Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 8e93927a2e2df936…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:43:48 Authoring application: Microsoft Excel First seen: 2021-10-05
MD5: 05e43c15e913e0b92a4fb08bb47d0457 SHA-1: 7373b489ba18028d9d5d2e1c6f31bf9f12c3e31c SHA-256: 8e93927a2e2df9366b1100e8606704c3bd48f113b9ea85fbd58cdd6f76afad60
140 Risk Score

Malware Insights

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

The file is an Excel 4.0 macro sheet containing an Auto_Open defined name, indicating it will execute automatically upon opening. Heuristics indicate the use of dangerous formula APIs, specifically the RUN function, which is commonly used to execute arbitrary code. This suggests the macro is designed 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) 6806 bytes
SHA-256: 0eee37add6575724dcd3e03cdae0655c26d039c2f9aa451673387362342ca389
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 -  qHUCayQew
' 0018     27 LABEL : Cell Value, String Constant - adioZyfvLEvb len=0 
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!I172 
' 0018     25 LABEL : Cell Value, String Constant - baVjVAmwMv len=0 
' 0018     26 LABEL : Cell Value, String Constant - BOAECihDQHd len=0 
' 0018     25 LABEL : Cell Value, String Constant - CIobhFPfjH len=0 
' 0018     23 LABEL : Cell Value, String Constant - cMKyhUAN len=0 
' 0018     26 LABEL : Cell Value, String Constant - DDTKpjOMeDN len=0 
' 0018     22 LABEL : Cell Value, String Constant - EMVaMRF len=0 
' 0018     24 LABEL : Cell Value, String Constant - fQWdOmZRD len=0 
' 0018     26 LABEL : Cell Value, String Constant - GEPKJflOFHw len=0 
' 0018     20 LABEL : Cell Value, String Constant - KRBbD len=0 
' 0018     24 LABEL : Cell Value, String Constant - KZfGJtIKx len=0 
' 0018     27 LABEL : Cell Value, String Constant - NTEQhuPOcJKN len=0 
' 0018     23 LABEL : Cell Value, String Constant - PvSWsCwH len=0 
' 0018     21 LABEL : Cell Value, String Constant - PzQzVu len=0 
' 0018     24 LABEL : Cell Value, String Constant - SsGbsruFr len=0 
' 0018     21 LABEL : Cell Value, String Constant - UKjoit len=0 
' 0018     24 LABEL : Cell Value, String Constant - xppftVdQZ len=0 
' 0018     22 LABEL : Cell Value, String Constant - zKKsDNs len=0 
' 0018     21 LABEL : Cell Value, String Constant - zNoQpZ len=0 
' 0018     21 LABEL : Cell Value, String Constant - zOhDWh 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
' 00f
... (truncated)

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