Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 bc3fdffa1e7e391c…

MALICIOUS

Office (OLE)

35.5 KB Created: 2020-11-25 10:46:03 Authoring application: Microsoft Excel First seen: 2020-12-25
MD5: 5aee3eae5c2428445b26826eef0480e1 SHA-1: e27cf48d20523274d800619d41b390bdcea50f9c SHA-256: bc3fdffa1e7e391cb22dcaeb4910cb86a9bb349bfb5abdeddf4ac9193cd68fd3
140 Risk Score

Malware Insights

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

The file is an Excel macro-enabled document containing Excel 4.0 (XLM) macros. The critical heuristics indicate the presence of an Auto_Open defined name, which is a common technique for automatic execution upon opening the workbook. This suggests the macro is designed to run arbitrary commands, 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) 6398 bytes
SHA-256: a8dba4579a79a3e1bef4222e3d8ca16d153bf7a1eb74b671eeec347dac3b0ddf
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     15 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  ODnHBo
' 0018     21 LABEL : Cell Value, String Constant - AcaSkG len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!B139 
' 0018     21 LABEL : Cell Value, String Constant - cimakK len=0 
' 0018     24 LABEL : Cell Value, String Constant - cwZqbpEbf len=0 
' 0018     21 LABEL : Cell Value, String Constant - DzyqkQ len=0 
' 0018     21 LABEL : Cell Value, String Constant - eTpFyO len=0 
' 0018     20 LABEL : Cell Value, String Constant - HdrvH len=0 
' 0018     26 LABEL : Cell Value, String Constant - inuLhCplFvA len=0 
' 0018     22 LABEL : Cell Value, String Constant - kJAdujy len=0 
' 0018     24 LABEL : Cell Value, String Constant - kpmmGFPoO len=0 
' 0018     23 LABEL : Cell Value, String Constant - LhEXGRgV len=0 
' 0018     27 LABEL : Cell Value, String Constant - odKolXUDGknL len=0 
' 0018     21 LABEL : Cell Value, String Constant - OVcovu len=0 
' 0018     24 LABEL : Cell Value, String Constant - oYcmZbJGJ len=0 
' 0018     23 LABEL : Cell Value, String Constant - pOOnDvjw len=0 
' 0018     23 LABEL : Cell Value, String Constant - QsDUNvSt len=0 
' 0018     20 LABEL : Cell Value, String Constant - qttNZ len=0 
' 0018     23 LABEL : Cell Value, String Constant - uTsiFbQz len=0 
' 0018     20 LABEL : Cell Value, String Constant - VknvN len=0 
' 0018     21 LABEL : Cell Value, String Constant - wPvBhO len=0 
' 0018     23 LABEL : Cell Value, String Constant - znYPLgHc 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 LABELSST : Cell Va
... (truncated)

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