Malicious Office (OLE) — malware analysis report

Static analysis result for SHA-256 57f16f9e4f7d9de3…

MALICIOUS

Office (OLE)

36.0 KB Created: 2020-11-27 11:43:57 Authoring application: Microsoft Excel First seen: 2021-10-23
MD5: 203b4328e2bc13e44e40522df07cf05d SHA-1: 2a70ff13f21f5c5b2baa66d8e8539f41e5249f7d SHA-256: 57f16f9e4f7d9de35f81d778b5e488d57451210931e5fc1c15520f5a07830afd
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 that contains 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) 6653 bytes
SHA-256: 3c131a2bf20631937974d0be272d26940349d486fe99d2714126c70fb24cb0e2
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 -  NUJpuA
' 0018     23 LABEL : Cell Value, String Constant - built-in-name 1 Auto_Open len=7 ptgRef3d  Sheet!D164 
' 0018     25 LABEL : Cell Value, String Constant - cjDhNgLgFr len=0 
' 0018     24 LABEL : Cell Value, String Constant - eLScqSUnQ len=0 
' 0018     21 LABEL : Cell Value, String Constant - EyXkFX len=0 
' 0018     23 LABEL : Cell Value, String Constant - fBjsMmIk len=0 
' 0018     21 LABEL : Cell Value, String Constant - fqClJX len=0 
' 0018     20 LABEL : Cell Value, String Constant - GMBZt len=0 
' 0018     25 LABEL : Cell Value, String Constant - HWdLtUBiNE len=0 
' 0018     23 LABEL : Cell Value, String Constant - IxAMPJPh len=0 
' 0018     23 LABEL : Cell Value, String Constant - kczfUvgw len=0 
' 0018     23 LABEL : Cell Value, String Constant - kjJTasoA len=0 
' 0018     23 LABEL : Cell Value, String Constant - lBiVsprY len=0 
' 0018     25 LABEL : Cell Value, String Constant - LsTCkRRzwe len=0 
' 0018     23 LABEL : Cell Value, String Constant - MtuZRAcf len=0 
' 0018     27 LABEL : Cell Value, String Constant - NoPeRFWachpQ len=0 
' 0018     22 LABEL : Cell Value, String Constant - qspRahU len=0 
' 0018     24 LABEL : Cell Value, String Constant - tygOHjmcQ len=0 
' 0018     21 LABEL : Cell Value, String Constant - WpBatf len=0 
' 0018     20 LABEL : Cell Value, String Constant - xTght len=0 
' 0018     22 LABEL : Cell Value, String Constant - YCpLQnO len=0 
' 0018     25 LABEL : Cell Value, String Constant - ZojzRHnjEo 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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