - XoSjjRFxh len=0 
' 0018     26 LABEL : Cell Value, String Constant - YnXuqLOEMxP len=0 
' 0018     21 LABEL : Cell Value, String Constant - yOTOfS len=0 
' 0018     27 LABEL : Cell Value, String Constant - ZYMAagdFgxxr 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/ SS
... (truncated)

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