Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 b8c93d82aae5b2d4…

MALICIOUS

Office (OLE)

36.5 KB Created: 2020-11-27 11:47:45 Authoring application: Microsoft Excel First seen: 2021-06-13
MD5: 9386430f5a03bfba9b9d4a7d7b594bfe SHA-1: 0e9dac7f32f5c2fd8e12eb51fc142684c6e234ff SHA-256: b8c93d82aae5b2d4afac800f5a10192c13586022bc840919870c660f5331a1af
140 Risk Score

Malware Insights

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

The critical heuristics indicate the presence of Excel 4.0 macros with an Auto_Open defined name, which is a known method for executing malicious code upon opening the workbook. The macro sheet contains a reference to a dangerous formula API, suggesting it's designed to perform actions beyond standard spreadsheet operations. The extensive obfuscated data in the DOC BODY further supports the malicious intent, likely serving to hide the actual payload or execution logic.

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) 6544 bytes
SHA-256: 151089610d4e2bc54b9d79d2611a0206e5cd341d3c033bc6dd7c2dcf9cc4d7c9
Preview script
First 1,000 lines of the extracted script
' 0085     14 BOUNDSHEET : Sheet Information - worksheet or dialog sheet, visible -  Sheet
' 0085     12 BOUNDSHEET : Sheet Information - Excel 4.0 macro sheet, visible -  qkT
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!E192 
' 0018     24 LABEL : Cell Value, String Constant - bMHpQfZJi len=0 
' 0018     26 LABEL : Cell Value, String Constant - BQjcGXZkuSF len=0 
' 0018     22 LABEL : Cell Value, String Constant - ckveHVF len=0 
' 0018     23 LABEL : Cell Value, String Constant - CYgqZNXV len=0 
' 0018     20 LABEL : Cell Value, String Constant - EChGq len=0 
' 0018     25 LABEL : Cell Value, String Constant - EPtHixfhFH len=0 
' 0018     20 LABEL : Cell Value, String Constant - eRXHp len=0 
' 0018     25 LABEL : Cell Value, String Constant - FHBFkEcFQh len=0 
' 0018     22 LABEL : Cell Value, String Constant - gqVZCez len=0 
' 0018     23 LABEL : Cell Value, String Constant - hmVNAGDj len=0 
' 0018     27 LABEL : Cell Value, String Constant - jqrYXAYDCplV len=0 
' 0018     23 LABEL : Cell Value, String Constant - JyVvHCvH len=0 
' 0018     26 LABEL : Cell Value, String Constant - LJdCYlZhwQC len=0 
' 0018     20 LABEL : Cell Value, String Constant - mfLqU len=0 
' 0018     21 LABEL : Cell Value, String Constant - momZHH len=0 
' 0018     21 LABEL : Cell Value, String Constant - qoTBLG len=0 
' 0018     27 LABEL : Cell Value, String Constant - rLKAyKcCpaFq len=0 
' 0018     21 LABEL : Cell Value, String Constant - SkiMws len=0 
' 0018     26 LABEL : Cell Value, String Constant - TBGSyrClhKB len=0 
' 0018     21 LABEL : Cell Value, String Constant - vAZTfu 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 LABELS
... (truncated)

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